There are informative Wikipedia pages on these two interacting galaxies of the pair Arp 94 that alleviate the need to repeat much of the data here: see these links for NGC-3226 and NGC-3227. William Herschel discovered the objects in 1784: yes, again with his 18 inch speculum metal mirror reflector. The NGC description is "pretty bright, extremely large, round double nebula" with position angles given. The visual magnitude of the wider spiral galaxy 3227 (5.6' x 4') is a bright 10.8, with a surface brightness of 13.9/square arcminute. The smaller 3226 (2.8' x 2.5') is rated at magnitude 11.4, with surface brightness of 13.3. I did not have any conception at all of these two objects while observing on Tuesday morning on 20 February 2007 at "my site", casting my scope upon "The Realm of the Galaxies" as it had risen to the meridian. I had never looked at the Arp pair 94, plotted on my Sky Atlas 2000 as two small overlapping ovals, one slightly larger than the other. What exactly would they look like in the eyepiece of my 10" Dob?

The air was crystal clear on that day, with seeing that I described in my logbook as being "superb". Rather heavy (rare) winter fog had formed over distant Morgan Hill and Gilroy, which ordinarily cast a nasty orange shine halfway to the zenith in the eastern direction. But, there was now only a dim glow below a very sharp atmospheric demarcation; above that, the sky was very dark. The stars at the zenith were crisply etched and steady, nearly as dark as the local sky becomes except on the rarest of autumn nights. This was an excellent time to look for the details of faint galaxies: and in a few moments I'd swung the scope around from the starting point, the bright star Algeiba, 50 arcminutes to the west of the galaxy pair. In my 15mm Expanse ocular [80x, ~49 minute FOV, 3.2 mm exit pupil] the two galaxies were an impressive sight, a nice smeared smudge of light. Increasing the magnification, I went up in two steps to the highest power reasonable under the sky conditions, switching from my 6mm Expanse all the way up to my 3.7 mm Epic eyepiece [323x, 10 min FOV, 0.8 mm exit pupil]. In that field, about the same width as the POSS1 blue plate I've cropped and processed for the image above, I saw a fine distinction of the two nuclei. I could also see a halo of light around each galaxy...and something else!

There was, in fact, a continuum of faint glow between the two. I nudged the telescope a bit, and watched the star drift, to determine my directions, and then made a sketch in my notebook. I reproduce this here, with a very slight "airbrush" smoothing of the pencil lines that indicated on the original my impression of the soft halo, and with superimposed color labels for the direction, as seen in my scope's inverting, reversed optical view. I wrote, as you can see, "Two br nuclei, 'neby' extending offset on W, between - 3.7" [mm eyepiece]. I opened my my Sky Atlas Companion by Sinnott & Strong, and found this description: "A large, very faint loop extends from nearby Seyfert galaxy NGC 3227 to this object [3226]", and that loop (a faint outer arm of the larger galaxy) was clearly visible to me. Examining the original sketch closely, I can see that I drew the nucleus of NGC 3226 with stronger strokes of the pencil: though this galaxy is the smaller diameter of the pair, its nucleus seems distinctly brighter to the eye. I was lucky that the sky had become so dark, quite unusual for February at my locale. That, and the steady seeing, made the faint detail of the dim outer arm -- which probably shows up even better in the negative processing of the picture on the NGC/IC Project website -- as clear as could be!

Here are Steve Gottlieb's descriptions, using his 17.5" scope:

NGC 3226: 17.5": moderately bright and large, slightly elongated SSW-NNE, smoothly increases from halo to a bright core and an almost stellar nucleus. The halo extends to almost 2' diameter with averted vision and fades into background. Forms a striking pair with N3227 at the S side with 2.3' separation between centers. The outer halo is just in contact with N3227 at the SSE edge. N3222 lies 13' W.

NGC 3227. 17.5": fairly bright, elongated 5:2 NW-SE, 2.5'x1.0', prominent very small high surface brightness core, striking stellar nucleus. Just in contact with N3226 at the NW tip 2.3' separation between cores. Brightest of three with N3222 13' W.
13": fairly bright, elongated, bright core, stellar nucleus. Forms a contact system with N3226 2' NNW.

It might well be, judging from this report by Peter Chapin, that the pair could be detected, at least erratically, by a careful observer as a "double galaxy" in a telescope as small as 75 mm of aperture; although my friend Jaakko Saloranta has looked at them with his 8" scope, shown on his webpage of objects in Leo, he hasn't yet tried with his 80 mm (but thinks that it might be possible.)

