This faint visual magnitude 13.0 galaxy in Pegasus was viewed by me at "my site" on the same occasion as NGC-255 (above): a very windy night on 23 November 2006, when conditions were so cold and blustery that I only looked at nine objects with my 10" Orion SkyQuest Dob. Light pollution was evident at the horizons; yet as before, I seem to have recorded in my viewing notes a detail not suggested by the mere atlas page open before me. Several other observations that night were surprisingly good ones; perhaps the transparency was exceptional. I could hardly tell what the seeing was like, with my scope being buffeted about by the gusts! Later I looked at a recording weather station, located a thousand feet below my observing point: wind was hitting more than 30mph, and I had to use heavy paperweights just to keep my atlas, and notebook, secure on the table next to me. Otherwise, something might have blown off, dropping over the sheer precipice past the road next to my scope, flying hundreds of feet straight down!

William Herschel's 18-1/2 inch aperture "speculum" mirror telescope (using the brightly polished reflective surface of a mirror consisting of a whitish alloy of tin, copper, and arsenic) captured this object for the great observer's eye. If his painstaking calculations are accurate, he was theoretically capable of observing stars to the 17th magnitude, until the moist English climate tarnished his "speculum", but his usual result achieved a limitation of 14th to 15th magnitude, which may be reached photographically or with CCD imaging, easily, by today's 10-inch aperture telescopes in a dark sky. Surprisingly for a hand-polished metal mirror, he reported very few instances of light scatter or flaring, even around bright stars (the rarity of this effect actually helped him discover a new type of object: the planetary reflection nebula, creating a halo of light reflected from dust particles and blown-off stellar atmosphere from a central star.)

Herschel spotted the object now called NGC-7042 in 1784. Its faint surface- brightness rating of 14.2 magnitude per square arcminute, and its moderately small angular diameter of 2.1 by 1.8 arcminutes, combined to make it a dim, obscure object, much fainter than the typical galaxies of Messier's catalogue. It is not likely to be viewed by amateur astronomers who cannot get to at least moderately dark semi-rural skies (which is just about the correct description of "my site".)

In his detailed search to correct and enhance the positions and ratings of objects in the NGC, Steve Gottlieb has viewed and reported about the galaxy, using a 17.5" Dobsonian. He comments that it is "fairly faint, moderately large, round, [with] bright core. Forms a pair with N7043 5.4' NE. A mag 12 star lies 2.3' NE between the galaxies" (this description is found on the NGC/IC Project page for the galaxy, and may also be accessed here, if you search for this exact string, less the quote marks: "NGC 7042".)

The POSS1 blue plate, used above for the picture, has been cropped to a field width of about 8 arcminutes in order to maximize the details of the galaxy. Just outside the picture, off to the upper left -- slightly more than 5 arcminutes to the NE of NGC-7042 -- is another galaxy, NGC-7043. It is much fainter (c.14th magnitude depending on the reference source, some of which claim as faint as 14.6, which would mean that 7042 is more than twice as bright), and only slightly more than half the diameter of 7042. It is interesting to learn that not Herschel but Albert Marth discovered it, 79 years later. Marth's telescope was the "Leviathan of Parsonstown", the 72 inch aperture reflecting telescope of Lord Rosse. No wonder he saw this object! It must have been quite distinct, if the Leviathan's mirror was not tarnished.

I was struck by the fact that William Herschel missed this galaxy. It would seem likely that he should  have seen it. I did not know of NGC-7043's dimness nor its close proximity on the night that I viewed 7042: for I was using only my Sky Atlas 2000.0 as a reference, which does not plot the fainter 7043! And, I did not have my laptop, which contains the star chart program that would have shown both of them, giving the appropriate data. So, either I too overlooked it; or it was simply too faint for the combination of my 10" scope, and the condition of the sky background glow, on the time of this observation. You can be sure I'll check this later, when possible, using my C-11.

My notebook records for NGC-7042 that it was a "gx, v faint, small patch with 6 mm Expanse [200x, 19' FOV, 1.3mm exit pupil]. Is there a halo? Is it offcenter E from the nucleus?" Apparently I did see the details of the faint outer arm in that direction. Since I had read absolutely nothing about it, aside from its magnitude and diameter, this observation was unbiased. This is one good reason not to go into an observing session with an exhaustive, detailed plan -- if you would like to see how well you can record unexpected details, or to pick up faint objects. Now, I'd be really pleased with myself if I had noticed 7043. Was it just below the visual threshold, or did I need at least the reassurance that something that faint was really there? Now, the spell is broken, and I can't accidentally 'discover' it myself...

Here's an obscurity! I could only locate two descriptions of amateur sightings (plus one small mistake) on public Internet websites, though there is always a chance it has been mentioned on a subscription forum somewhere. And, finding a picture is even more difficult. I could locate only one amateur image via Google; the cached thumbnail looked terrible, and the originating website would not come up. Why hasn't this object been investigated with more interest?

The discoverer was Dr. Max Wolf of Heidelberg Observatory, who photographed it in 1891, publishing a notification in the Astronomisches Nachrichten (AN 3027), which I have attempted to translate (freely) from the original German:

Of many other nebulae, whose reports are given here, the largest nebula was described in the previous year by Mr. Barnard around the stars G. C. 1420 Monocerotis, who was able to see that it extended over a much larger area than the circumferential disk of the star cluster. In that area, there is also a nebula not earlier photographed, at about the position of 6h 25m [right ascension] + 7d 30m [declination] and extending itself directly northwest of the 5th magnitude star 13 Monocerotis.

Presumably the coordinates are epoch 1875. "G. C. 1420" refers to NGC 2239, the open cluster at the heart of the Rosette Nebula; in 1883 Edward Barnard had traced the outer extent of the nebulosity, not seen before. I might add, parenthetically, that this is only one of many references that Max Wolf made to the observations of Barnard -- as well as respectful references by Barnard to Wolf -- which completely disproves the claim in Gerritt Verschuur's book Interstellar Matters that the astronomers were not only wary of each other, and very competitive, but NEVER referred to each other: this simply not true at all!

Wolf's measurement of the nebula was included in the Index Catalogue of 1895, in which it was described as "Neby, np *5 mag" (translated: nebulosity, north preceding star of 5th magnitude.") The star is SAO 114034 (4.47 magnitude, spectral type A0Ib: 06h 32m 54.23s RA, +07d 19m 58.7s dec.) The nebula measures about 15 by 10 arcminutes, and according to the listing of objects near the famous "Cone" nebula (NGC-2264) on the "Orion Arm page, is about 7 light years' diameter and 1,500 ly distant from earth. IC-448 is 3d 17m SSW from the Cone nebula, and 2d 20m north of the Rosette nebula.

The NGC/IC project page for IC-448 -- not directly linkable here -- identifies Lynds Bright Nebula 930 as being equivalent, but other resources specify LBN 931. The two Lynds nebulae overlap, 930 being much larger (30 by 20 arcminutes), to the east; 931 is to the west and encompasses the immediate region of 13-Mon: this is IC-448, which is shown in the heavily processed picture, above, from the POSS-UK survey blue plate, as being all the "fuzzy stuff" you can see around the star, in two 'clumps'. You may confirm these details with the Deep Sky Browser pages: for IC-448 (LBN 931) and for LBN 930.

My observation was done at "the site" on Saturday 1 October 2006, using my 10" aperture Orion SkyQuest Dob. I have prepared eyepiece performance charts for all my oculars and telescopes, using my own Eyepiece program (available free here), incorporating all the filter recommendations by Jack Marling for specific exit pupils. Therefore I have a good place to start my experimentation, as I can quickly find an appropriate field of view for my instrument, and know which filters will work in their most effective range for contrast enhancement. I examined all around 13-Mon, looking for the nebulosity, in both wide and narrow fields. Finally I settled on using my Orion "Highlight" 17 mm Plössl because in my previous tests I knew that it had higher light throughput transmission than any of my other oculars in that general focal length range: the best choice for extremely faint nebulae, and yielding slightly dimmer faint objects than my Orion "Expanse" 15 mm ocular. In my logbook I indicated that I thought that the Orion SkyGlow filter brought out the nebulosity, and drew what I thought was the brightest patch. My eyepiece chart indicated that the 17 mm Highlight would give me 70x, with a FOV of about 42 arcminutes and an exit pupil of 3.6 mm: right in range for the LPR, OIII, and UHC or hydrogen line filters. The SkyGlow is an LPR type, which one would use for reflection nebulae, as their bluish light is contained within the bandpass; the other types would diminish it.

My drawing was of course made from the scope's inverted, reversed view. I think that if one corrects for that, the spot that I was attempting to illustrate is the nebulous patch just to the upper right of the bright central star in the large (25 arcmin. square) photographic image above: in the orientation of that picture, the pole is up and the nebulous streak is pointing northward: almost straight up. Other aspects of the nebula may be seen better with a darker sky than I had on this particular occasion, and perhaps with a larger scope aperture (though then one must take care to get 13-Mon out of the immediate field, perhaps with an occulting bar.)

Among the very few references to the object by amateur astronomers, I found a mention by Albert Highe, who looked at it using a 12.5" Dobsonian at dark sky site near Hollister, California called Dinosaur Point, and stated only, "Because its [sic] near a bright star, its quite difficult to see." Jane Houston Jones referred to IC-448, using a Lake Sonoma, California observing site and her 17.5-inch f/4.5 reflector. There were many interesting and quite convincing descriptions in her report of numerous objects that she studied, but unfortunatly she seems to designate IC448 as an "open cluster": writing "NGC2259, NGC2252, CR111, IC448, CR97, CR96, CR92, CR104, CR107, CR110 Do22, IC2169 were other open clusters in this part of the Winter Milky Way I observed and checked off." I looked at all the objects in the immediate region and could not find an OCL with the designation "448" (nor anything remotely similar, or with numerical transpositions), so my guess is that she simply cut-and-pasted from a list of regional objects, wishing to include only clusters but accidentally nabbing also IC448 (goodness knows that MY articles probably have their share of mistakes too, and probably much more serious ones: that is why, for one reason, that I don't post my observations to other websites, as I want to be able to FIX the errors as soon as they are discovered!) Anybody else want to see if the nebula is visible?

0.5/2/4 degree finder chart: upright, correct.

Click here for my blog article reporting a sighting of IC-448 with my 4.7" refractor on 1/28/08.

There is little information about this planetary nebula on the Internet. I've turned up reports of sightings by six people, four of them Finnish amateurs. There are no amateur photos or CCD images to be found, every single picture on the net that I could locate being derived from the Digital Sky Survey sources. The NGC/IC project has not yet completed work on webpages for every object in the Index catalogue, so I had to do a little detective work to locate the discoverer: Thomas Henry Espinall Compton Espin, as may be confirmed by this scan of the appropriate page of the Second Index Catalogue. Espin and Dr. Max Wolf were the first 19th century astronomers to study the Cocoon nebula: see my article about it with informative links to a page about Espin, here.

There has been some significant interest in this planetary by professional astronomers. In 1996, Walter A. Feibelman of the Laboratory for Astronomy and Solar Physics, NASA/Goddard Space Flight Center, published a paper citing the work of Edwin Hubble, who photographed the spectrum in 1920, isolating nine emission lines; based on an exposure of 400 minutes with the IUE camera, several other spectral images, and his remeasurement of historical records, Fiebelman found "about 60 UV emission lines that were not detected before". Summarizing some important points in his paper: many other emission lines of carbon, oxygen, and iron were recorded or at least suspected. Strong stellar O VI emission lines were found which, along with at least a dozen other planetaries, characterize the object as belonging to the “O VI sequence”. Aller & Czyzak (1970) referred to IC 2003 as a uniform disk "..with a bright 'blob,' placed off to one side...They identified about 70 emission lines in the optical spectrum and also mentioned optical observations by Aller & Walker (1970) that show stratification effects."

I mention these last significant details, because my visual observation, a reprocessing by me of one of the DSS images, and another amateur's visual observation also depicted the brightness variation, as mentioned by Fiebelmann (which I did not know about until researching the object, the day after my own study of it in my telescope's eyepiece.)

As I've said so often, I don't go into most observing sessions with a fixed plan. Sometimes, when I use my Dob, I employ only a Sky Atlas 2000.0 chart and no other reference source (save the Companion to the Sky Atlas, a paperback volume that lists the plotted objects by chart, with extremely limited information about them: often only the type, position, and visual magnitude.) So, I had no preconceptions about IC-2003 when I looked at it at "my site".

The afternoon of Monday 8 January 2007 was unexpected sunny, brilliantly clear, and balmy in the San Francisco bay area. I finished my "chores" and readied myself at the very last moment for three or four hours of observing before the rise of the Moon at 10:27 pm. Normally, I prefer not to observe in the early evening, as light pollution at my locale in the mountains south of San Jose is rather severe, at least until after 1 or 2 am. But weather had been horrible during this winter season, and any possible moment for deep sky observing was to be snatched! I managed to be able to set up at 7pm, having donned my heaviest cold weather garments: layers and layers of pants, shirts, sweaters, and jackets (not to mention several head coverings.) But no sooner had I started looking when I realized I'd have to begin removing those layers, because the temperature did not drop precipitously after twilight commenced; instead it ROSE. By 8pm, the thermometer registered an amazing 59°F (15°C)! There wasn't a breath of wind. Soon I realized that my conditions were just like a summer night on the mountaintop; as if to confirm this, the seeing in the early part of the evening was probably the steadiest I'd experienced in many winters, perhaps reaching about 9 out of 10! Stars as faint as 8th magnitude were perfect pearly points in my eyepiece, surrounded by lovely, faint, unbroken, steady first diffraction rings. Double stars were exquisitely separated. But I wanted to spend the next couple of hours trying for faint deep stuff, benefiting from the amazing transparency and stillness of the air before the Moon ruined one's chances.

IC-2003 was the third object I sought. It was situated perfectly, high overhead where the stars were steadiest (I could spot ones as faint as perhaps 5.5 to 5.8 magnitude by eye: much better than usual at this short elapsed time past twilight.)

I have scanned and printed below my observing logbook note to show not only why I have talked about my "chicken scratchings", but also to indicate that I was at least trying to record more information than usual, for the purpose of adding something original to these reports (since some of my previous observation records have been so cryptic.) I described how the object looked with my highest powered eyepiece, and even added a 2x Barlow to that magnification. Since I had only recently installed a new Crayford focuser in my Orion 10" SkyQuest Dob, I was still revelling in the superb new experience of, at last, being able to focus this telescope REALLY sharply (something the old focuser wouldn't do.) I frankly had not realized before how good the optics in this cheap telescope really are; it gives my C-11 a run for the money. With the smooth action of the focuser, lacking any astigmatism or jerkiness, I was at last able to use comfortably my 3.7mm Orion "Epic" ocular [323x, 10' FOV, 0.8mm exit pupil], and for the purpose of studying the incredibly small planetary disk, I added my 2x "Shorty" Barlow [646x. 5' FOV, 0.4mm exit pupil], for the highest satisfactory magnification I have ever used for an astronomical observation with this telescope.

The planetary nebula's disk measures 7x6 arcseconds; it is rated at 11.6 visual magnitude (7.35 magnitude per square arcminute surface brightness), with a 15.4 magnitude central star. How did it look to me?

As you can see from my "scratchings", I perceived that it was a "small disk of slightly uneven brightness, possibly brighter to the SE? Thought I saw glimpses of brightness in the center: illusion?" The longer I watched it -- and this was extremely difficult, as the high magnification speeded up the movement of the object through the field of view, necessitating quite a bit of struggling with the clumsy alt-az mount -- the more I became convinced that I was seeing something in the center, a brightening that was extremely sharp and point-like; but it was not steady. It "flashed" in and out. I suppose it is theoretically possible to see a 15.4 magnitude star in this scope, since I can really quite easily do this with my C-11 (but that scope has a motor drive, and larger aperture, making such an observation infinitely easier.) I am not really willing to claim that I saw the central star, because it just wasn't steady and repeatable. But, I noticed that there was uneven surface brightness, and tried to indicate this in a (very crude) sketch. Since I was anxious not to lose dark adaptation, the sketch is poorer than it could have been; and it is out of scale compared to the full field sketch without the Barlow. (And I was in something of a hurry, wanting to get to as many objects in the region before the Moon rose.)

Update: As is my wont, I observed this object a day later, at 9:50pm on 9 January: same place, same scope. The seeing was steady but the sky was slightly 'softer' than before. With 646x, the "flashing" of brightness was apparent again, but perhaps not quite as distinct. It is difficult to hold an object in the field at this power; but over a period of time I decided I could detect two discrete flashes in different parts of the nebular disk, not just one. The brighter flash was near the periphery, and probably agrees with the enhanced photo, below. The other flash was seen less often, and could possibly be near the center.