I tried twice over a period of hours to bring up the webpage of Bill Ferris that has his drawing of the galaxies, but his server did not respond: here's the link, in case it works intermittently. Vincent Le Guern has produced a drawing, based on a view at an amazingly high magnification of 650x, that is remarkably different from my depiction. In his image, the elliptical galaxy has a "pinpoint" nucleus, which would appear not to be as bright as parts of the Seyfert galaxy, the opposite brightness relationship that I saw. He also fails to register the extended arm, or "loop", that supposedly connects the galaxies; yet he sees very distinct bright spots on the northern edge of 3227. I really did not see those, at 323x. At first, I was baffled by the numbers scribbled below the drawing, which I perceived as: "T 760, 600m [or possibly mm], 650x": does he indicate an aperture size and focal length (unlikely, if you take the numbers literally!); or is the "m or mm" actually an "x"? Or, was he mentioning a telescope model number and focal length? So I did a search for his name (isn't Google wonderful?!) and came up with a web page in French about his construction of a 760 mm (76 cm) aperture Dobsonian. Here's a picture of this remarkable scope. The optical parameters are: "Diamètre=760mm - Focale=3122mm - F/D=4.1", which means that he was using a telescope with 29.9 inch aperture and focal ratio of f/4.1, which yields 8.95 times the light gathering of my 10" Dob. Yet, he failed to record seeing the connecting bridge that I saw, and that Gottlieb detected with his 17" scope, and that Bob Hill spotted with his 12.5"...go figure. (My guess is that in a 76 cm aperture scope, the bright central regions of the two objects are so brilliant that they "swamp" the fainter light of the outer halo/arm: similar to the problem of trying to see the Horsehead nebula in a wide field that also includes bright "competing" stars.)

Here is a fine splendid color CCD image by Glen Youngman, taken with his marvelous Takahashi 128 mm astrographic refractor in a dark sky site in Penryn, California; and an even more detailed image done by Sid Leach, Wil Milan, and Adam Block with a 20" Ritchey at Kitt Peak. I'm adding NGC 3226/7 to my itinerary list, but I don't think I've quite accumulated enough bonus miles yet.

NGC-1888 was discovered by William Her...oh, the heck with it; you can guess! But NGC-1889 wasn't discerned until 66 years later, by William Parsons (the Third Earl of Rosse, owner of the largest telescope then operating in the world, the 72" reflector.) When the object was added to the NGC, it was given this description: "Makes a close D neb with h 352" (NGC-1888), indicating that the separation of nuclei was noted by Parsons. Strange that Herschel hadn't seen that himself.

This pair of galaxies was included by Dr. Halton C. Arp in his "ATLAS OF PECULIAR GALAXIES", though the specific pair -- included in the Elliptical Group (102-145) -- was not claimed by Arp to be interacting, probably merely overlapped optically. According to my reading of the original paper (scarcely the analysis of an expert!), Arp cites three separate, distinct sets of redshift measurements, a pair referenced to Humason, Mayall, and Sandage (1956), who gave two values, finding them to be separated significantly; and one to de Vaucouleurs (1964), who didn't, deriving an interim redshift value. Using the latest redshift values obtained from the NED website, the distance calculations -- via this particular javascript applet -- work out to 34.25 Mpc for NGC-1888, and 34.96 Mpc for NGC-1889.

On his Arp Peculiar Galaxies website, Dick Miller quotes the Arp atlas as specifying a "Faint parallel feature on opposite side from S0 galaxy" (the only specific comment on Arp 123 in the original ApJ paper, which you may download here.) Miller comments: "That is just visible as a thin dark absorption line running along the southwest side of the nucleus." Unfortunately, an entire morning and early afternoon of searching the Net that I undertook for this article yielded NO amateur photos of the pair, so these details must be judged only from the DSS pictures. The original POSS plates are heavily burned in, so that the two galaxies seem completely merged, as shown on here in this scan of the blue plate. Since every other image I turned up seemed to be derived from one of the optical wavelength DSS pictures, and all suffered significantly from this overexposure, I resorted to the POSS2-UK infrared picture, which I cropped to an angular diameter of about 12 arcminutes for the large image of both galaxies at the top of this article. Here, the nuclei are separated and the halos do not merge into a bright continuous blob.

In order to determine the appearance to the eye of the true separation of the galaxy cores, based on some data extracted from the photo, I took the image and reduced the data set so that the luminance levels were greatly diminished, creating an artificial appearance but tracing out the general isophote contours. This picture -- left, oriented the same way as my sketch below -- shows the distinct separation of the nuclei.

Because the bright broadband light of the galaxies did not overexpose the red-sensitive plate, the infrared picture used at the top of this article is indeed closer to what I eventually perceived, by eye, after more than two hours of work on the pair, split over sessions I had at "my site" on Friday 16 February, and the following Monday 19 February, 2007, using my 10" Dob. In the course of this work, I made no fewer than four individual drawings of the galaxy positions. At first, I struggled mightily to see much of NGC-1889 at all. I wrote in my logbook, "N1888 - Smoothly extended, slightly bright nuc, speckled or F*s?" This referred to a sense that I could see some detail at one edge of 1888's core, using my 9mm and 6mm Expanse oculars [9: 133x, 29 min FOV, 1.9 mm exit pupil; 6: 200x, 19 min FOV, 1.3 mm exit pupil].

My first drawing was partially correct, but I seemed to perceive the elongation of NGC-1888 to run 90° to its actual orientation: only the nuclear region was distinct, the rest being extremely faint, and hard to see clearly, averted vision being necessary. I was somewhat dissatisfied with this observation, and repeated it on the very next opportunity, at the start of the next week. On Monday, I studied the objects for 45 minutes, making three completely separate drawings, one of which had "alternative" positions for NGC-1889, about thirty arcseconds apart: I still wasn't absolutely certain. On the second drawing I thought I got closer to my eyepiece impressions; after more scrutiny, by the time I made the third drawing, I was surer yet. However, when I got home and compared them to pictures, it turned out that the FIRST drawing of that night was VERY close (which I noted on the logbook before scanning the page.) I am so pleased with it that I've taken the POSS IR picture and rotated it to agree with the orientation shown in my sketch, based on a view with my 7.5 mm Lanthanum eyepiece [160x, 18 min FOV, 1.6 mm exit pupil]. Matches pretty well!

By the time I'd spent another thirty minutes suffering with this barely perceived smudge of NGC-1889, I was apparently "overdoing it" and not perceiving its position and dimension as accurately as I had when my eyes were more relaxed. Yet, my fourth drawing (not shown), with inaccurate position angles of the galaxies, nevertheless recorded QUITE properly a little trapezoidal pattern of faint stars to the SW of NGC-1888, agreeing with the POSS picture in that regard. (Please note that I did not have a picture with me, for either observing session. Indeed, on the previous Friday, I had never seen any image at all; and by Monday night, two days had elapsed since my quick check of web references about the galaxy on Saturday morning. So, my eyepiece impressions are reasonably unbiased, and are mostly derived from my growing accuracy of perception, the second session yielding significantly more detail on 1888 and better positions of 1889 the longer I studied the object, using different magnifications -- but only up to a point of diminishing returns.)

Today while preparing this report, I looked for other amateur observations, and found a few done with much larger telescopes than mine. On this webpage, Andrew Murrell used a 20" f/5 Dobsonian at Ilford in the UK, and noted:

NGC 1888/9
An interesting pair of interacting galaxies.
NGC 1888 is an edge on galaxy with a large nuclear bulge. The core of the nucleus is quite bright. The outer arms extend to about 3' with averted vision. The NE edge of the galaxy has a sharp edge. NGC 1889 is a compact galaxy, 20" diameter, just north of the nucleus of NGC 1888. The nucleus of NGC 1889 appears to reside in the outer halo of NGC 1888. There were no stars associated with the galaxies.

Yet, in contradiction regarding Andrew's finding of "no stars associated", Steve Coe's notes for Lepus, published on the Saguaro Astronomy Club website, gives these descriptions as seen in his 13" f/5.6 telescope:

NGC 1888 Pretty bright, pretty small, elongated, brighter in the middle at 135X. A pretty faint star is involved on the west side.

As if to illustrate that sometimes aperture isn't everything to amateur visual astronomy, Paul Alsing, in his article about a night of observing with a giant professional observatory scope, writes:

I had the opportunity the new-moon weekend of Nov 17/18, 2006 to spend 2 nights at the eyepiece of the 82" telescope at the McDonald Observatory near Fort Davis, Texas. ...
NGC 1888, Arp 123, Lepus
Interacting galaxies, the larger edge-on galaxy has the smaller round galaxy sitting right on its central bulge. Not much other detail, but a very nicely framed pair."