There are four reports of seeing this nebula on the website of the Finnish Deep Sky Archive. Observer Jere Kahanpää, in Jyväskylä, Finland, looked at it with a 205mm aperture Newtonian in 1992, finding it to be at 63x "Stellar, surrounded by a group of stars of same magnitude"; later at an unspecified date, he used a Meade LPR filter and determined that it was "Very small. Maybe somewhat concentrated, round, quite sharp edges. Within a nice small asterism." My friend Jaako Saloranta, in Rajakylä, Vantaa, Finland, used his 8" aperture Dob with 122x and O-III filter, stating that it was a "Very small, stellar planetary with even brightness smooth disk." Juha Ojanperä (Friitala, Ulvila, Finland) used a 255 mm Newtonian at 145x: "Stellar planetary nebula, no details were seen." A larger aperture scope seems to have yielded much more information: Iiro Sairanen (at Härskiänsaari, Ruokolahti, Finland) employed an 18" Newtonian, and like me was able to use really high power. At 618x: "Quite small but very bright planetary nebula in Perseus. Stellar at low powers but at 618x there are some details on view. A clearly brighter crescent-shaped area in SE quadrant, annular? A 13th mag star on the West-side. The planetary is stellar or overexposed disk in every photo I've seen so it would be nice to see other observations of this." These observers all provide very helpful drawings; but your browser has to have Java enabled to bring up the pages. Iiro's picture is quite informative, and captures with careful shading his impression of the brightness variation, while mine is too crude to really represent what I saw by eye.

In an Internet post dating back to 1999, the experienced PN observer Yann Pothier comments that in his 17.5" Coulter Dob, the nebula was "visible at 45x; just non-stellar at 125x; OIII filter provides a very good contrast gain; at 145x and OIII, homognenous and sharp, about 9" in diameter, shapeless; a mag13.5 is 12" to the SW." And, Armin Herrman, observing in Thailand in 2004, reports that in a 15 inch Obsession f/4.5 Dob, IC-2003 was "brighter than its neighbor IC 351 which has a catalogued brightness of 12,0magv and should therefore be half a magnitude brighter than IC 2003! At 342x the PN shows a 7" disk that is brighter in the center. No central star seen. I did not see any color either."

I downloaded all the various DSS images using the Palomar, UK, and Hubble GSC pictures, and found that it was indeed true that most showed an overexposed disk. Only one picture had any real trace of brightness variations: the GSC 1 image. I examined this in a close-in region of 1 arcminute, capturing just the planetary and the star that is 18 arcseconds to the SE, which is GSC 2365:201, 13.4 magnitude. I blew it up and looked at the pixels: yes, the brightness variation was clearly shown, though each pixel was so large that not much detail could be resolved. I did a bit of contrast stretching and smoothing; the result is not guaranteed to be scientifically valid, but it does tend to suggest the bright "blob" mentioned by Fiebelmann, and at least something of the arc shown by Iiro. My own view, if my drawing is representative, was not quite as distinct.

If you would like to try examining this nebula, Mikkel Steine's Deep Sky Browser page for IC-2003 will supply finder charts and more information.

I have the distinct conviction that I did see some trace of this large, incredibly faint object. But the story is a bit complicated...

Abell 7 has a gigantic angular diameter of 14 by 11 arcminutes. The rated surface brightness of this relatively close, old planetary nebula is 18.3 magnitude per square arcminute (with a photographic magnitude 13.2 rating.) Can it be true that I could see any trace of the object at "my site", and with merely a 10" aperture scope? I'll leave it to my patient readers to decide, from the evidence given below.

To illustrate the faintness of this object, compare the modified, "contrast- stretched" image that I produced, above, with the original download (reduced in size slightly but otherwise unprocessed) of a 30 arcminute square section of the POSS/UK blue plate to the right. There is almost no immediately visible trace of the nebula, but the latent data are present if one takes the trouble to iterate many steps of contrast enhancement (which turns the picture's bright parts to rather ugly, burned in patches: note particularly the 14.5 magnitude galaxy, MCG -03-13-058 / PGC 16611, which has become a solid narrow ellipse just slightly above and to the right, or the west, of the planetary's center.)

Abell 7 is plotted in the Sky Atlas 2000.0 with its PK designation. I judged from the clarity of the sky (despite some residual light pollution to the east, far away from the region of the nebula) to be reasonably good at "my site" on the night of 9 January: the seeing was steady, with about 1 arcsecond resolution. The weather for the past two and a half days had been exquisitely clear. So I tried for the nebula, at its transit, assuming from past experience that I could almost always find the objects plotted in this atlas (with the exception of some of the faintest and largest nebulous patches, which require a darker site and a special wide-field telescope.)

At first, when I centered my field of view on the very distinctive apparent pair of stars close to the nebula -- SAO 150106 (7.5 mag) and GSC 5600:757 (10.3 mag), about 2 minutes separated -- that I could see what I noted as "a vaguely nebulous patch [to the east], around a zig-zag group of faint stars ranging from 11 to 12th magnitude." I used my 15mm Expanse ocular [80x, 49' FOV, 3.2 mm exit pupil] with no filtering and saw this indistinct glow; it was slightly more apparent with my 21 mm Stratus [57x, 70' FOV, 4.4 mm exit pupil] and became even more distinct with my SkyGlow filter, with averted vision. But, what's this? There was also a large, "uneven patch of nebulosity" on the western side of those two stars: this, in fact, turned out to be at least part of Abell 7. I tried higher and lower magnification: with my 32 mm eyepiece (an Orion Sirius model which, frankly, I don't like very much because of its poor eye relief) the sky was generally too bright; with a 9 mm wide field Expanse, the nebulosity disappeared though the background was slighly uneven as I scanned around the field. Adding either an UltraBlock or an OIII filter made this nebulous region stand out better.

The atlas plotted only a single star with the planetary immediately adjacent. But, try as I might, I kept preferring to think that there was more glow on the OTHER side of those two stars, than where the Abell object was indicated.

Ignorance is, as they say, bliss. But, in this case, it was torment! Were the nebulosities illusions? If not, which patch was the planetary, and what, then, was the "other stuff"?

As soon as I got home from observing, in the wee hours of the morning, I fired up the Internet and started researching the matter. It became immediately apparent that Abell 7 was indeed about 10-1/2 arcminutes to the northwest of those two stars, and not the other nebulous patch I had seen as well, toward the east, which appeared even perhaps a bit brighter by eye (no filter employed.) In other words, I did see some nebulosity: two patches, symmetrically positioned both to the NE and NW of those two stars: the western side being Abell 7, which responded to the OIII filter, and the eastern side being some other faint glow, which responded somewhat to my SkyGlow filter.

On the English-language version of Uwe Glahn's website article on the Abell planetaries, he comments that with his 16" telescope at 51x with OIII filter, Abell 7 is visible "only with max. AP [? -- srw] and [OIII], large, round PN, faint but can hold PN with averted vision, some faint structure, fainter to its middle, dark wedge from the west, PGC 16611 easy to detect, 10' NW of the PN, elongated 1:2", quite a definite observation. I did not detect PGC 16611, but probably merely because it had not been plotted on the Sky Atlas 2000.0 and thus wasn't sought out carefully by me; it is the sort of galaxy that would show up in my larger C-11 telescope. The very experienced Steve Gottlieb contributed one of his typically excellent writeups, observing at the California dark sky site Lake Sonoma with his 18" Starmaster Dob:

...at 73x and OIII filter, this ancient planetary appears as an extremely large, ghostly glow, perhaps 6' in diameter. Although the surface brightness is very low, it was visible as an irregularly-shaped, hazy patch involved with 5 or 6 stars on the south side. The edge of the planetary is better defined on the southern periphery and appears to fade out on the N side, so I was probably viewing only a portion of the object. Once identified, though, it was not difficult with averted vision.

Coincidentally, there's a very faint galaxy, MCG -03-13-058, just outside the edge of the halo, 10' NW of center! This required some hunting, though, as it's also a difficult object. And of course, the OIII filter had to go.

When I first wrote up this article, after only one viewing of the region, I located and linked to a 2001 report by Stathis Kafalis, who was seeking Abell 7 using a site that was infinitely better than mine (Canadas Tenerife, 28° latitude, 2300 meters elevation): with a 10" f/4.5 Dob,

At 43x (32 mm WF) without filter approx. 15' west of this position [i. e.,"RA 05:03 dec -15:36", referenced earlier in his post, the "official" position center for Abell 7] a group of 5-7 Stars of 11-13 mag. With OII filter sometimes extremly faint diffuse glow around and near this group of ~8' diameter. Is it the nebula or just the stars scattering through the filter? Very unsecure.

Unfortunately I misconstrued Stathis' description at first, which Sue French pointed out; she also helped me straighten out a blunder I made in one part of the original article where I had transposed E/W directions. With that correction, Stathis does not seem to be describing my anomalous nebular spot. If one changes his "west" to "east", then he could be describing my nebulous patch. It is probably more likely that he was seeing a relatively bright outlying edge of Abell 7. There are some stars within the periphery of the nebula, and a few c.12th magnitude stars to the west; a Hickson cluster to the northwest; but as I saw it, a very distinct grouping of stars to the EAST: they are indeed in the range of 11-13 magnitude and very well resemble his description for stars he describes as being to the "west".

In order to determine if 'my' perplexing glow was really there, I plotted the central coordinates based on my drawing, using a star chart program, determining approximately where it was centered; then I downloaded an equivalent region from those coordinates from the POSS/UK2 red, blue, and infrared plates. After doing even more heavy processing, I was able to bring up the faint background glow ONLY on the blue plate (tending to indicate that it could be reflection nebulosity, or at least a shorter wavelength than the red and IR plates would register.) In these three versions, heavily reprocessed, you will see in each picture those two stars identified above (smeared together into one overexposed mess), plus the edge of Abell 7's disk in the lower right hand corner. I believe from the blue plate it can be determined that there is a nebulosity around GSC 5901:972 (10.2 magnitude, at RA:05h 04m 12.7s / Dec:-15d 30' 18" Epoch 2000) and running for several arcminutes to the east of it ; there is also a somewhat fainter patch around and extending to the east of the two stars close to Abell 7, described above.

So, there is nebulosity there, recorded by this one picture, and it was likely right at the threshold of my perception -- even without a filter! The image in this paragraph, to the right, is yet another attempt, using an alternative method with different software, to process the faint background glow in the POSS/UK2 blute plate with less overexposure on the highlights. As distinct as this glow may be, however, an amateur CCD imager with today's best equipment could certainly do better, showing more nebulosity with better detail and less noise, using an appropriate LRGB exposure: any takers?

My conclusion is, therefore, that Abell 7 was at least partially (and barely) detected by me -- perhaps one small area of a brighter- than- average spot, "bright" being an entirely relative term! -- though it took some careful study from my drawing to determine, from relative positions, that it was at first confused with the apparently brighter variation in background glow: surely very similar to one of William Herschel's famous "regions of milky nebulosity."

As is my wont, to confirm a very difficult observation and see if I had been mistaken or deluded, I went to "my site" again on the night of Thursday, 11 January 2007 (sadly, too late to be able to see the setting of Comet McNaught.) But by the time that Abell 7 was transiting, conditions were probably as good as they had been 48 hours earlier: Sirius barely twinkled; a sharp line of temperature demarcation down near the valley floor had caused an inversion that was keeping much of the skyglow from Morgan Hill from escaping upward; and some clouds had drifted north of my mountain top, cutting off much of the light from San Jose. Once again, I looked closely at the region of Abell 7, and drew a sketch that was similar to the ones I had made previously, with the glow of a bright part of Abell 7, as well as 'my' anomalous nebulous patch to the east of it. (Unfortunately, it is immediately apparent, when comparing it to a star chart plot, that some of the fainter star positions are grossly inaccurate, the result of my having to walk about 20 feet over from the scope to the table with my charts and notepad, and back, several times while making the drawing!)

On this second night of observation of Abell 7, I found that using either my OIII or UltraBlock filter plus the 25 mm Orion Ultrascopic eyepiece yielded best contrast [48x, 1.1d FOV, 5.3 mm exit pupil]; I also tried for the widest possible field, using a 2" barrel 42 mm eyepiece, a bit too low in power for a practical exit pupil that fit my eye, but nevertheless still showing the two nebulous patches quite distinctly, employing a 2" UltraBlock filter [28x, 2.4d FOV, 8.9 mm exit pupil]. Unfortunately I did not have a 2" ocular that would yield a smaller, practical exit pupil of 7mm or less; I had acquired the 42 mm Erfle-type eyepiece for my C-11, not for the "fast" Dob.

Sue French provided some cautionary skepticism in her analysis of the situation as I had reported it. She wanted me to make certain that "my" glow could show up in more than just one picture: so I downloaded a one-degree region, centered on Abell 7's coordinates, from all the available images in the Digital Sky Survey. I then cropped, processed, stretched, and converted each to a negative view to make the background as distinct as possible.

The results indicate that the POSS1 blue plate -- at left -- has only a very vague and poor image of Abell 7, with a quite uneven background illumination, scratches, and no trace of "my" alleged nebulosity. It's a wonder that George Abell was able to detect the planetary with the techniques available years ago.

But the two GSC pictures did have at least something registered above the noise level, as well as much better distinction of Abell 7: GSG2 had more contrast, and carried more information.

GSG2 (below, left) does seem to suggest the slightest trace of nebulosity. However, the POSS2/UK blue plate (below, right) does indeed have the best rendering of my alleged nebulosity, though not as much density in the image of Abell 7 (admittedly, all of these nuances are quite easily altered by further tinkering; my reprocessing is not alleged to be scientifically precise and repeatably valid.)

These images of Abell 7 nevertheless are quite convincing that the "mean surface brightness of 18.3 magnitude per square arcminute" is not representative of every spot of the nebula. The reason I could see it with a 10" scope is surely because some places are significantly brighter and denser than others.

I have created a finder chart for Abell 7 on which I have used a spray-tool to indicate my claim of an "apparent glow" in the region, if another observer would care to look for it. Be aware of course that the giant purple circle pattern representing Abell 7 in this chart is merely an indication of position that has been colorized by the star chart program for clarity, and is not a realistic depiction. Owners of larger scopes than my 10" should also look for the Hickson galaxy cluster number 32, as well as nearby MCG -03-13-058.

Finally: thanks are extended to Sue French for her various suggestions and caveats, assisting me in the analysis of the observation and images.

0.5/2 degree finder: upright, correct

UPDATE: I now have some confirming observations of Abell 7, and even the glow to the east that is described above. While struggling to see details of some other faint objects in Lepus on Monday 19 February 2007, I found Abell 7 using a newly acquired Orion Q-70 2" barrel 32 mm ocular, and UltraBlock filter. And four days earlier, on Friday evening, I saw both the planetary and the nearby easterly nebulosity with that ocular in my 10" scope, recording in my notebook seeomg a "glow nr triangle of faint * even w lots of bg light." Thus I have quite good confidence that my initial impressions are repeatable, and should be possible by other observers.

UPDATE: Likely Independent CONFIRMATION!  My European observing colleague Jaakko Saloranta was initially somewhat skeptical of my claims of having seen the vague, uncatalogued glowing patch described above. But he told me that he planned to look at the nebula Abell 7 with his 4.7 inch refractor during his trip, in April 2008, to La Palma (part of the Canary Islands near Spain, with observing sites that range from 2,500 to over 7,000 feet above sea level, and site of several professional observatories.) I wrote to him recently and queried if he "ever had a chance to check out the possible existence of a visible glow to the E of the main portion of Abell 7 that I felt I'd seen a couple of times?" And he replied immediately, with caution:

I did indeed but I am very skeptical about actually scanning the sketch and putting it to the net. I think I saw the very same glow surrounding the group of stars as you did! I have the sketch here, ready to go and all but still... well I think I'll just leave it here with the Vela SNR, NGC 3242 (naked eye) and Sh2-240 - unscanned!... The main problem, however, is the scanner. I tried to scan my Simeis 147 today but all I got was [a] few wisps here and there not even showing half of the sketch! This has always been a problem... and continues to be until the day I buy a new scanner.

Perhaps both Jaakko and I have been "burned" when some carefully done observations have been negated by arguably prejudiced amateurs, who NEVER looked at the same objects in a similar test under equivalent conditions, but rather concluded merely from "theory" or inference that the observations were unlikely. This is the perennial problem of "eye astronomers" who, since the days of Galileo, have had difficulties in persuading their colleagues of their personal experiences. My old mentor, the late Dr. Donald E. Osterbrock, referred to this as "The Not-In-My-Telescope Syndrome", and like all professionals, he was grateful for modern photography and data-gathering techniques. But, eye-astronomy still has some use, and honestly and carefully reported observations by skilled persons should be checked in an eyepiece, before being prematurely dismissed. -- srw, 9/26/08

'Visible only with 14 - 20 inch scope' -- the claim made by some high latitude observers who work in skies at low altitudes. But, it's just not so! Though the object was difficult, and required more than an hour's time to find, study, and then go back and confirm, I've acquired the planetary with my 10" Dob at "my site". It was frustrating; wasn't very 'satisfying'; and was a time-consuming, fatiguing experience: but, it was definitely achieved.

Between cold fronts, the northern California/SF bay area weather in January 2007 was surprisingly good for deep sky observing. During several nights and two early mornings, approaching the new moon, I found myself amazed at the steadiness of the atmosphere at 3,400 feet altitude above sea level, near the Pacific ocean. Whatever success I have in finding such obscure and faint objects as this one is due almost entirely to my altitude, and to the stable laminar air masses with which the mountain ranges around the famed "silicon valley" are blessed: thus, at Mt. Hamilton's Lick Observatory in the late nineteenth century, Barnard and S. W. Burnham were able to make many pioneering observations that, at the time, perturbed other professional astronomers, whose institutions were located unfavorably. My site is about 800 feet lower than the peak of Mt. Hamilton, but is closer to the Pacific ocean and separated from San Jose direct lights by the edge of the mountaintop. On favorable nights, lower elevation fog and clouds render it a true "dark sky site"; but unfortunately that happens rarely in the dead of winter. On the late night of Wednesday, 17 January, the light dome from San Jose was strongly glowing, turning the northern sky into a bland gray-blue glow, wiping out naked eye stars fainter than about 4.5 to 5 magnitude. BUT...to the southwest, the sky was incredibly darker, and at the zenith -- due to the wonderful transparency of the air -- it was excellent, reaching 6th magnitude.