But, other northern California amateurs are apparently seeing more detail in this interesting Arp pair. Bob Czerwinski reports:

2/3/03 - A Night at Fiddletown - (18" Starmaster)
...Next in Lepus was NGC 1888/1889, near the border of Orion. Now I've seen 1888 before; it's relatively faint and elongated NW-SE, but odd'ish looking. 1889, which I'd never logged before, is actually a small bump on the east side of 1888, very faint and tiny, but which explains that odd look to 1888. Took a while for me to appreciate 1889 being there.

Robert Leyland, using a 17.5" f/5 Dob, describes his impressions at Lake Sonoma:

...An easy star-hop from IC418, is a galaxy pair NGC 1888/1889, one is edge on (1888), the other a small circular (1889) butted up next to the center of the elongated galaxy, looking rather like a Homberg hat. Averted vision separates the two easily adding to the hat-like effect. 1888 is also sharply edged on the side opposite 1889.

These two interesting objects form another one of Halton Arp's "peculiar galaxy" pairs. Both are defined -- according to Wikipedia's interesting (but somewhat jumbled) articles about 4618 and 4625 -- as 'distorted dwarf galaxies' with a spiral structure "vaguely resembl[ing]... spiral galaxies... sometimes referred to as a Magellanic spiral because of its resemblance to the Magellanic clouds." Both galaxies have a nuclear bar from which a single spiral arm emanates. This gives them "an asymmetric appearance... included in the Atlas of Peculiar Galaxies as one of three examples of nearby galaxies with single spiral arms... many similar galaxies have been identified. It has been hypothesized that [4618's] asymmetric structure may be the result of a gravitational interaction with NGC 4625... observations of neutral hydrogen gas in NGC 4618 and NGC 4625 imply that only some of the gas outside the optical disk of NGC 4618 is affected by the gravitational interaction... NGC 4618's one-arm shape [may be] the result of processes that are intrinsic to the galaxy itself." (A better explanation is found in this professional scientific paper by Stephanie J. Bush and Eric M. Wilcots.)

According to Bush and Wilcots, "Asymmetry is a common trait in spiral galaxies and is particularly frequent among Magellanic spirals... The analysis of the H I distribution reveals that about 10% of the total H I mass of NGC 4618 resides in a looping tidal structure that appears to wrap all the way around the galaxy." This is clearly visible in a positive print from the POSS plate, revealing also the nuclear bar. That tidal structure of NGC-4618 can be seen in the POSS2-UK blue plate above, in a field width of about 20 arcminutes, that I used for the illustrating picture of the pair. There are also two H II regions in the galaxy that have separate catalogue numbers: IC-3668 and IC-3669.

Smaller, dimmer NGC-4625, has a single arm, barely visible in the positive print, above; in my negative version, heavily reprocessed and contrast-enhanced, it is much more clearly detected, as shown at left. In addition, there is a small fuzzy speck at the left edge of the picture, within 4 arcminutes of the central coordinates of the galaxy: this is NGC-4625A, which is a new galaxy discovery.

Dr. Harold Corwin, in his correction notes for the Index Catalogue, notes that NGC-4618 and 4625 were also identified in the later Index Catalogue with separate numbers. He writes, in this file:

IC 3667 = NGC 4618, and IC 3675 = NGC 4625. I have no idea how these identities came about, aside from a coincidence of oversight by both Max Wolf (in whose 5th Konigstuhl list the IC objects first appear) and Dreyer. The NGC and IC positions are virtually identical in both cases, and Wolf's descriptions -- liberally sprinkled with exclamation points -- leave no doubt as to which objects he saw on his plate (the correct objects are clearly marked on the print of the plate that I've compared to POSS1). Perhaps both astronomers were becoming bored with long lists of faint nebulae by 1904 and just didn't do the careful checking needed.

Whatever the case, there is no doubting the identities. The second has been noted in several galaxy catalogues (RC1, MCG, etc.), but the first has been overlooked. I suspect that the feeling, on seeing an IC number attached to an 11th magnitude galaxy, was one of disbelief; or that the number must belong to a knot in the galaxy (IC 3668 is in fact such a knot, and IC 3669 is the south-southeastern arm). But this is all speculation, with none of the principals now alive to tell us what really happened.

So, when you see webpages that give the allegedly alternative IC numbers for these two galaxies, now you know that it is just one more instance of the many mistakes and duplications in Dr. Dreyer's catalogues!

The latest official figures for the two objects are these:

NGC 4618: 4.2'x 3.4' diameter; 10.6v mag.; surface brightness 13.3 mag/sq arcmin.
NGC-4625: 1.6' x 1.4' diameter; 12.3v mag.; surface brightness 13.0 mag/sq arcmin.

Oddly, I found the "Deep Sky Browser" pages for the two objects to have incorrect information (with the wrong diameter for NGC-4625 and some magnitude disparities) so I utilized a combination of the the NED and Revised NGC data for this article.

I looked at the pair as a 'defensive action', taken on the morning of Saturday 24 February 2007 at "my site", during unsettled weather. The Moon set at 1:30 am local time, but though the weather had been rainy and cloudy for several days, by afternoon on Friday, a clearing was in progress. Conditions became so much better by Friday evening that even the Moon could not dim the light of many stars in a crystalline sky seen from my San Jose front yard; so I decided to take a nap and then go up and be ready at Moonset: requiring lots of self-discipline in order to resist the urge to stay warm abed. But rouse myself I did, and drove to the mountaintop and set up my equipment just as the Moon disappeared behind an ugly cloudbank at the western horizon. I had intended to work on galaxies in the region of M-44, a project I started several weeks earlier. But scarcely had an hour elapsed when a new cloud mass moved in to the west, and =CLICK!= as if by an electrical switch, the "lights went out" in the constellation of Cancer. An ugly streak of cloud also appeared to the east. Rather than put everything away and drive home unsuccessful, I decided to wait. By 3:30am, miraculous clearing overhead, with darker than usual zenith sky background afforded by residual clouds over San Jose, encouraged me to proceed. So I found an interesting close pair of galaxies in the plot of Canes Venatici in my Sky Atlas 2000.0 and proceeded. (This is why I seldom plan my observing sessions down to a careful list of objects, and also why astro-planning software programs aren't satisfying to me: I want to be able to look where the conditions are best at the moment.)

The atlas did not plot the objects under the Arp catalogue numbers, but their proximity was suggestive. With my 15 mm Expanse ocular, I quickly had the rather asymmetrical looking smudge of the two close galaxies in the field, with my 10" Dob [80x, 49 min FOV, 3.2 mm exit pupil], but there wasn't much detail. I wanted to be able to discriminate between the brightest spots of the two objects and see what could be detected under close scrutiny; in three adjustments of magnification I finally determined that my 6 mm Expanse was preferable to the combination of a narrower field 10 mm Plössl plus 2x Barlow. So, I obtained what seemed to me my best view [200x, 20 min FOV, 1.3 mm exit pupil], and noted in my logbook: "Smaller 4625 - F, ~12th mag * on N edge. Larger 4618 - VL, br, 11th mag * involved, SW edge. Cannot see a connection between gx's." But I still needed a BIT more magnification to perceive more clearly something I was starting to suspect; changing back to the 10 mm Plössl plus 2x Barlow, which has a claustrophobically narrow FOV compared to the Expanse eyepiece -- [240x, 12 min FOV, 1 mm exit pupil] -- I could now better register the brightest region of NGC-4618, writing "central nucleus brightest spot looks mottled". After staring for a long time, I could tell that the mottling was tending to resolve itself as little fluctuating speckles of light, and discerned an extension from the brightest spot of 4618 that seemed to reach all the way to a nearby star, GSC 3021:1218 (10.9 mag.) In order to check and see if the galaxies were connected by an optically visual bridge, I went down in magnification to the 9 mm Expanse [133x, 29 arcminute FOV, 1.9 mm exit pupil] and added the Orion SkyGlow general purpose LPR filter, which often improves some faint detail of galaxies. Yes: the bright regions stood out better with higher contrast; but I really saw nothing significantly present that was not seen also with the 6 mm eyepiece and no filter. However, in the 19 arcminute FOV of the 6 mm ocular, sans filter, I could also see something else: a fine sheen of faint haze around one particular star (shown as the faint halo around the star at farthest left of the sketch, below.)

I saw that phenomenon, repeatedly, with different eyepieces and over a period of time of nearly an hour of intermittent study: a trace of glow around GSC 3023:251 (11.7 mag.), 7 arcmin. to the NE of 4625, and to a much lesser extent, around GSC 3021:389 (12.3 mag.), almost due E. I show this glow around the 11.7 mag. star as a small nebulous halo in my drawing. I was concerned about light scatter; but my scope's tendency to produce scatter had already been tested by me, on a night of good seeing and transparent air, and found not to be perceptible with stars fainter than about 10M. The weather was, however, on this particular night, unsettled, with some clouds forming elsewhere in the sky and moving around during the early morning. The region of Arp 23 looked very clear, though; and the glow was not seen around several other stars of about the same brightness within a half-degree or so.