I had been attracted to the idea of searching for Minkowski 1-18 from reading about it on the Yahoo Planetary Nebula group, and from one or two web pages that deigned to mention this obscurity. It was discovered in 1946 by the famed astronomer and director of the original Palomar Sky Survey, Rudolf Minkowski (according to this page of the 2000 version of the Kohoutek catalogue.) Because the telescopes at Palomar were not yet in full operation, I was curious about how the Minkowski planetaries of 1946 were discovered, and found nothing explicit on the Net. I was just about to send an email to my friend Don Osterbrock of Lick Observatory, who had written a monograph on Minkowski, to ask him for the details: but I discovered to my great dismay that he had passed away from a heart attack (as reported by Dr. Bill Sheehan in a Sky & Telescope web article) only a week before the day that I am composing this entry in my Fuzzy pages. However, there is a hint that I found about the discoveries of other Minkowski planetaries, in the long and useful list of 450 planetaries compiled by Jay McNeil: "Mount Wilson Plates" is the attribution for many of them, and thus it might possibly be true also for Min 1-18, unless I find better information subsequently. Could these plates have been taken during the World War II blackouts, when the Los Angeles basin lights were not blazing normally? In Minkowski's three papers ("New Emission Nebulae") in the Publications of the Astronomical Society of the Pacific (1946-48, links available on this list of references) one learns that most of them were measured on plates taken with the 60 inch and 100 inch telescopes using either the Newtonian or Cassegrain focus, and others were found on plates taken by John Charles Duncan and Albert George Wilson using the 18" Schmidt telescope at Palomar (an instrument which began operation in 1936.) But the object catalogued as Minkowski 1-18 does not appear in the lists of new objects given in those papers, adjusting for the J1950 coordinates, so I am still a bit puzzled about the details of the initial determination.

Minkowski 1-18 is fortunately situated only about 23 arcminutes almost due north of the famous planetary nebula NGC-2438 (07d 41m 51.43s RA, -14 43 54.9 dec), which glows distinctly "inside" the northern periphery of the open star cluster M-46 -- though it is most likely a foreground object -- putting it in an interesting region of the sky, close to very well known objects. Fortunate... for low-latitude observers close to the equator, that is. For at higher latitudes, so much atmospheric extinction occurs that even the very bright 2438 becomes vague, washed out, and pale. Luckily my local observing latitude is at approximately 37d, with M46 rising well above the heavy dull air blanket near the horizon. At transit, M46 is high enough to take on sharp clarity, "its" planetary nebula standing out beautifully (in fact, in years past when I was much younger, it seemed to glow quite blue at low power; now, at my upper-middle age, it is merely a distinct light gray.)

My determination to seek out Min 1-18 stemmed from some skeptical remarks made by an observer in the British Isles, who found the nebula to be a supreme challenge, even with a 20" aperture scope. I could sense that he looked on other observer's descriptions as being questionable, especially when relating the alleged "claim" that it had been seen by someone with a 10" aperture instrument. Well, the British Isles -- even the dark sky sites inland -- are simply no match for the California Pacific coast mountain ranges. I tried to get Min 1-18 on a disastrous trip to a staggeringly dark sky site in late December 2006, but moisture ruined the occasion, wasting almost 600 miles of driving. I'd have to try again but at the relatively light polluted site I normally use near home. So, philosophically, I just girded my loins for the struggle.

Success in finding this nebula is really determined by proper preparation. Unlike many of my spontaneous observations, merely seeing an object listed in my atlas and 'going for it', this nebula is so faint and tenuous -- by most accounts -- that one should really be familiar with the star field. So I used my planetarium program to print out a chart that contained a near field with stars down to 15th magnitude so that I could get a good correlation of shapes and relationships between the chart, and the eyepiece view. But I made certain NOT to look at a photograph. I consulted only the numbers: the location; the visual magnitude (14.0); the size (33 by 28 arcseconds); the central star (19.1 magnitude: impossible to detect with a 10 inch scope by means of the human eye.) I did not want to prejudice myself completely, and to create any self-delusion and conviction that I 'saw something I hadn't seen'.

The early part of the evening was propitious, and I had intended to wait until about a quarter of twelve o'clock, when the nebula transited; but I noticed some fleeting clouds to the NE and began to worry. So, an hour before transit time I started working on the object. The blinding and spectacular star Sirius, the beacon for finding Puppis, was so steady that one had to stare intently with naked eye to see even the slightest twinkling: an amazing phenomenon for the normally turbulent winter. Soon I had a beautiful view of M46 and the large, obvious planetary that shines through it.

Moving my scope north and increasing the magnification, I quickly came onto the exact location and could match the brighter stars. At higher power, the distinct pattern of three faint pairs of stars, which 'surround' the nebula in a broad arc, became fixed in my mind so that within ten to twenty minutes, I could move the scope away and return it immediately to the recognized position.

My logbook indicates that at about 11 pm I wrote, "I got it!" And at 11:15 I made my first of two drawings, noting at first that "Filters n. g. at any power, even low. Had to use high power, no filter: best with 3.7 mm" [323x, 10.2 arcmin or 0.2 deg. FOV, 0.8 mm exit pupil], which was my Orion "Epic" ED ocular. I also found that it was visible with a 6.3 mm Orion Highlight Plössl [191x, 16 min FOV, 1.3 mm exit pupil], and even used that eyepiece with my 2x "Shorty" Barlow [382x, 8 min FOV, 0.65 mm exit pupil]: no wonder filters would not work, as none of them would be in the proper exit pupil range and would cause too much extinction of light. In fact, that I could use such high magnification reliably with my Orion SkyQuest Dob was only a recent phenomenon, thanks to the focuser upgrade I had performed a few weeks earlier, installing a new Orion Crayford-style focuser to replace the old wobbly yet stiff rack-and-pinion job: I frankly doubt that I could have seen the nebula with that focuser at all, because I could not have been able to adjust the scope properly at magnifications over 200x.

I did of course test my filters, recording that "perhaps I saw it, barely, once momentarily with 7.5 mm ocular + UltraBlock" [160x, 18 arcmin FOV, 1.6 mm exit pupil], using my Orion Lanthanum eyepiece that I appreciate for its exceptionally high transmission. I also noted that it could be "detected, erratically", with the 12.5 mm Lanthanum plus SkyGlow LPR filter [96x, 31 arcmin FOV, 2.6 mm exit pupil], but both were only done after I had studied the object's visibility for more than a half hour with NO filters, making sure it really was perceptible. One has to be careful about the magnification employed, as low power will confuse the eye. The faint stars right on the periphery of the nebula's shell are indeed quite visible, and in a wide field might tend to create the optical illusion of a faint glow. High magnification will make them distinct -- at least in my scope, most of the time -- and show that they are not situated right on top of the actual faint fuzz patch. I wrote after almost 45 minutes of painstaking experimentation and observing that "It comes in and out every 2 to 4 seconds but does not stay absolutely steadily visible. Vfaint, right at threshold of perception. Adjust eye position to find best averted direction; can't quite hold directly straight-on." Then, another ten minutes later, after even more testing, I wrote with more assurance, "ALMOST straight-on using 10 mm Plössl + SkyGlow LPR filter" [120x, 25 arcmin FOV, 2.1 mm exit pupil]: exactly in range for best efficiency of contrast enhancement for the filter, in my particular scope.

The fact that I began detecting the nebula without any filter at all, by finding the precisely best exit pupil and magnification, would eliminate any tendency to be fooled by "optical illusions caused by filters", a claim that I've read a few times among skeptics who discount the observations of OTHER people who seem to be much better at finding faint nebulae. And the fact that the OIII filter did not seem to work was no surprise to me: because it functions best at low powers, where the nebula was just too small to be detected by my eye. Surely though the OIII will function properly in a giant aperture scope.

One other detail was noted by me, though not with absolute certainty: "perhaps it's not really round." I had the distinct feeling, in the moments that it 'faded' up above the background noise level, that it might be either unevenly bright or rather oval or rectangular to the eye. This is somewhat suggested, in fact, by the POSS/UK blue plate, above, which shows at least that it is somewhat brighter on the northern edge.

The nebula was incredibly faint, perhaps the dimmest object I have yet seen with this 10" telescope at "my site" (the image at left is my attempt to simulate how it might look at best in an eyepiece view, created by me with a modification of the POSS1 blue plate image in a 5 arcminute field, with the contrast of the nebula and some of the faintest stars "toned down" considerably.) Though the visual magnitude of 14 is not especially low -- and it does show up well in the Palomar Schmidt and UK Digital Sky Survey blue plates -- and the surface brightness is a relatively effective 12.53 mag/per square arcminute of area, at my location at +37 d north latitude the object was surely subjected to some undesirable atmospheric extinction below optimal. Even lowering the latitude by the 4 degrees at Palomar Mountain in San Diego county (33.3d, where the Digital Sky Survey POSS Schmidt plate of Min 1-18 was taken, and registered well) causes the planetary to gain significant clarity. Better still is the locale of the UK Anglo-Australian telescope, used for the DSS survey blue plate picture that I cropped in a 10 arcminute field at the top of this discussion. One does wonder, though, how well it could ever be seen at the few deep sky locales used by amateur astronomers in England (higher than 51 d.): no wonder amateurs there find the object an almost insurmountable challenge. But they should NOT discount the gains made by observers at mountain tops closer to the equator!

Indeed, I found one good viewing report on the public Net, in a webpage article by Jenny Kay, FRAS: observing with a 12.5” f/5 Newtonian telescope in a "semi-rural home site" in Lobethal, South Australia, she describes the object as being at "240X: Extremely faint, relatively large, round, 30” in size. With the UHC filter, the planetary appears bright. 480X: Faint, smooth glow throughout, with a faint stars [sic] on the NW and SW edges." Jenny also comments that "The skies here typically have a limiting naked-eye magnitude of 6.1," which would mean that she has an advantage over me: not only is the planetary better situated for her location of about -35d north latitude -- using my planetarium program and changing from my location to hers, at the time of culmination of the object, I calculate that it would be 32 degrees higher in her sky than in mine! -- but also MY naked eye limit toward Puppis, on 17/18 Jan. 2007, was somewhere in the range of about 5.5, and thus not nearly as high contrast as hers. Yes: there in Australia, using merely a 12.5 inch scope, perhaps the object is almost an easy find: I can understand how she can call it "bright".

'Skyhound' Greg Crinklaw, the astronomy software developer, has an interesting webpage about Min 1-18. He lives in Cloudcroft, New Mexico, with an infinitely better sky than even mine in mountainous California. Yet, he found in his 18" scope that the object was utterly invisible without the OIII filter. As he can use his large scope at a lower magnification than mine and yet have an exit pupil in range of the filter (which I cannot at the power needed to be able to see M1-18) perhaps the image contrast enhancement provided by the filter does indeed 'work'; yet I'm surprised he says that there was absolutely "nothing" without the filter. Yet, he was using 166x to find it "readily apparent". At this magnification, perhaps the object was simply too small to register clearly without making the background darker. I achieved best contrast, however, by using not a filter but rather by employing higher magnification and getting a larger image scale... but my exit pupil was usually smaller than the ones used by Greg. Even at his power of 430x, which he says just sustained the object in view, his exit pupil would have been about 1.1 mm (assuming that his scope is f/4.5 and that he used, say, a 4.8 mm TeleVue Nagler.) I was finding that the nebula could be most easily detected without a filter at an exit pupil of about 0.8 mm, at 323x. I wonder if Greg spent as much time as I did, cumulatively, testing all possible combinations: I must have tried 3/4ths of my oculars, and all my filters, over a total period of time of nearly 2 hours!

For the adventuresome, I have included a wide area finder chart that I made up, showing the close proximity of this planetary to the famous one "inside" M46. I also recommend trying the Deep Sky Browser page for M1-18, and creating one's own customized finder chart.

0.5 degree finder: upright, correct

• Link to Jaakko Saloranta's related observation of M46 and planetary nebula NGC-2438 by an 8" scope.

Abell planetary nebulae are now sexy. When I got rid of my old home-made telescopes in 2001 and decided to take a break from observing until I could get newer, larger equipment (which turned into a sabbatical of nearly 5 years) the Abell planetaries were not particularly well known, nor sought after by visual observers. Looking back at the resources I used to use in the late eighties, I find that absolutely none are mentioned in the otherwise excellent book "Observing the Constellations" by John Sanford; and I find only a couple of Abells -- galaxy clusters -- mentioned in the index of "Deep-Sky Wonders", a compilation of the monthly columns by the late Sky & Telescope writer Walter Scott Houston. Why were these objects overlooked? I think there are two main reasons: until very recently, few amateurs had taken pictures, and before the Palomar and UK sky surveys were on the Internet, images were largely unknown and obscure; and secondly: there has obviously been a huge leap forward -- even in the face of encroaching light pollution -- in the achievement of visual amateur astronomers. The natural tendency of many advanced hobbyists is to "break new grounds" and to push their senses to the boundaries of experience. With so many spectacular telescopes now in the hands of observers, coupled with the opportunity to "brag" (err...perhaps one should say, nicely, 'to share') experiences in the numerous Internet forums, the Abell objects (both the galaxies, and the planetaries) are becoming known at last, outside the community of professional astronomers.

Before I purchased my new C-11 and 10" Dob in the summer of 2005, I did not even know about the existence of the "Medusa" nebula. Somewhere in my perusal of star charts and software, magazines, and Internet discussions, I came upon it and found, to my surprise, that it was indeed plotted on my Wil Tirion-Roger Sinnott Sky Atlas 2000.0 (but under the listing from the Perek & Kohoutek catalogue of planetaries.) The object suddenly loomed in my mind as not merely one of countless obscure things I'd never seen, and probably wouldn't seek, but rather as a MUST-GET acquisition!

In the third week of January 2007 two events drove me at last into action. First, I happened to notice that the "Medusa" nebula was mentioned in the BBC magazine Sky At Night (Jan. 2007 issue, p. 50, in the "Stargazing Guide" under objects for "Large Scope"); and second, I received a nice email from my cyberfriend Jaakko Saloranta, a remarkably skilled Finnish deep sky observer, who had managed to spot the object at home in Rajakylä, Vantaa, Finland using his 8" f/4.5 Dob. He wrote to me that "Having had such great success with IC 405 which is usually considered some sort of a challenge I wanted to test something else. I found the spot [where] I thought Abell 21 was but saw nothing. Attached O-III filter, swept the region @ 60x... suddenly two very faint, elongated spots flashed in front of my eyes. I did this again and again until I was certain of what I saw. So, saw it but not really that impressive since the last time I bagged it with my 3" from Tenerife. Impressive was that I found it without any maps only with an idea of how to find it based on a mental image 3 years back."

As usual with most of my first observations of new objects, I did not prejudice myself by looking at a deep exposure picture. I examined only the careful drawing made by Jaakko, under his suburban sky with naked eye stellar magnitude limit of about 5.5 optimum. This would probably be slightly worse light pollution than the conditions I could expect on a good winter night at "my site" in the mountains south of San Jose. Jaakko's sketch registered only two unconnected patches; perhaps I could do better with 2 more inches of aperture and a higher elevation.

Depending on exactly what reference source is used, the Medusa nebula is given an official diameter measurement of approximately 12.5 by 10.5 arcminutes: problematical for visual observers, as it has a "mean surface brightness of 16.36 magnitude per square arcminute": this means that despite the visual magnitude figure of 10.2 (similar to many Messier objects) the Medusa is infinitely fainter to the eye, being spread out so much -- and consisting largely of the reddish radiation of ionized hydrogen.

Just after midnight on the morning of Tuesday 23 January 2007 -- the day I am composing this account -- I turned my 10" f/4.7 Orion Dobsonian reflector telescope onto the proper star field, not too hard to locate about 12 degrees to the NNE of the "Christmas Tree Cluster" (NGC 2264) in the neighboring constellation of Monoceros (one of winter's loveliest celestial delights.) Two fairly bright stars point right at the nebula from due south, about a half degree away: SAO 96935 (Mag 8.1) and SAO 96937 (Mag 6.6); almost equidistant on the northern boundary there is a distinctive arc of three stars (SAO 96941, Mag. 8.3; SAO 96929, Mag. 8.5; SAO 96924, Mag. 8.6); and just to the NW by slightly more than a half degree separation is a sparse 8th-magnitude open cluster, NGC 2395 (which, in a large scope, is not especially distinct due to the plethora of faint field stars in this rich region.) About 1.5d to the NW there is a large, faint nebula (LBN 891) that is an even greater challenge than the Medusa, and a little more than a degree to the south, there is an interesting faint cluster: Dolidze 26, adjacent to 4.9 Mag. SAO 96952: so, there is a lot to look for here, even if you fail to nab the planetary.