I wondered if there were other objects there, not plotted on my Sky Atlas 2000.0. Alas, as I found out the after some hours rest at home: no, but by heavily enhancing the POSS-UK blue plate, I brought up some faint background illumination that COULD be what I was detecting -- or, it might merely be a halation artifact. NED does not show any plotted object, so it is probably merely some dust in the region, perhaps reflecting starlight. I made this observation without filters; when I tried to test them, the magnification was too high and the light was diminished; at lower power, the SkyGlow filter did not help, and the UltraBlock made everything very dim. So, chalk this up to one of my anomalous observations of faint glow; nobody should particularly care but it MIGHT be reproducible by other observers who desire to look long at the field.

There are two other galaxies not too far afield (IC-3171 and NGC-4656) but both are about 25 arcminutes away from 4625, to the east: and aren't the ones causing the glow I saw in my 6 mm eyepiece, which has a field of 19 arcminutes in my 10" Dob.

My sketch, above, tries to show the mottling/speckling effect in the brightest region of NGC-4618 (the galaxy to the right) but at the scale scanned for this webpage, it is barely visible. It was rather hard to do a realistic drawing of the extension south and eastward from the central region of 4618 to the 'bright' 11.7 magnitude star; it is less accurate in the results of the scan, and shows up, probably, stronger than I perceived it by eye. The westerly side of the galaxy 4618 was also hard to delineate in pencil, fading as it did, suddenly, to the background: but I did capture some semblance of the asymmetry (which I did not know about beforehand.) And, when I looked at lower power at both galaxies using the UltraBlock filter, I did not see the H II regions; indeed, I did not know about them until I prepared this article. Could I have seen these details if I had known where they were in advance? It's perhaps doubtful; it might have required a larger aperture scope. I also did not note, specifically, seeing the little "speck" to the east of NGC-4625 that is the newly discovered "NGC-4625A": again, I wasn't aware of it while I visually studied the objects, and I have no idea what its visual magnitude could possibly be; not being a qualified academic for registration, I could not download the full paper to read about it, and details are otherwise sketchy elsewhere. There were, however, faint field stars down to 14th magnitude or even lower, so I could have mistaken that speck for a dim star near the outer edge of the galaxy. In fact, I saw too many faint stars to even begin to try to draw them in my quick sketch; I couldn't retain them in memory long enough to make the 20 foot walk to my observing table and try to record them accurately.

Nevertheless, I am far from disappointed by the amount of information and detail that I perceived, with no preconceptions. Here are some other visual observations:

Steve Gottlieb, 17.5" scope, at this link (search by the galaxy names in this long file):

NGC 4618 - moderately bright, fairly large, faint elongated halo with large brighter core which appears displaced towards the north. Unusual asymmetric object with a more extensive halo on the south side. Forms a pair with N4625 8.3' NNE.

NGC 4625 - fairly faint, fairly small, round, brighter core. Forms a pair with N4618 8.3' SSW.

The German amateur astronomer Martin Schoenball, using a 10" f5 GSO Dob, has produced a drawing on his website that you may find at this link. His description states:

NGC 4618: bright galaxy, very odd shape: looks like a curled tadpole, broad main part barely brighter to the middle. A broad arm runs counterclockwise away from eastern main part an gets sharper. A knot lies detached to the south. The whole galaxy is surrounded by a pretty faint, circular halo.

NGC 4625: bright, small galaxy, clearly fainter than NGC 4618, round, featureless.

Another German amateur astronomer, Uwe Glahn, used a larger aperture reflector and reports, as stated here:

16", 225x, [f/6.7]:
dominating 1:3 NE-SW elongated nucleus with mottled structure; its NE-end has some structure to the N; a 2,5' long arm starts on the N-end of the nucleus; the arm is brighter and thicker to its S-end; brightest HII Region IC 3668 is easy to see; a very faint and stellar region is found 45" E of the nucleus.

A beautiful, scientifically useful color image produced by the GALEX Orbiter Ultraviolet/Visible Camera may be found in small scale on this webpage; and here in a larger and more detailed version. An amateur image of Arp 23 may be found on this page of the Grasslands Observatory, done in the late 1990s with a CCD imager by James McGaha and Tim Hunter. Unfortunately, when I tried to get the picture, their server could not deliver it, so I haven't seen as of this writing. This Arp galaxy pair is intriguing, now that I have done so much research about it. I am looking forward to a second visit, with my more powerful C-11 telescope.

I am not particularly proud of the entire experience that I am about to relate below, showing some rather sloppy observing and imprecise note-taking. Hindsight reveals that I should have been much more careful and thorough. And, the object is very small and obscure, so care is advised: this little devil will take some diligent scrutiny if you are armed only with the Sky Atlas 2000.0, which doesn't plot it. I had been working on PNs in Puppis and had prepared by downloading from the Planetary Nebula finder page all of these kinds of objects in the constellation, and had marked them in my copy of the atlas. In the days surrounding the observation recorded here of Minkowski 4-2, I had been observing repeatedly Abell 23, discussed earlier, and had come to be fairly familiar with the surrounding few degrees of field. Luckily, since this sort of memorization doesn't last very long (at least in my case), I found Min 4-2 before my recall faded away.

On the morning of 16 January 2007, shortly after midnight, I had star-hopped northwest from the nearby clusters NGC-2451 and NGC-2477, both of which I had described as being "spectacular" in my logbook, the former having a "superb yellow star" and the latter being fainter but at higher magnification, as wonderful as the former. Moving almost 4 degrees to the NW, one comes to the position of Min 4-2, which might require reference to a deep sky plot for identification. The planetary is a little more than half a degree to the west, and very slightly north, of an acute triangle of similar-brightness stars: SAO 198093, SAO 198104, and SAO 198086: ranging from 6.3 to 6.5 magnitude.

I had earlier looked at a star chart plot on my computer at home, but brought with me a very coarse, wide-scale printout, which covered a field diameter of about 6 degrees. So, when I managed to find what I thought was very likely Minkowski 4-2, I made two fairly careful drawings, recording relative positions. The planetary nebula has a diameter of only 8 arcseconds, and though it has a high surface brightness (8.52 mag/sq arcmin) is rated at a visual magnitude of 12.9, with a 15.12 magnitude central star. It therefore tends to look quite "stellar" and in conditions of indistinct seeing, or with imperfect optics, the object would either be barely visible or not significantly different from the faint stars of the region. However, lucky for me the seeing was "steady, with no wind" so my scope was stable, and the optics of my Orion 10" f/4.7 Dob are good. I could focus on the stars and get clean, sharp images on the occasion of this session.

If I set my computer star chart program to the a reversed and rotated image orientation depicted in my drawing shown here, I believe that the bright dot to the left and slightly below my depiction of the planetary -- noted with a question mark -- is star SAO 198035 (9.4 magnitude); the other star shown to the right and below the planetary seems likely to be GSC 7116:1889 (13.6 magnitude.) The question mark indicates of course that I still wasn't quite sure if I had centered on the correct object. I was using my Orion 12.5 mm Lanthanum eyepiece [96x, 31 min FOV, 2.6 mm exit pupil] and needed more field stars to match the faint dots on my printout, which unfortunately did not have nearly as much detail as the star field depiction created for this particular graphic.

With my 15 mm Expanse ocular [80x, 49 min FOV, 3.2 mm exit pupil] I was able to gain a significant field width; in the second sketch I made note of three little groupings of stars that are seen below what I thought was the pneb. In addition, I added the Ultrablock filter, the exit pupil now being in good operating range. I had the impression that the putative nebula did not dim though some others stars did noticeably. Under careful scrutiny with the 12.5 mm eyepiece, I added the query: "Is there a faint halo around [a] VF * ?"

I wish I had been more specific about the diameter of the 'halo': was it a halo of just a very few arcseconds, within the rated diameter of the nebula? The perception of a 'very faint star' inside it might have been an illusion, however, as I frankly think it's doubtful I could have seen traces of the 15th magnitude central star inside the tiny radius of the fuzz-ball at only 96x; unfortunately my logbook does not seem to indicate that I used even higher magnification, which could have confirmed it. I wonder why I did not do so?  It's frustrating at this late date, six weeks after having made the observation, to realize that I had missed the opportunity. (And, why the heck didn't I check it with the O-III filter? Was I getting "star whacky" and sleepy? This too is an unfortunate oversight. I'd love to be able to write up these reports to show 'what a great observer I am' but here is a clear indication of an inconsistency of mine, forgetting all about what I'd previously learned about planetary nebulae and faint central stars: so "do what I say" and "not what I did"!) My C-11 telescope, using its GOTO function, carefully calibrated against a regional guide star, would be the better instrument for such an observation. Until I get another chance, I feel that my notes do tend to indicate that my perception of the object identified by me as being the nebula was fuzzier and less point-like than the immediate stars.