But. fail I most certainly did not! Expecting it to be enhanced by a filter, I had already installed my 2" UltraBlock (UHC-type) filter in a 42 mm wide angle 2" barrel ocular (too large an exit pupil, but giving me a chance to survey the entire scene all at once) [28.4x at a 2.4d FOV]. It was immediately apparent that the nebula was there; but I had to get my exit pupil situation to conform to my aging eyes, so I quickly changed to a 32 mm Plössl [37.5x. 1.4d FOV, 6.8 mm exit pupil]; but this particular ocular -- an Orion "Sirius" model -- has such uncomfortable eye relief, made worse with a filter, that I was immediately dissatisfied, and sought my better Orion "Ultrascopic" 25 mm Plössl [48x. 1.1d FOV, 5.3 mm exit pupil]: perfect! I recorded in my notebook that this combination gave me the best overall view and image brightness: the nebula was a big, distinct fuzzy "blob" festooned with innumerable, extremely faint, field stars. Taking out the UltraBlock filter, I could perceive the nebula but not nearly as distinctly: it seemed to shrink to half the diameter. I also installed my OIII filter and decided that it gave me even better contrast between the glow of the brightest part of the nebula and the average field background; and I could trace out the object's extent even better, though at a slight loss of maximum brightness, when I switched to my Orion Stratus 21 mm eyepiece, plus the OIII filter [57x, 1.2d FOV, 4.4 mm exit pupil], which is often my choice for high contrast, sharply clear views at moderately low power. Impressed almost to the point of gasping with pleasure, I gave the object my highest rating (four exclamation points: !!!!) and wrote, "With filter, almost like looking at a bright Messier object: spectacular and amazing!"

In my 'patented Waldee imprecision' I drew a couple of eyepiece sketches, not for accuracy but mostly just to check against a picture at home, later. The first one -- very crude -- was restricted to the bright central region (at left) but gradually I began to suspect that there was more to the nebula, and drew it again with the 21 mm Stratus, now showing a slightly irregular arc with densest portion approximately to the north (image at right); when I checked these the next morning against a good image found on the Net, I was ecstatic: for I had seen essentially the whole object, not merely the two disconnected "blips" picked up by Jaakko's smaller scope in a somewhat less dark sky. The first of many images that I found on the Net was this one by Alan Chen, done with a Meade 12" SCT: a stack of 20 four minute frames, with a color registration that suggests that, if it's accurate, there may be a significant oxygen component in addition to the hydrogen alpha (which is why the OIII filter seems to help the nebula visually.)

There are numerous excellent amateur images on the Net. I like these especially: a view in h-alpha light, registered during the full Moon (!) using a 1-meter Cassegrain telescope by Anja von der Linden; and a "collaborative effort between Dave Jurasevich and David Held, sharing data acquisition and processing tasks", achieved with a 12.5" RCOS Ritchey-Chretien. This particular picture is specially interesting because it shows the blue central star (16th magnitude) that I did not even attempt to try to pick up: was I too easily discouraged by its dimness? (It might possibly be detected with my C-11, judging from past experience with other planetaries.) Drawings of the object can shed different light on it than such amazing photorealistic images: you should see the work of Bill Ferris and Iiro Sairanen.

How difficult is this object to be able to see? Well, if we can judge from this report (registration required) by "AstroDawg" (the nickname Steve Gottlieb uses for the ASTRONOMY magazine online forum) of an observing session at Lake Sonoma, Ca. on 1/3/07, "in the finder I confirmed an earlier 80mm sighting of the Medusa Nebula (Abell 21) using 13x and OIII filter. This was not a difficult observation with averted vision." It was not clearly visible in my 9x50 finder but perhaps the prevalence of a lot of faint stars in the spot, plus some of the nebulosity, made its exact location look a little distinctly brighter than the surrounding region.

Finally, the most inconsequential question of all regarding this object: who the heck nicknamed it "Medusa"? I searched high and low on the Net, turning up various pages with fanciful astronomical monikers (such as this one) but none that carried a specific attribution.

0.5/2 degree finder: upright, correct

• My later report of detecting Abell 21 on 2/8/08 using a 4.7 inch (120 mm) aperture refractor.

• Link to Jaakko Saloranta's observation by means of an 8" Dobsonian scope.

Does "LBN 891" actually exist? I'm sure of it; I've seen it!

Yet, if you consult certain highly regarded star charts, you won't find it. According to friends who use the software, it is not included in the database of "Megastar"; and though it appears onscreen in "GUIDE", when you click on the object for information, you are told that according to the "Nebula Databank" put together by Eric-Sven Vesting, it is probably non-existent. (Vesting appears, my research indicates, to be an amateur astronomer and astronomical product salesman with astro-shop in Hamburg, Germany.) Yet, the object certainly shows up if you plot it by means of the Deep Sky Browser.

I viewed this nebula on the same occasion as the session that yielded my observation of Abell 21, the "Medusa" nebula, described above: after midnight on the morning of Tuesday 23 January 2007 at "my site". I had prepared a chart for the Medusa, using the Deep Sky Browser page. When I used that website to create a wide field finder chart for Abell 21, it showed also LBN 891, about 6 degrees to the NW of the Medusa. Placing my 10" Dob onto the field is easy to do as one merely locates three bright stars in a row, the nebula being slightly to the north of the middle star. These are, from east to slightly southwest in a line extending about 2d 22m, the following: 54-Lambda Geminorum (SAO 96746, a brilliant 3.6 mag); 51 Geminorum (SAO 96638, 5.3 magnitude: the central star of the three that is inside the southern border of the nebula); and 45 Geminorum (SAO 96535, 5.6 mag.) The nebula is a huge 2-degree patch extending north of the central star; it might show up best at low power in a rich field type scope in a very dark sky, aided by a filter. In my case, the sky brightness had some degree of light pollution, with an approximate naked eye stellar limit of perhaps something quite close to 6 or very slightly brighter; but the sky's transparency was exceptionally good at my high altitude, the weather being perfectly clear with high barometric pressure.

First I looked with my 42 mm wide field 2" barrel eyepiece (similar to an Erfle) which, in my 10" scope, yields a huge field of 2.4d, at 29x but with an over-large exit pupil. The glow was apparent though it was hard to distinguish it clearly from faint field stars that might confuse the observer. So I switched to a small exit pupil and higher magnification, settling on my favored Orion "Stratus" 21mm ocular, plus UltraBlock [57x, 1.2d FOV, 4.4 mm exit pupil], in the best range for maximum filter efficiency. A very distinct glowing patch was much more densely noted above the average background, and I did my best to draw a sketch. Judging from that, the area that was brightest was perhaps a half degree in diameter. Using the filter made a dramatic difference in its visibility.

I was satisfied, but the next morning at home, when I began to do research about the object, I became immediately perturbed. First, Jaakko Saloranta emailed me that Lynds 891 did not appear in his computer star chart program at all: he uses "Megastar", considered to be the ne plus ultra for data inclusion. I checked with another friend who has the Project Pluto: GUIDE; in version 7, LBN 891 is indeed plotted. But the text information stipulates that Eric-Sven Vesting doubts its existence! I sent him an email requesting clarification about his evidence and conclusion, and received this reply a few weeks later:

Dear Mr. Waldee,

you have reached the right person, but I must admit that i can not recall the [decision] I made 10 years ago. I have used the DSS (100 CDs) and the ''Atlas Galaktischer Nebel''. A deep CCD image with todays equipment should be able to solve the mystery [easily].

Clear Skies
Eric-Sven Vesting

The Deep Sky Browser page (link given above) for LBN-891 clearly shows its existence; so I downloaded all the Digital Sky Survey pictures to see what information could be perceived. As received, nothing but stars showed up; and there was a huge difference in the relative brightness of almost every one, making exactly similar processing impractical. But in my usual method, I applied iterative steps of contrast enhancement until the maximum apparent contrast range was evident to the eye; and I tested them in both positive and negative modes. The blue and red UK plates both showed nebulosity, the red plate appearing to have somewhat more density and distinction.

I next downloaded a one-degree region centered on SAO 96638 from the UK/Schmidt red plate, enhanced and cropped it, and adjusted the orientation and angle of my eyepiece drawing to have the same aspect for the purposes of this comparison picture. SOMETHING is there, indeed! The region of what I perceived as densest, brightest nebulosity, northeast of SAO 96638, shows up as being a grayish-whitish irregular patch in the heavily processed version of the red exposure, shown to the immediate right of the sketch.

The original Palomar Schmidt plates yielded some nebulosity, and the brightness situation seemed reversed, with MORE on the blue plate than on the red. How much of the difference is due to an overall gamma disparity; variable sky conditions; hypering, or other factors? One cannot know for sure from THIS limited experiment; and it might also be necessary to examine a very wide region of, say, several square degrees to see the nebulosity variations, not practical by means of DSS downloads. However, it tends to corroborate the value of color in the original catalogue, favoring the blue. How were these evaluated, and by whom: who was "Lynds"?

Now it was necessary for me to get some deep background on the subject. I first obtained the original Lynds catalogue, as published in 1965 in the Astrophysical Journal: you may get it in PDF form at this link. I read the entire paper by Dr. Beverly T. Lynds, in which she explains how the original Palomar sky survey plates were examined, with isophote maps of new nebulosity regions measured and marked, avoiding known ones (including recent planetary nebula discoveries by George Abell.) I noted particularly that she states:

There are many nebulosities having the same anomalous appearance on the Palomar prints. As their surface brightness decreases, their identity is lost, and a casual glance gives the impression that these objects mey be produced in the developing and printing processes. For this reason, some of the reject plates of the 48-inch collection were examined...The author is convinced that with a faster camera, of about the same scale, many more such nebulosities would be detected--objects of very low but relavitely uniform surface brightness in the red (103a-E) and blue (103a-O) photographs of the area.

Those 103 numbers refer to the old Kodak glass plate film emulsions used in the forties and fifties for astronomical pictures, standard types that were employed at professional observatories and used in the Palomar Sky Survey. I have looked at original 103 type plates, and earlier ones, at Lick Observatory and can testify to their detail and beauty if exposed after correct hypersensitization and in a very transparent sky. The online scans of the Digital Sky Survey really don't do justice to them, nor even to the large scale transparencies of the POSS that I have also examined at Lick Observatory back in the middle 1990s.

Furthermore, the files I obtained online were in GIF format, not the preferred FITS (as I don't have any really good FITS processing programs on my computer, the freeware stuff being of rather poor quality, producing images that look worse than the GIFs.) The Graphics Interchange Format (GIF) yields only 256 levels of luminance or color gradation, and according to this article, "is not suitable for photographs, half-tone images and other pictures in which you need a fine gradation of color rather than definite boundaries between different colors." It is lossless, but only because it contains a relatively small data set that is easy to compress and recover. My guess is that there is a definite loss of luminance detail at the low end, occurring at the first step of data scanning acquisition or maybe in the GIF conversion. Furthermore, Beverly Lynds examined the original plates as well as "rejects" in order to confirm some extremely faint nebulae. Perhaps persons who try to second-guess her professional work, but by using inferior online sources, are simply not able to gather sufficient accurate data.

As before in my work to confirm a nebular patch near Abell 7, discussed earlier, I found a situation where nebulosity showed up distinctly on the UK Schmidt DSS plates though poorly on the older Palomar ones. This could be due to a number of factors, including superior sky darkness in Australia and later developments in hypering and processing. So, since the nebulosity of LBN 891 does show up on both red and blue UK plates, I consider this a confirmation of Dr. Lynds' plotting of the object -- and it seems to be quite visible to the eye, at least at "my site" and under the conditions I've described.

The Lynds catalogue is quite well known, but who was the original investigator? It is Dr. Beverly Turner Lynds, now retired and living in Boulder, Colorado: not exactly a luminary in the astronomical world but a well known, respected, and solid researcher. According to a brief and slightly out-of-date biographical note found on this page: "Dr Beverly T. Lynds served as Assistant Director of the Kitt Peak National Observatory in the years 1976--1978, and in 1988-89 was the Scientific Assistant at the IFA, University of Hawaii. She [became] Program Director of the project SKYMATH [of the University Corporation for Atmospheric Research]. Dr Lynds edited the book Dark Nebulae, Globules and Protostars dedicated to Bart Bok." There are numerous links to her name on the web, but most are out of date. She apparently now lives in Boulder, and is presently retired; in 1987 she married astronomer Leo Goldberg, who was the director of Harvard College Observatory in the 1960s and became director of KPNO in 1971. Unfortunately, he died less than a year after his marriage, in Nov. 1987: see this article about him, which mentions his wife Beverly. There is also an interesting webpage article about rainbows, written by Dr. Lynds when she was with the UCAR. This webpage links to her well known "ATLAS OF DUST AND H II REGIONS IN GALAXIES": in numerous cases -- such as, notably, for NGC 5194, 157, 3527, and 6118 -- she has done sketches of galactic dust based on her examination of photographs, an interesting connection with the practice of visual astronomers in the era before photography.

After exhaustive searching I finally located a link to a picture of Dr. Lynds, taken at a conference. It is on the NASA Godard web page but the server was slow in responding so I could never bring it up. After trying numerous times over the space of several days, I got the page once and saved the picture. I placed the link in this article -- the website is here -- but afterwards I checked it numerous times and found that it was almost NEVER working. So I have cropped the larger picture of Dr. Lynds and include a "fair use" excerpted version of it here, since the government server doesn't seem reliably able to provide it.

Using what seemed to be the last known email address of Dr. Lynds, I composed a long email requesting background information on how she confirmed the faintest of the objects in her catalogue, and asked if she had a chance to compare the online DSS pictures with her recollections of the originals. Unfortunately, it was immediately bounced back to me by the mail server: "addressee unknown".

Investigators who would like to know more about these objects, and who are amateur observers, will find her original paper containing the catalogue to be a bit frustrating, for it is not ordered by the "Lynds numbers" that came later. The objects are listed in order of the galactic coordinates: thus the object now called "LBN 891" is, in her original, "200.10+11.99". In the paper, she gives its angular dimensions (120 by 120 arcminutes), area (2.76 square degrees), apparent color ("1" -- i. e., shows up on blue plate); relative brightness ("6" - barely detectable), and equatorial coordinates J1950. She also specifies that it is an "isolated region" and not associated with other nebulae, in the ID column. An ASCII text file version of the catalogue that conveys the current LBN numbers may be found here; this particular file is used by the GUIDE program for plotting, after precession to the current coordinate epoch. (I have also created my own page of Lynds bright nebula cross-references, adapted from the original catalogue, which you may access here.)

One other anomaly remains to be resolved: the issue of my being able to see the object better with a UHC type filter, even though according to the original Lynds catalogue data, it is considered to be more blue than red, ergo more likely a reflection than an emission nebula. Is it both? Sadly I don't seem to have recorded in my logbook a specific test with a SkyGlow LPR filter, which helps reflection nebulae (though it too will improve the contrast of emission objects: not a conclusive test.) A spectral analysis is needed, and one does not seem to be available to judge from the paucity of information about LBN 891 that turned up after two days' searching on the Net. This is truly an obscurity, and as such is probably worth investigation by advanced amateurs who'd appreciate a challenge!

UPDATE: My friend Jaakko Saloranta, who hasn't yet been able to look for the nebula (nor have I, since weather is now bad a few days after I spotted it), has done his own independent study of the Palomar red and blue plates, using heavy processing in Photoshop 7 (likely better than my cheap graphics editor called "PhotoStudio.") We seem to have come to the same conclusion: that the nebulosity does show up better on the blue than the red plates of the original Palomar survey, the ones used by Lynds; but he determined that this may also be the situation with regard to the UK plates, reversing my finding and, if correct, corroborating that the nebulosity has short (blue) rather than long (red) wavelengths. Jaakko has spotted regions that might stand out, including "a faint, irregular blob N from 51 Gem with (N-S) size about 0.7deg so quite large." He also opines that "it is there, but no wonder it is listed as 'probably non-existent' as it is so faint. This kind of high galactic nebulosity would get cropped from several lists, including the DSH's and MegaStar." He cautions me that my sketch may be inadequate and to make sure that one avoids being misled by glow from stars as "The area you sketched as the nebula, has several 10th magnitude and fainter stars that I'd consider to appear as nebulous with filters and small magnifications. Is this what you saw? No, I don't think so... The area, N/NE shows the same kind of 'blob' of faint nebulosity both in your sketch and in the POSS2/Blue plates. The size (I just measured it again from a Blue plate, centered on 9th magnitude GSC 1346-1012) is at least 60' x 55' so it pretty much covers the entire 60' x 60' field."

Jaakko has marked two regions: labelled "Area 1" (where I felt I could see nebulosity, which tends to be corroborated by the picture) and "Area 2" (which has a dense grouping of similar stars that could fool the eye into believing it was a nebulous patch.) His screen dump of the result, plotted by means of Megastar, is here. He suggested that "Area 2" would would serve as a test to determine what could be seen by eye, since this particular region does not show up on the Palomar plate as having significant nebulosity. If it looks clear by eye, while Area 1 still does look nebulous, "you've passed the test" and the nebulosity is really being seen. Thanks, Jaakko! And, for what it's worth, I've tried several times recently to test the assertion that filters 'create' spurious nebulosity under certain conditions, and as far as my equipment, eye, and viewing environment are concerned, I don't seem to perceive this as a repeatable problem.

0.5/2/4 degree finder: upright, correct

Messier 44, "Prasepe Cancri", is of course an object that is visible to the naked eye most anywhere outside a major population center, if one has learned the very rudiments of how to search for it. Why bother to include it in an article about particularly faint, obscure "fuzzies"? The answer is, of course, that for some perverse observers -- such as yours truly -- the object is an annoyance, because it makes it especially hard to see the galaxies that are along our line of sight, far beyond it!

I was not particularly conscious of the challenge of looking for them until the subject was recently brought up in an email I received from Jaakko Saloranta, a deep-sky observer who lives in Finland. It is a particular joy of his to make difficult observations: with VERY small optics; by naked eye; of extremely faint stuff. Since Finland is not exactly the Nirvana for year-round astronomy, he also observes in far southern climes, near the equator. His website contains numerous superb and accurate drawings, and lists of the many fantastic and obscure objects he is seeking, or has already achieved. We can start at his page featuring naked eye observations of M44, plus a wide field drawing done with a small refractor. Jaakko tells me that he sometimes spends hours making his detailed star field sketches, carefully scaling, plotting, and placing each visible star. My sketches are often laughably inaccurate, of use -- sometimes only vaguely -- to me later at home for checking something on a photograph. Jaakko's drawings, however, are often so good as to be useful as REFERENCES.

When I learned from him that, now, some advanced observers were making a special project of 'sweeping up' the galaxies visible in the interior region of M-44, I jumped at the opportunity to do so myself. Since getting my C-11 and 10" Dob in the summer of 2005, both scopes giving me a leap in limiting magnitude compared to my old 8" instrument, I have been attempting to see how faint I could go with them, primarily with small angular diameter, faint galaxies. I've reached about 16.3 magnitude or so with the C-11, and perhaps somewhere around 15.4 to 15.6 with the 10".

The problem is, of course, that "visual magnitude" is still not a well defined and universally controlled parameter. We have inherited lots of flawed magnitude measurements from the days of the visual astronomers whose work was compiled into the NGC; and recent 'photographic' galaxies, found only on deeply exposed plates done by large observatory telescopes, often have no visual magnitude rating. There are general conversion factors that may be used; but much adjustment is often required. The larger the object of a given visual magnitude, the harder it is to see with a telescope: because the light is spread out over a wide area. Well, then: why not use "surface brightness"? There are arguments against that, too: especially in relation to galaxies. So, let's just be somewhat imprecise, and generalize that galaxies fainter than a nominal 14th magnitude are indeed very dim and difficult to see. They don't look much better in a 20 inch scope than a 10 inch one: just specks of light, with very little detail seen, if any. Every time you increase your telescopic aperture by an inch or two, you see more... and more... and more of them. But, the only real satisfaction is just being able to check them off, one by one, and take some glum comfort in that repetitive task. As far as getting a real sense that you are staring at an isolated, distant, unapproachable "island universe" which MIGHT have intelligent creatures, planets, and astronomical wonders: you don't get that by seeing, with averted vision, a speck of light that is not much more distinct than a "floater" inside your own eye.

This is, then -- I have to admit -- the end result of a galaxy-quest in the region of M-44. I do it because I have a constant, gnawing craving to observe Galaxies Almost Too Faint to See®. (Perhaps I should write to Meade or Celestron to see if they'd like to use that slogan.) I do it for the same strange reason that I once collected 13,000 classical Lp's. I do it following the same impulse that has now led me to buy almost 10,000 compact disks (my friend Rich once made a face and grimaced when I told him about my latest purchases: "Waldee," he spat derisively, "you collect Mozart CDs by the YARD!") I do it because... perhaps because of a childhood potty-training deficiency (as a Freudian astronomer-psychiatrist might assert.)

I have only recently begun the project of going through the "nearly nothings" that comprise the galaxies in the immediate coordinate region of M-44. I've only been at it for part of one observing session, using my "backup" telescope (the 10" f/4.7 Dob), not the preferred GOTO C-11 that can be aided by a star chart to position itself closely to a desired target, and which has much less tendency of light scatter from the bright stars of the cluster. The Dob is, comparatively, a drag to use; and after an hour and a half of struggling to keep it just on a particular field, one is totally frustrated and exhausted. I'd rather do this with the C-11 and will, as soon as the weather permits.

I shan't do all your work for you. I intend here merely to list the galaxies that I am currently trying to spot, down to somewhere in the range of 16th magnitude visually (though some are rated only photographically.) You may make up your own chart using the Deep Sky Browser, as I did, and go to each of the objects in the links below to get their coordinates and whatever pertinent information is known about them (in some cases, very little.) [NOTE: See updated sections below; I've changed my mind and have produced a detailed chart given at the end of the article, which you may download; and have observed almost all the objects plotted on it. -- 3/27/07]

Since M-44 covers such a large expanse of sky -- about 95 arcminutes angular diameter -- it was difficult to download the entire object by means of the bits and pieces necessary using the Deep Sky Survey pictures; the one shown above was produced by NOAO/AURA/NSF, and doesn't show the faintest objects. I have made up a deeper image, here, based only on a 45 arcminute diameter from the DSS resources. There are galaxies way beyond that which are worth seeking; four show up in the immediate interior near the center of M44, which I have highlighted somewhat by subtracting the red plate data from the blue plate data of the UK2 survey picture, after making careful adjustments of the contrast of each picture. This diminished some of the star image data; the galaxies may appear a bit more distinctly by this means. I suggest that you create as large a chart as you can, such as this one I've linked to in the Deep Sky Browser. Zoom in until it has plenty of detail. It might not necessarily have all the labels required, so you must do some further detective work. For instance: on my first try, the edge-on spiral UGC-4526 didn't show up in the chart; I discovered its existence later, and went back to the Deep Sky Browser and hunted specifically for it.

On the early morning of Tuesday 23 January 2007, starting at midnight, I began the struggle to see some of these objects with my 10" Dob. The first thing I had to avoid was as much light scatter as possible, since some of the bright stars in the cluster range from 8th or 9th to 6.5 magnitude. Immediately I rejected the use of one eyepiece: my Orion "Epic" 3.7 mm, which has off-axis reflections if stars get slightly outside the FOV. But, I needed high power to be able to restrict the field, get as many bright stars as possible out of view, and distinguish faint, narrow angle objects. I found myself using a 6mm Plössl plus 2x "Shorty" Barlow [400x, 7 minute FOV, 0.65 mm exit pupil] , which worked quite well, maintaining a dark reflection-free background. By this means I was able to verify NGC-2643, which I rated as "VVF, near invisibility but just barely seen." NGC 2637 was even more difficult. I had to try to judge the exact angle relationships and positions with respect to the star field, but when I looked right at the expected spot... nothing. Finally after much frustration I allowed the field to drift across my eye, several times, not moving the scope until the nearby stars were well outside the eyepiece. After several tries, I decided that the galaxy was seen: just barely, at the threshold: "VVVF". Then I went for IC-2388, which was discovered by Edward Barnard. It rated only my inconclusive remark: "possibly. Ext F! Averted vision."

I moved to the western edge of the cluster and had no special trouble locating the somewhat brighter NGC-2624. I am dismayed to have to tell you that according to my notes, these objects required 1 hour 30 minutes elapsed time to locate and to claim to have been barely perceived. At this point I had at least one more relatively obvious object to pin down: NGC-2625. But, I was so fatigued and frustrated that after ten more minutes of struggling, going back and forth from high power eyepiece view to 9x finder, and to the chart, that I just collapsed! It was useless; my brain had deteriorated to jelly, and I began to have trouble focusing my eyes. At least, I may have gone to the visual limit of the 10" scope under the present sky conditions (perhaps NELM of 6th magnitude, on what I consider a "good" night at my site in the mountains.) But, it was time for a break; a snack; and to put on a different symphony. I took a much needed ten minutes off, and relaxed...

This project will have to wait for a night with the C-11. My difficulty with NGC-2625 was that the chart I'd prepared had the galaxy's isophote right at the edge, showing absolutely no field stars for triangulation. It was too faint just to pop into view without knowing precisely WHERE to look for it.

How do my 'betters' fare? Here is a good example, taken from a recent post made by Steve Gottlieb to an Astronomy Magazine observing forum (registration required.) I quote it in part:

Beehive Cluster galaxies: Yes, there are a number of faint galaxies hiding among the bright stars of the Beehive (M44). Bill and I confirmed our observation of 8 of these elusive galaxies. Five have NGC numbers, 2624, 2625, 2637, 2643, 2647) and were discovered by Albert Marth using a 48-inch f/9.4 reflector from Malta (see http://www.klima-luft.de/steinicke/ngcic/persons/marth.htm to have a look at this behemoth scope). With some effort we also identified CGCG 89-056, IC 2388 (discovered by E.E. Barnard) and UGC 4526. The easiest of the lot are the pair NGC 2624 and 2625 on the west end. NGC 2624 was described as "fairly faint, small, round, 25" diameter, weak concentration. A mag 15.5 star is close SW. Brighter of a pair with N2625 located 3.2' ESE. Situated on the NW edge of the Beehive cluster." My notes for NGC 2625 read "faint, very small, round, 15" diameter. Smaller and fainter of a pair with N2624 3.2' WNW, though the difference in brightness appears less than the 1.4 magnitudes listed in catalogues." This was using 280x in my 18-inch (7mm Pentax XW).

A lot more experience, and more aperture, tell the tale. But, I'm not finished yet! Below is a table of the ones that I have plotted. When THOSE are finally acquired, I'll go for more! In the column of "Designations" the galaxy names are hyperlinks to the appropriate Deep Sky Browser page so that you may easily obtain coordinates and more data.

IC-2388 Boy, is this one faint! Further attempts to confirm it visually have been "iffy". On 3-17-07, with my GOTO C-11 telescope, I zeroed in precisely on the position, confirmed with a printout I made of the chart given at the end of this section. I wrote that it was detected but "seemed to be about 30 arcseconds to the W of the position charted by TheSky version 6 -- can this be right?" Or, was I suffering from an illusion, since the galaxy is SO faint? (The program GUIDE shows IC-2388's declination as being 20 seconds less than the value given in TheSky: could this account for the discrepancy, which I might not have precisely judged by eye?) On 3/16/07, I tried at 1am using the C-11 and gave up by 1:20, writing "No! Sky transparency, seeing getting worse." But on 2-24-07, using my 10" Dob, I felt I could definitely see it, using an earlier chart prepared from the Deep Sky Browser page, writing that it was "barely detected, at threshold using averted vision, 1:20AM, 10mm [Orion Sirius] Plössl + 2x [Orion Shorty] Barlow" [240x, 12 min FOV, 1.05 mm exit pupil]. So, counting the suspected viewing of 1/23/07, perhaps I can rack up at least '1-1/2' sightings, and consider this one accomplished. One really comes away from this experience with increased respect for Barnard's acuity, as well as a fatalism about experiencing dark skies similar to those of more than a century ago.

ZWG 089.056/PGC 24284 On the same date as immediately above, 2-24-07, with the same scope and magnification, I believed that I detected this object, and wrote that it looked like a "Fuzzy, near stellar-spot, fluctuating". On 3-17-07, with the C-11 telescope, it seemed to be somewhat more definite: "Something there -- very amorphous, low surface brightness. 9mm Expanse [311x, 12 min FOV, 0.9 mm exit pupil]; saw various 'lumps' with 6mm Expanse [466x, 8 min FOV, 0.6mm exit pupil]. On the night of 3/15/07 using the C-11, I wrote that at 10:02 pm "I got it! 3.7 mm [755x, 4 min FOV, 0.4 mm exit pupil]. Zeroed in on field. AV [averted vision]: oval faint blob, EEF." The seeing was excellent; an hour earlier I had split HR 3701/STF 1338 (a nearly equal-magnitude double, measured at 1.0" separation in 1999.)

ZWG 089.062/PGC 24335 On 3/15/07 at 11:33pm, I saw it with the C-11, writing in my logbook, "Took an hour! Tried 15mm, 9, 6, 10+2x Barlow, 7.5 epcs, the 9.5 mm gave faintest *s [294x, 10 min FOV, 1.0 mm exit pupil]. Along a line from GSC 1395:1841 (11.8 mag) past GSC 1395:2631 (15.4 m) for another few seconds. Fades out to inv." Then, at 11:45 pm: "Got it more consistently with 7.5 mm [372x]." Finally at 12:05 am, "Best w/6mm [466x]. Almost steady now, a general glow < 1' dia, sometimes get the faint * next to it [GSC 1395:2931, 14.6 m]. I also have an observation logged with the same scope on 3/17/07 at 1am: "May be a few arcseconds to E of a ~14m *." So, I'll consider this object observed.

PGC 24400/UGC 4526 Same date, scope as above. "Not too hard. F, cigar shape but not distinct; used averted vis., 9mm Expanse [311x, 12 min FOV, 0.9 mm exit pupil]; ~15th mag * in it?" This is one of those ambiguities of the Guidestar Catalogue that I'd need to know more about to figure out for sure. GUIDE shows a nice narrow isophote plot, with a green dot near the very center, which is identified as GSC 1395:2000, mag. 13.8, "non star: 2". Yet, TheSky v. 4 identifies it as "Non-Stellar 3" at mag. 14.9! And, that program does not show a galaxy isophote, nor plot the galaxy at all. To confuse the issue further, TheSky v. 6 plots the galaxy, but shows in the EXACT center, a star labelled GSC 1395:2008, mag. 14.3! On the previous session of 3/16/07, using the C-11 I wrote that the galaxy looked like a "Faint spindle ~1' thin to left of faint * GSC 1395:2029 (14.8 m). With 7.5 [372x] VF but pretty well seen, AV." I believe this confirms that I did see the galaxy visually, more than once: so, again, call it observed.

IC-2390/NGC 2643/PGC 24434 According to the information page for this galaxy on the NGC/IC Project, quoting Dr. Harold G. Corwin, "NGC 2643 = IC 2390 This identity, first suggested by Reinmuth, was taken up by RNGC. The object was found by Marth in 1864. Correcting his position by 18 seconds of time and 11 arcmin leads to IC 2390. The IC object matches Marth's description, and there is no other object in the area (the east edge of the Beehive) that would fit better." But on the same page there is a longer commentary by Malcolm J. Thomson, pointing out other difficulties with Marth's observations of three "new nebulae" that same night. (This page cannot be directly linked here, but you may find the information by surfing to this link and typing in "IC 2390" in the dialogue box for NGC/IC designation.) The DSS picture provided shows only ONE galaxy at the current accepted coordinates, and it clearly has an edge-on depiction as seen from the Earth, with a center bulge. Steve Gottlieb's observation is given: "17.5": very faint, very small, round, 15" diameter. Located 1.2' NW of a mag 11.5 star on the eastern side of M44. Several brighter stars in the 22' field at 220x." I am confident that I have now seen it. My own observation, C-11 telescope on 3-17-07, states that it was "EF! [extremely faint] Small spot w/9mm [311x, 12 min FOV, 0.9 mm exit pupil] & maybe 7.5 barely [Orion Lanthanum ocular, 372xm 8 min FOV, 0.8 mm exit pupil]. Better seen while slewing scope slowly across field." My eyepiece drawing shows the galaxy and three stars in the field that agree, correcting for my scope's image orientation, with the DSS picture. Done!

NGC-2624, 2625 On 27 January 2007, using my 10" scope and a chart made from the Deep Sky Browser, I had observed NGC 2624, definitely. But I gave up at that point, my chart not covering the guide stars at the edge of M44 near 2625. On 3-17-07, I was using a superior and more detailed chart -- given below so that you too may download and print it -- and found both these galaxies with relative ease using my C-11. 2625 was a "Very small round patch, fading in/out with 9mm [311x, 12 min FOV, 0.9 mm exit pupil]." 2624 "seems larger, can see straight on and hold, 9 mm."

NGC-2647 This galaxy is slightly outside the "official" boundary of M44, about 40 arcminutes to the SE of the exact center of the cluster. This galaxy was spotted by me with the C-11, as above, and described as "something involved with ~13.5M * -- hard to tell shape and PA. 9mm, and possibly seen w/ 7.5 mm" [Orion Expanse and Lanthanum oculars, operating specs given above.] TheSky version 6 shows that the star "involved" is GSC 1396:93, 13.5 mag. But, GUIDE gives two separate measurements: 12.98, and 13.52, and calls it a "non star". TheSky 4 says that it is "13.0" and plots it 36 arcseconds to the SW of the galaxy, while it is shown in the exact CENTER of it, in GUIDE. Go figure...at any rate, I am pretty sure I saw it, so I'm considering this one done.

Moving to the immediate region OUTSIDE of M-44, I secured observations of some nearby galaxies included in my downloadable chart:

PGC 24431/UGC4532 SE of center of cluster, this galaxy is somewhat larger than the other PGC objects, rated at 16.2 magnitude, 1.3 by 0.2 arcseconds, seen edge-on. On the date above with the same equipment, I observed it and wrote, "Definitely seen w/9mm while slewing across field slowly. Larger nebulous patch, varying in visibility," (I meant larger than previously viewed galaxy PGC 24522, given below.) An anomaly to be noted, when using my chart, is that the program which produced it did not use the correct angular diameter coordinate and showed it as being round. GUIDE, and other software programs, plot it as having an extreme edge-on and narrow shape.

PGC 24522 This faint galaxy is about 58 arcminutes to the E and slightly S of the center of the cluster. It is rated at 16.4 (photographic) and at 0.5 by 0.4 arcminutes diameter. Could I possibly see this? Apparently, yes. At above observing session I wrote, "SAW it! Suspected with 15mm Expanse [186x, 21 min FOV, 1.5 mm exit pupil], confirmed w/9mm. By sweeping slowly, perceived oval with decent clarity and definition, but VVF." I don't know how you would calculate a precise visual magnitude for this object, but it would be one of the faintest galaxies I've ever seen with my C-11!

PGC 24188/CGCG89-53 This galaxy is located about 51 minutes from the center of M-44, to the W and slightly S. It is a 16.1 magnitude (photographic) galaxy, with a diameter of 0.6 by 0.3 arcminutes. My logbook of the same session as above states, "Saw, inverted vis., VF * (14th M) which might be on the SE periphery?" This star would appear to be GSC 1936:1740, 14.8 according to TheSky 6, plotted just off the center of the galaxy to the SE but within the isophote; however, GUIDE shows it nearer to the center and rates it at 14.3. Perhaps the brightest region of the galaxy is not the exact center of the longer axis, to the eye. This could indeed be suggested by these pictures, shown in this NED link. And, in the POSS picture (shown as a negative) there is a very faint star next to the longer axis of the galaxy which does not appear to be plotted in the GSC: maybe this is the star that I saw? (The only problem is that if the picture is pole up, the star would appear to be to the NW, not the SE: did I make a mistake when I wrote my description? Possibly.)

PGC 24407/CGCG 120-021/MCG +04-21-013 This galaxy is shown on my downloadable chart in the upper left (NW) corner; its magnitude is 15.2p, and the diameter is a round 0.6 arcminutes, with a surface brightness of 13.8 mag/sq arcminute. My notes state that on 3/18/07 at 3:10am (with the C-11) it was a "Very slight glow between 2 *, one to N fainter - dark sky now, completely fogged in toward Gilroy!" The pertinent Deep Sky Browser page shows something perplexing: it plots the galaxy to the west of the stars I describe, even though the DSS picture shows it between the stars (the northeastern one being GSC 1398:1741, 12.4 mag, the southwestern one being GSC 1398:1959, 11.9 mag.) I cross-checked the object in GUIDE, and found that it too placed the galaxy at the same incorrect spot, about 5 arcseconds to the SW, not between those stars. So I then downloaded the image of CGCG 120-021 from the NED search engine, and confirmed that -- yes! -- I was precisely right in my visual description; the software and website were wrong. (Little discoveries like this tend to increase my own sense of confidence as an observer, I'll admit.)

A galaxy shown in my downloadable chart that was NOT seen during this session was PGC 24315. I wrote "No. Tried slewing across region but not detected." Another questionable one is NPM1G+19.0185, which is -- as you will note from my chart -- very close to ZWG 089.062/PGC 24335. Frankly, I suspected it to be the SAME galaxy (though I didn't feel entirely competent to make that claim, as it is an object from the respected Lick Observatory Northern Proper Motion [NPM] program, and one of the authors of that catalogue, Arnold Klemola, just did me a nice favor last week!) It is plotted by my computer program TheSky 6 at a slightly different location than PGC 24335; but GUIDE does not show NPM1G+19.0185 at all, though it plots PGC 24335. I viewed this region carefully, and saw only the latter object, not the allegedly different "NPM" galaxy at a supposedly nearby location. Then, while researching the matter to edit this webpage, I used the NED search engine and typed in both "NPM1G+19.0185" and "PGC 24335" successively: and came up with the same object name information table and picture! Finally, after writing up the following week my observation report of the obscure galaxy PGC 17232, I learned to use Hyperleda more effectively, and confirmed that -- yes, indeed -- it IS the same object. In perusing the documentation file for the J2000 version of the NPM catalogue, I learned from Dr. Robert Hanson's explanation that "in June 2003, after an overlap comparison with NPM2, we re-calculated the NPM1 transformation (B1950 to J2000) using an improved algorithm." A complex process was used to transform the coordinates; "the new J2000 NPM1 is accurately on the J2000 coordinate system at the 0.1" level or better." That suggests that the larger position error of the spurious location of the galaxy in TheSky is due, instead, to another problem, common also to the database used by the Deep Sky Browser of Mikkel Steine. Perhaps the original year 2000 version of the NPM1 is in use, not the revised and improved version, or some file conversion process has caused a rounding of number values. Indeed, innumerable other small, faint galaxies and nebulae in many star chart programs are not properly cross-referenced and reconciled, and may prove confusing to those of us who see the discrepancies onscreen, differing from what we can see in our eyepieces and in sky images.

In fact, in the chart below, I used the photographic or total B-magnitude for the obscure non-NGC or IC galaxies (with visual magnitude ratings) that I obtained from Hyperleda. If you click on the links, you will often get a different rating (usually fainter) on the database used by Mikkel Steine's Deep Sky Browser. Do these small discrepancies make a real difference? For visual observers, using instruments where the galaxies are just at the threshold of detection: possibly. This could explain why I can see galaxies that are often shown by my star chart program as being "16.3" or somewhat fainter; another catalogue might list them at "15.7" or slightly brighter. Ah, me...

I revised the 'Magnitude' column values on 3/30/07, using a variety of sources: the Steinicke Revised NGC data; the NGC/IC Project; and my own conversions from the total-B or other magnitude given by the Hyperleda search page for the object, processed with a modified version of the Javascript Visual Magnitude Calculator by Matt Oltersdorf. His program -- found here on the net -- as originally written has a cutoff of 16.0 magnitude; I have modified it by changing the source code, leaving the edited file on my own hard drive. The results are interesting and probably not entirely accurate, but in comparing certain galaxies with published v and p magnitudes, it can come close. The galaxy visual magnitudes I have so derived are marked with a tilde (~) to indicate that the value is approximate.

Here is my new chart for locating galaxies seen through M-44 and in the immediate region; the round outline -- 70m diameter according to this particular software program; others say as much as 95m -- shows the outer "official" boundary for the star cluster, and the field width is about 2d 32m horizontal, 1d 26m vertical:

M44 region finder chart: mirror image

• Link to Jaakko Saloranta's observations by means of naked eye, and 3" scope, of open cluster M-44.

I believe that this wonderful planetary nebula should offer most observers with favorable conditions, at least a 10-inch aperture telescope, and an OIII filter, the chance to see a quite obscure object with unexpected clarity and distinctness, not very far removed from a properly- registered monochrome photograph. Judging from the view that I had at "my site", the nebula may be found and perceived in a sky that yields at least naked-eye stars from 5.5 to 6th magnitude; if the sky background is dimmer, showing even fainter stars: all the better. Nearing 2AM on Thursday, 18 January, 2007, I studied the nebula again to confirm my earlier sighting of it on Monday 15 January, and, as usual, went through a wide variety of eyepieces and filters until I had extracted as much as I thought I could perceive, using my 10" Orion SkyQuest Dob. To detect more detail, I'll have to move up to my C-11.

Abell 23 has a visual magnitude of 13.1, a diameter of 54 arcseconds spread across an almost perfectly circular outer halo of nebulosity, and a surface brightness of 12.8 magnitude per square arcminute of area. I am surprised that it was not plotted on the Tirion-Sinnott Sky Atlas 2000.0, considering how well it can be seen with my 10 inch scope (an 8" reflector, and perhaps a 6" refractor, might be suitable if the observer scrutinizes with great care, with little or no light pollution.) The sky conditions that permitted the sketches shown below were indicated in my logbook as "very clear and transparent, but windy" with only the mildest traces of light pollution from the Santa Cruz, California region. I might have seen it even a little better had I done so earlier, just at midnight when it transited. Objects with low declination, this close to my horizon, benefit from all the elevation possible. That I was able to see as much detail as recorded indicates the exceptional, and very unusual, good winter seeing I was experiencing.

On this particular occasion, I was well prepared to see the nebula. During the month of January I had intended to spot several extremely faint "test" objects, including Minkowski 1-18, Min 4-2, two NGC planetaries, and Abell 23: all situated in the constellation of Puppis and considered to be significant challenges. On this very night's observing, I had made what I considered a confirmed observation of M1-18, reported above, which some observers have had trouble seeing in a 20" aperture scope; ergo, my conditions must be considered to have been somewhat exceptional. I had used the Planetary Nebula Finder Page to print out a list report of all the PN's in Puppis, and had also created local area finders for them with my star chart software. Usually, I'm not this well prepared, and just look at objects that are best situated in regions of darkest sky.

When I began to prepare this report for the "Fuzzies" pages, I looked on the Net for prior accounts of visual observations, and was absolutely shocked to discover two observers, quoted here, who both tried to find it, and failed to be able to see it -- using a telescope as large as 20 inches of aperture! Why, then, did it seem so obvious to me? Had I made a mistake? No: my eyepiece view seemed to match the field, if you perform a reversal to correct for my Newtonian's image orientation, of the Deep Sky Browser chart if zoomed to a FOV of about a degree. I correctly plotted the orientation of the five stars that I drew, and the PN in the center. Furthermore, the pencil marking of its position that I made that morning on my Sky Atlas 2000.0 is correctly placed.

In order to confirm all of these indications, I fired up my best planetarium program, created a "FOVI" (field of view indicator) for my 10" f/4.7 scope using the same eyepiece (a 17 mm Plössl employed when making the sketch); set the proper display orientation to match my drawing; and then looked for stars that corresponded with what I'd drawn: yes, indeed, they were there (highlighted here in light orange, and identified.) My drawing matched the sky region and key bright stars in the close field quite well. So far, I could find no mistakes that would indicate I'd looked at the WRONG object. Furthermore, the closest planetary -- PK 248-08.1, about 3d to the east and slightly south -- was one that I had plotted on the same chart, and had looked at on Monday, 15 January, three days earlier, when I obtained my first viewing of Abell 23. I had done, therefore, TWO careful observations of both planetaries, during the same week, with good logbook notes to back them up. I was not in error!

I went searching for other reports, and found on the public net, only one (which, since it was posted to a public forum, I had quoted here in this present article.) However, the observer who made that report wrote to me recently -- through a circuitous route that finally got to me! -- that he had great difficulty accepting my observation as it differed so much from his. So because I respect his very significant experience, I have revised this page and removed that reference. Suffice it to say that observers in very different climates, geographical locations, and altitudes may have very different experiences with tenuous objects (and, please do remember that I am observing at the second highest altitude locale in the south bay area, not too many miles from the remarkably steady air of Lick Observatory.) I have bad observing nights that lack clarity, as well as especially good ones: so when I work on something like a challenging Abell planetary I try to observe it more than one time -- preferably on at least two more occasions -- and with an alternate telescope if possible, before writing up a report for these articles. And I include what drawings I may have made -- if the patient reader is willing to accept them as any reasonable form of "evidence".

Later I found this German webpage of Abell planetaries, collated by Stathis Kafalis. Though there are no links to a verbal description of Abell 23, the list indicates that the German observer and author Roland Stoyan has viewed it with a 14" aperture telescope: the far-right column is marked "Z", which the page's legend signifies as meaning "Zeichnung gemacht" (which in English means "drawing made.") I have found that, generally, objects that are seen in a 14" telescope are indeed quite often visible to me in my 11" and sometimes in my 10", due to the transparency of my high-altitude coastal sky.

In my logbook I recorded that with my 17 mm Orion Highlight Plössl [71x, 43 min FOV, 3.6mm exit pupil], which gave me the best possible contrast of the nebula against the background, that I could detect "w/o Filt[er] several vF * around a fairly distinct center *", with a "Halo barely visible, 17 no filter", with UltraBlock filter "even better because F * also visible"; it was "Best seen OIII, 17mm". I made no comments regarding its being "difficult" or requiring "averted vision", which I will almost always do in such cases. In fact, my drawing of a 'closeup' view -- shown below -- obtained when I employed my 6 mm Expanse eyepiece [200x, 20 min FOV, 1.3 mm exit pupil] shows some of the stars around the nebula, and some "sparklies" detected inside it. I seem to have recorded seeing a "fairly distinct ctr *" but the POSS picture suggests that it's just the perception of an average of a close grouping of extremely faint ones. At next viewing, I'll be sure to use 400x to try to better see those faint interior stellar details.

Unfortunately, though: my chart table has to be located almost 20 feet away from my scope, so the drawings were done after I'd left the eyepiece and walked over to it; took a moment to sit down, pick up pencil; orient the paper; and then to try to remember what I'd just seen. So, the positions and angles in this rather complex closeup view of the highly magnified nebula don't seem QUITE to match precisely the image I obtained from the UK2 blue plate, cropped and rotated/inverted to agree as closely as possible with what I had sketched. (One must also make allowances for the differences in the eye's perception of star brightness, compared to the way they register on a blue sensitive photographic plate.) Nevertheless, I had drawn some "speckles" inside the halo of the planetary, recording (however inaccurately) my impression that more of it could be seen then just the faintest-possible "blob". However, you will note that my sketch does not suggest that I perceived the somewhat brighter, narrow 'edge' of the outside of the halo that shows up in the picture based on the red plate, used for the wide field illustration at the top of the article; this is not as well shown on the blue plate monochrome picture, immediately above.

Earlier, at 1:15am on 15 January 2007, and later at 1:50am, I had made notes about my previous sighting of Abell 23, saying that in a moderate power / wide field it was "near what looks like an = mag double star, maybe 9-10M". Looking at my star chart program, I confirmed that indeed an apparent optical double, consisting of a 9.48 star and a 10.54 m star, separated by 36", may be found some 12 arcminutes north of Abell 23: further confirmation that I had seen the object twice, in 3 days' time. I have highlighted those stars in faint blue haze, on the planetarium program's "screen dump" picture, above. I don't know what more I could do to try to 'prove' that I'd seen the object -- not once, but twice -- and found it not particularly difficult (not NEARLY as hard as Minkowski 1-18, for instance!); perhaps a "Vulcan mind meld" would be the only thing that would convince any remaining skeptics.

Looking on public Internet webpages, I could find no other reports of viewing Abell 23, nor even so much as ONE photograph or digital image. When I searched for Abell 23 with Google images, pictures of lovely Abell 39 showed up, not Abell 23. So, perhaps the image that anybody may prepare from the Digital Sky Survey data will be the only pictures currently obtainable, at least until some hardy amateur astrophotographer with good southern horizons and lots of patience (and a willingness, if located in N. America, to work in the dead of winter!) will try to create a good, high quality color picture.)

Now for a slight digression: about HOW I make these images. One of my correspondents wrote to me recently about some of the faint objects I've discussed, finding it impossible to corroborate the background nebulosity that I had shown in my picture, saying "I tried enhancing the Palomar picture's contrast but the nebula didn't show up. Maybe you're better at this than I am." Well, without trying to claim any special expertise, I would have to explain that I've been doing digital astro images since the middle 1980s, when I was helping to prepare an astronomical products catalogue with Macintosh computers and professional-quality processing software. Somewhat later I studied common image formats and writing graphic display functions with C, in order to add features to my own software programs. In my earliest days with PCs I used rudimentary DOS graphics editors, forcing me to become very familiar with techniques of manipulating palettes in order for the results to be cross-platform compatible. Maybe years of such drudgery help one to intuit if there is any latent information in a picture than can probably be SQUEEZED out of it.

Most of the time I use a piece of low-end graphic editing Windows software that came free with my $29 Canon scanner: it's called PhotoStudio 5, by Arcsoft. It contains the all-important tone shading and contrast enhancement features that can turn an almost 'totally black' POSS picture into something that has more than just a few faint stars. You see, the image data are THERE, but are shown with an "undistributed middle", most of the information being concentrated in just the brightest stars, or the nearly dark background. By increasing the middle tones, and then carefully balancing the contrast, the nearly invisible object data are placed within a range that may be registered on a typical computer display. It is important not to MANUFACTURE data by over-processing, which can be done if one uses, say, too much "unsharp masking", or stretching the contrast until very slight differences in gradation are turned into sharp boundaries. It is as much an art as a science, and I make no claims that MY reprocessing of the GIF data from the DSS pictures will be absolutely correct in its linearity and relative contrast. And, since the POSS scans show definitely that some plates were underexposed, or occasionally that the sky conditions were imperfect, one must also make adjustments to try to maintain some consistency, and occasionally to "sharpen" the picture, especially when a huge area of sky has to be reduced in dimension to the fit available web page space for the graphic.

After the faint nebulosity, galaxy arms or other latent details are brought into visibility -- which might require as many as a DOZEN iterations of each process in order to get the data into properly visible range -- it's necessary to apply numerous techniques to smooth or average any "jaggedy" boundaries that were created with heavy contrast- stretching, or to reduce a "lumpy" background noise or film grain pattern (taking care not to obscure faint nebulosity.) PhotoStudio has many such functions, most suitable for common daytime pictures though a few are valuable for astronomical images, including Gaussian blur, unsharp masking, scratch removal, threshold adjustments, and changing video resolution depth modes. Sometimes interesting enhancement effects can be created merely by re-sampling, resizing, and then smoothing: which might cause an enhancement of edge detail.

As the screen dump shots immediately above of the Tone and Brightness/Contrast adjustment panels show, the POSS/UK2 plate registration of Abell 23 as first downloaded looked almost blank, aside from a few of stars; but with successive steps of processing, the lovely shell of the nebula became quite well defined. Rarely do I need to use any other program to process the POSS data, but occasionally a friend assists by running the near-finished pictures through a step or two of alteration with Adobe Photoshop Elements, using the luminance level histogram adjuster, or the "color variations" function; or I even use an ancient Win 3.1 version of Photoshop LE that I got free, with another scanner that I purchased more than fifteen years ago. Once in a very great while, I also use the "anti-moire pattern" feature of another ancient graphics program, "Photofinish" by Z-Soft (an antique that I've kept alive for the sole purpose of cleaning up half-tone illustrations.)

It must be said, however, that Abell 23 was sufficiently well registered on the POSS/UK2 red plate that I was able, in just a very few minutes, to produce the picture at the top (a 10 minute square region), which indicates that it is by no means one of the faintest of the Abell planetaries. Indeed, I decided not to use this red plate -- which showed TOO MUCH of the nebulosity! -- but instead the blue plate, for the 'closeup' image that is used in the comparison with my drawing made at 200x. Since my experience with this nebula -- both in the viewing of it, and in the processing of the POSS data -- indicates that it is not the greatest of challenges, I wonder why so few amateurs seem interested in it? I hope this article will prompt some investigation. You may use the Deep Sky Browser page for the object in order to create a finder chart, if needed.

If you're keeping an "object count", then -- as long as you consider this to be two objects, per Herschel -- here's a 2-fer! Until fairly recently, perhaps, this has been a rather obscure item, not particularly known to amateur astronomers (I don't recall reading anything about it in Walter Scott Houston's columns, and found very few references in my oldest observing books and lists.) Though it was included in the 1989 book "Observing the Constellations" by Professor John Sanford, a reference that I was permitted to use for my "Eyepiece" software program, due to its faint magnitude rating I left it out, the database function having room only for 110 planetaries. Sanford has it listed on a table of objects but does not deign to comment about it. I can't positively remember looking at in in past years; possibly did so but formed no lasting impression.

However, when I was using my C-11 telescope at "the site" on Wednesday morning, 18 October 2006, and put my GOTO scope onto its field, I was absolutely bowled over by what I saw. My logbook records some of the excitement that I felt: "!! Splendid obj. With 7.5mm Lanthanum [373x, 8 min FOV, 0.8 mm exit pupil], no filter: PN looks almost like 2 colliding gx's. OK with filt, but not necessary. Central * vis. w/3.7mm [755x, 4 min FOV, 0.4 mm exit pupil]: somewhat easier than ctr * of M57."

Steve Gottlieb's very interesting and detailed observing notes, done with the aid of a 17.5" telescope, are archived here: search for the NGC number. As reported in 1993, using an 8" f/10 SCT, the PN enthusiast Yann Pothier comments that:

...at 145x, medium sized PN, medium brightness, elongated (estimated to be 73"x36") in a NE-SW axis, with two brighter lobes at the ends; the SW lobe is brighter and contains a mag13 stellar knot (that is not weakened by the OIII so it's not a star, rather a nebular condensation); OIII [gives] an overall good contrast gain and gives a clearer view, better separating the 2 lobes; no central star; the nebula forms a triangle with 2 mag10.5 stars 8' to the WNW and SSW; a double of mag13+14 (20" to the NE) is at 2.2'NW.

As you may observe from the picture I've prepared above, using the red plate of the POSS/UK2 survey, the object looks quite complex. William Herschel discovered it in 1785 with his 18 inch telescope, ascribing a number to each of the two distinct lobes that appear around a central star: the SW element being now ID'd as "NGC 2371" (lower right from central star) and the NE element termed "NGC 2372": the PK catalogue number correctly refers to it as consisting of one object, PK189+19.1, a "bipolar" planetary. I have tried to recover Herschel's original descriptions for what came to be known as "H II 316" and "H II 317" in order to determine exactly what his designation for the object(s) would have been (presumably either 'Class I - Bright Nebulae' or 'Class II - Faint Nebulae'); but all references to the original Herschel catalogues available on the Net currently seem to have substituted the NGC equivalent descriptions, most with the RNGC updates. At any rate, it is said that the object was NOT considered by Herschel to be a planetary nebula. It was first given that classification in the publication of the photographic analysis by Francis Gladheim Pease, an important Mt. Wilson astronomer and optical designer for the Carnegie Institution, in his 1917 paper, "Photographs of nebulae with the 60-inch reflector, 1911-1916".

The detailed professional paper by Dr. Walter A. Feibelman, published in 1997, reveals that its spectral content is mostly short wavelengths, including nebular lines of carbon, neon, oxygen, helium, and silicon. Modern catalogues rate it as having a diameter of 74 by 54 arcseconds; a visual magnitude of 11.2 (older references often claimed something on the order of "13.1"); and a surface brightness of 11.31 mag/sq. arcminute. The central star has a visual magnitude of 14.8.

It is interesting to note, from the picture above as well as from my own observing comments, that the central star under optimal conditions may be quite distinct: I saw it with my 11" scope, and Gottlieb did with his 17.5 incher. The central "engine" for M-57 has a visual magnitude rating of 15.0 (per the ESO catalogue) and has definitely been detected, occasionally, with the aid of telescopes of 8" of aperture and even once in a great while, slightly smaller: I've done it myself. But perhaps the very slight differences in brightness and color, plus the greater presence of nebulosity around M-57's central star, make the discernment by visual astronomers of NGC2371/72's central star a bit easier.

Here are some wonderful modern pictures of the object. One that somewhat resembles, though being a bit fuzzier, what one could see by eye with a moderate to large aperture scope, done by George Normandin, is on the Kopernik Observatory website. That article contains a link to a Hubble picture mosaic, done by principal investigator Dr. Howard Bond: showing that the central star is definitely yellowish, not blue (as in the case of M-57.) NOAO's Planetary Sampler page for the object has a monochrome picture that looks somewhat different from the POSS sources, and informs us that the object has been nicknamed "the Gemini Nebula" and "the Peanut" by amateur astronomers. A fabulous, detailed color CCD image done with a Pollux 0.8m aperture telescope by Philipp Keller and Christian Fuchs is probably the best ground-based observatory image I've located. Those of us who enjoy drawing deep sky objects may find a sketch by Bill Ferris on his website (a page that for some reason I wasn't able to bring up on the day I collected links for this article), and will be able to locate four observers' drawings, and reports, on the Finnish Deep Sky Archive, a website that required Javascript (and doesn't look quite right on my Firefox browser.) My friend Jaakko Saloranta has posted his 2001 drawing, based on a view with an 8" Dob, describing it as "Round nebula with two brighter modules visible in both sides. Southern module brighter. No central star." But, his top magnification was 196x. In reading all four reports I was reminded how well informed and careful those Finnish observers are, noting that the "stellar brightening" that may be detected at one spot in the object is NOT the same thing as the central star!

In the unlikely event that the object is not included in your star chart or planetarium program, then you may use this link to the appropriate Deep Sky Browser page in order to create finder charts. Be sure, also, to visit and enjoy the excellent Gemini Nebula page done by Greg Crinklaw, with a simulated eyepiece chart and wide area finder, and Greg's own color composite picture done from red and blue POSS plates.

Since July of 2005, when I purchased my new 10" and 11" telescopes and resumed observing after a hiatus of a few years, I have logged hundreds of galaxies at "my site": so many that it would be quite uninteresting, and very tedious, to report about them all in these articles (for instance: in an early night of testing my GOTO 11, I found forty galaxies, finally giving up after three hours when I felt overwhelmed.) Instead, I am focusing on the discussion of interesting phenomena, such as interacting galaxies; particularly faint and challenging ones; galaxies with anomalous and visible physical characteristics; and galaxy pairs that one may, with care, see in a single eyepiece view: such is the last characteristic that makes searching for these two objects a particularly worthwhile effort, in my opinion.

Our 'old friend' Albert Marth was responsible for sweeping up the "lenticular" galaxy that was added by Dreyer as no. 6944 in the New General Catalogue. It was found on 15 August 1863 with the gigantic 48" aperture metal-mirror telescope built by William Lassell, quite the machine! I remember how much this gadget fascinated me when I first read about it more than three decades ago in Henry King's 1955 book The History of the Telescope in the original facsimile Dover edition: a rather dry but very thorough recitation of facts, festooned with exquisite historic woodcut reproductions. Lassell's achievement was to perfect and make practical the huge reflector telescope with "speculum" metal alloy mirror, permitting equatorial tracking by means of a yoke mount (similar in concept -- but not in scale! -- to our familiar modern Schmidt-Cassegrain portable scopes.) And, unlike the enormous telescopes of William Herschel, Lassell's gigantic instrument was located in cloudless skies benefiting from favorable weather conditions: the island of Malta. So, this stupendous device permitted a significant break-through in the penetration of the depths of space. True, Herschel could have seen NGC-6944 with his 48-inch speculum. But, that monstrosity was so unwieldy that its inventor preferred to use its 18-inch predecessor. The brief wiki about Albert Marth informs us that, as Lassell's assistant, he was able to discover 600 new objects -- 'nebulae' as they were then called -- making him, I believe, third to John Herschel as the most significant contributor to the objects collected in the NGC.

Catalogued specs for these galaxies:

6944: 1.7' x 0.8' ; 13.3 v. magnitude; SB=13.4 (in magnitude per square arcminute).
    Dreyer: "pretty faint, small, round"
6944A: 1.2' x 0.9'; 14.9p magnitude; SB=14.7 (in magnitude per square arcminute).

In the Palomar-derived image I produced, above, NGC 6944 is shown above and slightly left of center, below the brightest star near the top (SAO 126045, magnitude 8.6); NGC 6944A is the fainter but still very distinct and somewhat more detailed galaxy near the bottom. On the Saguaro Astronomy Club website page for objects in Delphinus, Steve Coe reported these two observations, using his 13.1" f/5.6 scope:

NGC 6944 Very faint, small, elongated 2 X 1 in PA 165 at 150X.
NGC 6944A Extremely faint, small, only suspected at 150X, never held steady with direct vision.

The interesting sketch page for NGC 6944 by Bill Ferris states, amusingly, that "This faint little stinker swims with a celestial dolphin, Delphinus." Bill's drawing, done by means of his 10-inch aperture Starfinder telescope, shows more varied surface detail than the POSS1 blue plate that I used, at the top of this discussion, for a cropped (about 11 arcminute) field containing both galaxies, where NGC 6944 shows up as just a blob with a halo. Searching for other drawings, I found one by Giancarlo Forno, on the Italian language astronomy website of the Gruppo Astrofili William Herschel Torino. Unfortunately, the gargantuan menu of Forno's astoundingly huge number of drawings takes darned near FOREVER to load -- and then RE-load after you return from any one drawing. If you persist, you'll get Forno's image of the eyepiece view he had of the two galaxies, and his notes. I could barely make out his handwriting in order to try to translate his descriptions, but did intuit that he was saying that 6944 had a "circular form" with a "stellar nucleus", and 6944A was at "the limit of vision". So, despite the apparent "clarity" of the companion galaxy NGC 6944A in the Palomar picture that I prepared, it is the primary NGC 6944, discovered by Marth, that is actually much better seen by eye, as explained by Steve Coe. You may confirm the pictures of the galaxies from these two Deep Sky Browser pages: NGC-6944, and NGC-6944A.

Did I agree with this, when I looked at the two galaxies at "my site" on 24 September 2006, with my Celestron C-11? Yes, indeed. My logbook records observations that concur with Steve Coe (I had previously read neither his nor anybody else's description of the pair):

N6944 - fairly easy with Expanse 15mm [186x, 21 arcmin FOV, 1.5 mm exit pupil], 9 mm [311x, 12 min FOV, 0.9 mm exit pupil].
N6944A - VF! Barely vis w/9 mm.

The relative "eye brightness" factor of the two galaxies is suggested in this amateur CCD image I found on the net, done by S. Milicic and Natko Bajik, found on a page of images from the Visnjan Observatory near Split, Croatia. Unfortunately this relatively rudimentary CCD picture shows heavy pixel bleed and trailing, suggesting that the detector is an obsolete one, but it is actually quite useful as an indication of what to expect with (say) a 10" aperture telescope, by eye, in a dark and clear sky (ignoring the star image deformities); Jaakko Saloranta suggests on this webpage that the minimum aperture for viewing at least 6944 might be 8 inches. According to measurements I did with a star chart program, the centers of the two galaxies are approximately 6' 27" apart, suggesting that if you get one in the eyepiece -- most likely the visually brighter and more obvious 6944 -- you will probably be able to see the other one in the same field, if conditions of sky, aperture, magnification, and observing skill allow. What do YOU see?

0.5 degree finder: upright, correct

I anticipated a long  winter night/morning observing session starting at twilight on Thursday, 11 January 2007 at "the site", intending to work hard with my 10" Dob until the moon rose at 2:21am on Friday morning. But though the weather seemed cooperative at the beginning -- my notebook states "cold, clear & nice steady sky" -- it became apparent, after an extended and very satisfying look at planetary nebula Abell 7, pondering the possible existence of some faint background nebulosity (described above), that by 10:50pm there was reason to worry.

I noted, "cloud from SJ forming over top of mountain," an ominous event that I have often experienced at this mountaintop, at 3,400 feet elevation above sea level. I kept darting my glance between the telescope's eyepiece and the northern horizon, shaking my head and knowing EXACTLY what was likely to come. And, by 11:30pm I wrote, "Dodging clouds now." For this odd weather pattern -- a winter phenomenon -- was forming an unstable, wavery, and wet cloud bank at the heights, the opposite of autumn's experience of clouds and fog at the depths, far below me. What's worse than being 'all dressed up' but 'nowhere to go', submerged in frigid haze, moisture seeping into the cracks of your telescope and into your bones, while all the rest of the teeming multitudes of the south bay are pleasantly cozy under their nice, clear (light polluted) sky? Over the years this has occurred to me several times, a truly eerie experience.

As the cloud settles over, all sound is cut off (though it had seemed perfectly still and quiet at this location, the sudden and utterly amazing absence of noise of any sort is unnerving.) The normal sky glow of stars and faint light is swallowed up, as if a switch has been snapped: you can barely see the hand in front of your face. The air is simply WET. You sit, waiting and hoping for a wind to come up, or a temperature inversion: just for SOMETHING to make the darned thing go away. And you get colder... and colder. Finally, you lose all hope, and start to pack up your star charts (now soggy and limp), and sluice off the water from the telescope tube (having of course had the presence of mind to remove the eyepiece and throw your heavy coat over its front opening and the focuser and finders.) Gentlemen: the session is finished.

Sadly, my monitoring of the diminishing light dome from San Jose had suggested that this might be a rare, fabulous dark sky night -- but I hadn't wanted it to be quite this dark! Naked eye stars fainter than 6th magnitude were starting to pop out all over the constellations near the meridian. Before the cloud overtook "my site", I had searched the Orion region for the Witch's Head nebula, and saw the slightest trace of it. My "marker" star that indicated good conditions for the Horsehead had finally winked into view. But I decided not to succumb to that temptation and instead sought unfamiliar objects in the constellation. On my Sky Atlas 2000.0 I found three little green squares, Wil Tirion's tiniest isophote marks for nebulae, with ID numbers I did not recognize: NGC 2182, -3, and -5. So, these 'little' objects were the ones I was intent on studying when nature turned against me. I was rushing to achieve some kind of sighting of them before the cloud moved in, and did not even take the time to look them up in the Companion to the atlas, describing all the plotted objects. Often, I like to try to see something first, innocent of any bias, and then determine later if I was genuinely perceiving a detail without expecting to find it.

So I had no idea of the real size and shape of the nebulae, other than that they were something no doubt a bit smaller than indicated by the standard green boxes. Nor did I know of the constituency: emission or reflection nebulosity. I would test them as though I was 'discovering' them. I began to work with low power, as the chart showed that the three NGC objects might be separated by about a half-degree (actually, it's 24m 51s.) Using the absolutely widest field I could achieve with the instrument -- even at the expense of an inefficient and overly large exit pupil -- I looked with a 42 mm 2" barrel eyepiece [28.4x, 144 arcmin. FOV, absurd 8.9 mm exit pupil] and found myself 'dodging' the dark blob of the telescope's central obstruction; but the entire field was perceptibly aglow, with too many stellar points to count. Where, though, was the nebulosity most strongly concentrated? In a 2" barrel size I only had an UltraBlock filter, which is suited to emission nebulae that radiate ionized hydrogen and oxygen wavelengths near the color green, to which the dark-adapted eye is sensitive. I put it in, and was struck by the improved definition and concentration of the radiation: with a much dimmer field, one could tell where the 'pockets' of light were concentrated around brilliant points. But then, as I took a final look before starting to step over to the eyepiece case to change the ocular, the horrible cloud finally swept over me. I had experienced one short but good look, with one magnification: with and without a filter, allowing enough time only to scribble in my logbook those details and that the view was "very nice". And that, to this day, has been my only opportunity. What did I really see?

From east to west, as in the POSS1 blue plate above (covering about 45 arcminutes, and with scratches and defects removed in my graphical editor program):

Cederblad 71: Br refl neb; 3' x 2'; no given magnitude; more info.
NGC 2185: Br refl neb; 5' x 3'; 12.9b mag; * 11 and 4 S st in vF,L,neb; Herschel IV-20; more info.
NGC 2183: Br refl neb; 1.6' x 1'; 12 mag; eF,S,lE,* 11.12 sp; more info.
NGC 2182: Br refl neb; 5' x 3'; 12 mag; pB **,L * neb,E 90° +/-; more info.

NGC-2185 was discovered by William Herschel with his 18.7" reflector in 1784; 2184 by Heinrich Louis d'Arrest using an 11" refractor in 1864; 2182 again found first by Herschel in 1786. The Cederblad nebula, which was not plotted on the Sky Atlas 2000.0, is a small fuzzy patch of reflected starlight, rated in the original Lynds catalogue as being detectable mostly on the blue Palomar plate, and with a brightness of "3" on a scale from 1 (faintest) to 6 (brightest.)

Of course, I used the "wrong" filter. Given enough time, I would have changed to my 1.25" oculars and tried the SkyGlow (Orion's trademark name for the light pollution rejection type, useful for reflection nebulae.) And with more magnification at a smaller exit pupil, I might surely have prised out some detail and increased the contrast. Would the apparent dark lanes -- which started to show up as I used my software program to increase the contrast enhancement of the POSS1 blue plate -- have been visible in the eyepiece? Probably not, at least until my sky could show naked eye stars as faint as 6.5.

To determine if the "incorrect" filter had been totally futile, I also obtained the Palomar red plate, and subjected it to even more of my customary torture than usual. Surprise! For when there is reddish nebulosity (H-alpha) mostly from atomic hydrogen -- possibly remaining visible if only the shortest blue and ultraviolet wavelengths of reflected starlight had been absorbed or scattered by the dust of the galactic plane -- there may also secondary, fainter greenish radiation (H-beta) that will be seen with enhanced clarity using an UltraBlock filter. This phenomenon could explain why I did find that the "wrong" filter helped. I located another observer's report, by Richard Ozer, that seems to corroborate this:

Date: Sat Feb 08 2003

I went to Del Valle [county park in N. Calif., near Livermore] last weekend to finish logging Hershels in Monoceros. I chose Sunday night to do this because star hopping to faint open clusters in Monoceros makes regular Monday morning work seem easy in comparison.

I'd like to hear if anyone has notes on NGC 2185, the last item on my list for that night. I found it to be a very small fuzzy patch of light, observable with averted vision, and with the aid of an ultrablock filter... I'm wondering what other observers have thought about this one.

I'll be glad to oblige, Richard: I too think the UltraBlock helps, but I haven't yet tested the "correct" filter for a comparison.

Color images of the objects illustrate the likelihood that perhaps all of one's visual nebular filters could be of some assistance, notably this NGC 2182 wide field image, done by Adam Block with a 76 mm Televue scope, showing red radiation (invisible to the human eye through an amateur telescope, but signifying the presence of some fainter, possibly visible H-beta stuff); and a splendid NGC 2183 & 2185, by Neil Jacobstein and Adam Block, employing the Kitt Peak 20" RCOS telescope at f/5.5. I would not be surprised to find that the OIII and H-BETA filter will assist in seeing certain details of this region, and I shall certainly test them when possible, at a future sighting of this interesting field.

The highly- experienced Steve Gottlieb, writing in the ASTRONOMY magazine forum (registration required) has described an early 2007 viewing of these objects:

NGC 2170-2185 Reflection Nebulae: Just west of 4th magnitude Gamma Monocerotis is an interesting group of reflection nebulae mostly surrounding 10th magnitude stars. No filters are necessary as the glow is mostly reflected light off dust particles. From west to east here are my descriptions;

NGC 2182: bright reflection nebula, round, ~2' diameter, surrounding 9.3 HD 42261. In a group of reflection nebula with N2170 28' WSW and N2183 20' ENE.

NGC 2183: fairly faint , appears ~1' diameter and notably was *not* surrounding a bright star as are the other nebulae in the group. There appears to be a faint star, though, at the south edge which may be the illuminating star. A much larger complex of of nebulosity including N2185 is less than 5' E and SE.

NGC 2185: faint, fairly small, 1' reflection nebula surrounding a mag 12-12.5 star. This glow is a few arcminutes NE of a group of 4 mag 12 stars which are also encased in a larger 3' haze of weak nebulosity. Both of these pieces are part of N2185. Located 5' E of N2183.

In the collection of observations acquired by the Saguaro Astronomy Club, Steve Coe (using his 13" f/5.6 Newtonian) notes that:

NGC 2182 is just a fuzzy star at 100X. The UHC filter does not help.
NGC 2183 and 2185 are in the same field near Beta Mon. Even at a very dark site on a night I rated 7/10 for seeing and transparency there is not much here. At 100X in the 13" there are several fuzzy stars in a field that is noticeably void of stars compared to the nearby Milky Way. 2185 has star in the center of pretty faint and round nebula, 2183 is dimmer and has no star. The UHC filter does not help.

Finally, the editor of THE DARK-SKY OBSERVER newsletter of the Eastern Missouri Dark Sky Observers comments about this grouping (his abbreviation "DN" referring here, obviously, to diffuse nebulae, not dark ones):

NGC 2185 - DN: - 06h08.7' / 06d12' - Group of small, faint Diffuse Nebulae, located about 10 degrees NW of Sirius, & just about a degree and a half West of GAMMA MON, in the southwest portion of the constellation. Brightest of these, is 2185, which is on the first HERSCHEL OBJECTS observing list. 2185 is still, very faint w/ a mag. 12 star involved. Size is about 2'x2'. A CHALLENGE for a large scope. Probably Reflection nebulae, illuminated by Gamma, or some other nearby stars.

NGC 2182 - DN - 06h07.1' / 06d19' - mag 9 star embedded in faint nebulosity; dia 3'

NGC 2183 - DN - Part of NGC 2170, 2182, 2185 Group.

So, observers in darker skies than mine -- and with larger telescopes -- find that nebular filters are either 'not necessary', or that specifically the UHC (and, by implication, the similar UltraBlock) 'does not help'. Yet, we should not be deterred from trying them!

0.5 degree finder: upright, correct

Update, 1/29/09: My next visit to these 'little' objects occurred 24 months later, at the same site and with the same 10" instrument. I had been carefully documenting my perceptions of the large reflection nebula IC-447 (about 2 degrees east of the "Christmas Tree" cluster) and after spending nearly two hours on that fascinating region, I moved my scope nearly 18 degrees to the SSW, to catch these faint nebulae before they descended into the heavier air near the horizon. I'm sorry to say that I had forgotten about the "filter issue" discussed above, so I still have not tried to compare the SkyGlow to the UltraBlock on these reflection nebulae. Here are the observations of some of the fairly easily discernible objects across an angular distance of about 5 degrees, ranging from the western edge of the constellation Orion into Monoceros:

NGC-2110, lenticular galaxy ENE of 55 Orionis. 12:30A. With 7.5 mm [160x] can see it but not with 9 mm [133x]. Gx is oval, about 3:1, very faint, low surface brightness, oriented about N/S, maybe as much as an arcminute in diameter (actually, rated at 0.7x0.5.) Ext faint, v slightly brighter nucleus, AV helps.

NGC-2170 (refl neb) is a pretty distinctive glow in the 12.5 mm with SG filter, around 2 stars that are perhaps 11th and 12th mag and oriented N/S. With AV I see that the glow extends out to the E and W, with another bg glow at least 2 to 3 times the distance between those stars, particularly to the SE (could this be LBN 999?)

VdB 68 (refl neb) is an asymmetrical glow around a star of 9th to 10th mag, glow extending mostly to the SE. There are two other similar brightness stars in this nebula.

VdB 69 (refl neb) is a somewhat larger, but fainter, glow around a single star of similar brightness (perhaps 10th mag my estimate; Hipparcos 29082 is actually V=9.65 mag.)

NGC-2182 (refl neb) is a hazy patch around a single star, a little extended E-W; there is a much fainter star to the E of the glow, which encompasses that star.

NGC-2183 and NGC-2185 seem to be a continous and much fainter glow that extends E-W around a grouping of v faint stars, maybe about 13th mag, in a broad triangle, with a little bit of glow extending around them: very amorphous and hard to trace out, with 9 mm and SG filter. Objects are very low at 1:12 am.

The negative DSS image of N2185 and 2183 shows that the brighter centers are not, as appeared to my eye at 133x, 'continuous' but are well separated; however, there is a perceptible faint "background continuum" that is brighter than the general starry field.

Perfect conditions! At midnight, on Tuesday 20 February 2007, I had been observing for about three hours at "the site", marveling in the wonderfully steady and transparent sky: so good that, in fact, I had used the Horsehead nebula as a test subject, and found that even when it was only about 10 degrees above my western horizon, itself obscured by trees for about 10 degrees, I could see it with my 10 inch Dob -- just barely -- using a 6.8 mm exit pupil and UltraBlock filter with my new Orion Q-70 2" eyepiece, the lowest elevation of the object that had ever allowed me to see even a trace of it. Bright stars had perfect Airy disks with unbroken first diffraction rings. The wind was calm; the temperature moderate; the humidity low. The experience was almost summery, and -- best of all things -- a heavy layer of ground fog had formed below me, obscuring much of the skyglow from the lights of Gilroy and Morgan Hill. The only drawback: I was dead tired from straining, earlier, to see a very faint galaxy pair for an entire hour. After a break, some refreshment and coffee, I resumed, looking south and seeing a remarkably black, clear celestial background: now a truly "dark sky site", and yet only about a dozen miles (as the crow flies) from my house in San Jose.

Looking upward at the small but immediately recognizable constellation Corvus, whose trapezoidal star pattern stands out in a field of relatively few bright points, I snatched a quick view at an old favorite, the "Antennae" galaxy pair (NGC-4038, 4039), an incomprehensibly cataclysmic cosmic collision that affords an excellent sight in even a much smaller telescope. These objects are not challenges and can be seen with much heavier light pollution than I was now experiencing. What else could I find that would pose more of a challenge?

The planetary nebula NGC-4361 stood out as the only such object of its type in the constellation of Corvus, and certainly the most interesting deep sky object for a visual observer, amongst the plethora of extremely faint, obscure galaxies inside the asterism of four stars that marks the central region of the constellation. It is plotted on the "DeepMap 600" and many beginner-level sky charts, and is so bright that one wonders why Messier or Mechain did not make note of it. But, like many other planetaries it has fascinating visual details that are challenging to observers, demanding clear air, good optics, and excellent discernment. William Herschel discovered it with his 18.7 inch telescope in 1785, but it certainly does not require that much aperture to perceive: Yann Pothier reports here his observation with a 4.25" inch telescope, finding that this 11th-magnitude object was, at low power, a "very small nebulous patch, quite faint with brighter center." Yann could see the 13.0 magnitude central star erratically as it winked in and out in his small telescope, at the threshold of perception. I found that in my 10" scope, that central star was exceptionally clear, crisp, and relatively bright: steady with direct vision. Most visual observers have commented that the nebula has two shells: a bright inner one, and a dim outer one (with a diameter that is oval, measured 'officially' as being 93 by 37 arcseconds.) As I looked at it, I wondered when had been the last time I'd seen the planetary. Checking with the list of PN's in my "Eyepiece" program, which used the objects chosen for each constellation by John Sanford, I see that it is included, which means I had definitely studied it back in the late 1980s/early 90s at this same spot, probably with a variety of scopes that I then owned (from 8 inches to 17.5 inches of aperture.) But I could not remember anything I had experienced before, and was forming fresh impressions.

My logbook records that I was deeply impressed, awarding it " ! ! ! ", my remark for wonderful objects that stand out dramatically. I also scribbled, "Wow! VL halo, ctr * vis with 9mm Expanse [ 133x, 29 arcminute FOV, 1.9 mm exit pupil], not requiring any filter. With 6mm [again, Expanse: 200x, 20 arcmin FOV, 1.3 mm exit pupil] the bright neb'y seems mottled. Using 3.7 mm [Orion Epic, 323x, 10 min FOV, 0.8 mm exit pupil] the effect is either equal brightness faint stars, or neb'y variations, across halo." I then used lower power that would work properly with nebular filters: "with 15 mm [Expanse, 80x, 49 min FOV, 3.2 mm exit pupil] the disk is better seen with OIII filter than UltraBlock."

I had no thorough collection of resources with me other than the Sky Atlas 2000 and its Companion by Strong and Sinnott, and no pictures. And I had not prepared to look for the object, and thus did not form my opinions based on looking for specific details that I'd read about. It seemed to me that the nebulous 'disk' of the planetary smoothly varied -- though there were distinct regional variations -- from the central star to the outer periphery, where it faded without a sharp edge to the sky background, even at highest power. I saw no "inner and outer" shells. But, the nebulosity was indeed brighter near the center.

My final test was to try an eyepiece-Barlow combination that yielded a bit sharper image than the rather "soft" Epic ocular view: a 10mm Plössl with 2x "Shorty" Barlow [240x, 12 minute FOV, and 1 mm exit pupil]. I recorded seeing something vague and unexpected: "Is there any chance of an outer halo?" I can only do a very rough estimate, knowing the FOV of my various oculars, but with my 3.7 Epic, the wider diameter of the planetary did seem to be about an arcminute (a tenth of the entire field width.) It was slightly smaller looking at the lower power -- 240x -- of the Plössl/Barlow combination. But, after very long and careful scrutiny, I thought I could also see something else, further extended out from the planetary's distinct and bright disk. I seemed to perceive a sort of broken outer ring of FAINTEST nebulosity, with maybe six times the diameter of the planetary's disk. I sketched it, as shown below.

My drawing, done at the eyepiece of a Newtonian telescope, showed a reversed, inverted image. The halo was therefore most distinct in the orientation shown, which would be upside down and backwards compared to a pole-up picture. I got out the Companion and looked up information about the planetary, finding that the authors had written "large, round disk involved in a larger, fainter disk" and wondered if this is what I'd seen (since the actual bright fluffy glow of the planetary seemed to be, itself, a continuous though outwardly dimming shell of gas.) A few hours later I was at home, still in the wee hours of the morning; but I was too fascinated by the object to go to bed immediately. I fired up the nearest PC and went on the Net for further information, finding a number of excellent observing reports such this web page by Crinklaw, which inferred that my perception of a smoothly fading brightness, not two discretely luminous layers, was different from the experience discerned by others. Surely my "faint broken halo" just at the threshold of perception was NOT what these commentators were referring to as the less-bright outer shell, which was defined by the size of the plotted diameter, not six times wider.

Later, after some sleep, I resumed the research. I downloaded several good modern pictures, and decided that the definitive one was this fabulous color CCD image by Elliot Gellman, Duke Creighton, and Adam Block using the Kitt Peak 16 inch "visitor's" Ritchey telescope. In the full spectrum of color, the 'two shells' are clearly shown, the inner one radiating a mixture of wavelengths -- probably oxygen and hydrogen -- that one perceives as pink; the outer one dimly green (probably largely doubly ionized oxygen.) To my telescopic eye, there had been no "boundary" but only a smoothly diminishing brightness outward from the central star. BUT... earlier in the evening I had looked at R Leporis, the fabulous red star in Lepus, to test my own ability to see faint red light. I had found that while other observers report a ruddy hue that is distinct, even 'like a drop of blood on the sky', to me the red color was only barely apparent with my "good" right observing eye, and perhaps only a bit stronger with my astigmatic, "bad" left eye. Once again, I had confirmed that my own physiology, age, and possibly other unknown other factors had combined to make me distinctly less sensitive to faint red light than other deep sky observers report themselves to be.

Thank goodness, though: I'm still very sensitive to faint light perceived by the colorless "scotopic" vision, via the rods of the retina, of the dark-adapted eye. So, I was definitely SEEMING to see something further out than the 'dimmer shell' that showed so clearly in the color photo.

The Deep Sky Survey pictures via the Australian-UK Schmidt telescope had captured good images of the planetary, but the blue plate was badly "burned in", with a bright featureless blob in the center. So, I downloaded the red plate and did a superimposition composite, for the picture of the nebula shown at the top of this article. Thus, I was able to illustrate both the green-blue outer halo, and the reddish inner region, as well as the bright central star. This composite is stilll not quite close to what I saw by eye, since -- to me -- the puffy outer region blended smoothly into the bright core.

Could there then be something else, further out, related to the planetary? Nothing showed up in the first glimpse of the UK or the Palomar Schmidt plates, but heavy processing of the Australian blue plate started to bring something up out of the background; it was lost in the grain of the older Palomar plate. To have more than one corroborating source, I obtained also the HST GSC1 and 2 images. When I examined the results, the Palomar blue plate failed to show it at all; and the UK Schmidt blue plate, and HST GSC1 image, seem to be the same identical source data. The HST GSC2 plate, however, is different, and it DOES NOT show the background glow, as you can see from the comparison here (though there seems to be a trace of a variation in background illumination.)

If the glow is real -- corroborated by the UK blue plate -- then perhaps I did see it. If it is not real, judged from the heavily processed HST GSC2 (and Palomar blue) plate, then I experienced an illusion.

The question becomes this: can a dark-adapted eye, working in a very dark sky, see a region of faint, large diameter glow that is hard to photograph? I refer you to my article on Baxendell's "unphotographable" nebula, considered now to be one of the spurious objects in the NGC, for a related discussion. I must keep an open mind about the alleged phenomenon. It is certainly possible that there is a trace of galactic nebulosity or glowing dust in the region, and that under the exact conditions of my own eye, my instrument, and my nice transparent sky, I was able to spot it; under other circumstances, it was either "photographed" or "not photographed" as the Deep Sky Survey pictures suggest. And, I was not using a filter at all when I saw it: so claiming "filter illusion" is not appropriate.

If you would like to check this out, you may make a finder chart for the region with this link to the Deep Sky Browser page for NGC-4361.

• Link to Jaakko Saloranta's observation by means of an 8" Dobsonian scope.