Now, a careful check of my second drawing against the deep plot from my computer program, showed a similarity. I have oriented the computer plot shown to agree with my sketch: the three areas marked in yellow could be the little groupings of stars that are below the planetary in my drawing, and the green markings likely correspond to the brighter stars notes in the first sketch. As usual with star chart software, a really good match between the brightness of stars on a screen, and what is perceived by eye, is only approximate, due to the binning of star magnitudes in the software program. The pixel size of stars cannot really resolve the fine distinctions of brightness seen by eye. A photograph is better for this purpose, but again: the eye does not see the stars the way any camera or CCD would, due to human spectral response with scotopic vision. And, neither the blue nor red plates of the Deep Sky Survey pictures are absolutely comparable to the eye's detection of relative star brightness, since the images were made with photographic plates that were broadly blue and red sensitive. At some point of star image brightness in any telescope view -- especially with a large instrument -- some amount of photopic (day) vision starts to register color, changing the perception of brightness. The eye/brain's judgment can only be considered rather scientifically unreliable! Furthermore, as I have to negotiate about a 20 foot walk down a rocky slope from scope to the note-taking table, I tend to forget the exact arrangements and details by the time I settle down, pick up the pencil, change glasses, adjust my red light, and start to sketch what I just saw.

The Palomar POSS1 blue plate was used for the large region picture (10 arcminutes square) shown at the top of this discussion. The planetary simply looks similar to other stars; the same is true of the red plate. But, when I downloaded the infrared image from the POSS2 UK survey, I obtained a distinctly different looking object, easily differentiated from the normal stars. This 5-arcminute square picture -- at right -- shows the very different light wavelengths, and boundary delineation, of the nebula, compared to the point-source star images that are blurred only slightly through the gigantic 48 inch aperture of the Schmidt camera. The stars are so far away that their light arrives in coherent bundles, actually consisting of tiny point sources; they appear to have distinct round diameters, larger for brighter stars than dimmer ones, in a photograph, because of both the diffraction pattern of the telescope optics, and the "burning in" registration on the chemically-treated glass plate negative. As you can see, the very brightest stars have "smeared" out to nearly the diameter of the planetary; but in reality, their light bundles are very much narrower.

Please note also that in the picture above, you can form a triangle with the planetary and two nearby stars; but this very small triangle is NOT the one indicated in green in the sky plots and sketches above. The triangle of stars in the closeup image done with the infrared plate is only about 1.5 arcminutes along its widest side; the triangle marked in green, above in the sketch/plot comparisons is a much larger arrangement of stars that are further out, being about 8 arcminutes on its widest leg. And, of course, the pneb is at the intersection of the vertex in the eyepiece drawing, not at one of the sides, as in the different closeup triangle immediately above.

This evidence has been fairly convincing to me that I've seen the object, though I'd prefer to check it again some time with my C-11 using its GOTO function, after carefully calibrating it on a fairly bright regional star. Here is another interesting observing report, by Kent Wallace (long-time planetary nebula enthusiast, who has published a gargantuan Word file of 418 nebula observing reports):

This PN was discovered by Rudolph Minkowski in 1948. Field Description: At 62.5X, stellar, requiring the O-III filter and averted vision. Good response to the O-III & UHC filters. No response to the H-B filter. At 100X, can see the PN as a faint star with averted vision alone, requiring the O-III filter to identify it as a PN. At 200X, the PN is still stellar. There is a faint star just north of the PN. Observed at Navaho Flats on 10/27/90, 02/23/92, 02/24/92 & 01/26/93 by Kent Wallace using an 8" f/10 SCT.

I believe that the "faint star just north of the PN" reported by Kent is GSC 7116:99 (14.1 magnitude), which is about 51 arcseconds to the north and very slightly east of the planetary. In an 8 inch scope, that star would be "faint".

I found on public Internet websites no other reports, nor pictures; one will probably find some, searching private forums such as the Yahoo Planetary Nebula group. But, let's face it: for visual observers, this object is (dare I say it?) a bit BORING: not nearly as rewarding, in a 10 inch scope, as a nice juicy big annulus or glowing orb with crisply burning central engine. Still, we do what we have to, in order to satisfy the craving for faint fuzzies.

I found that the Deep Sky Browser page did not create a particularly effective finding chart for this object; so below is my own, with far better star positioning accuracy and dimmer magnitude limit.

0.5d/2d Eyepiece View Chart: upright, correct

There are very slight differences in J2000 coordinates for the various designations of the object represented here, which is a fairly large (2 minute diameter) reflection nebula, associated with the visual magnitude 10.3 star HIP 26327 (GSC 4778:1367), which has the odd spectral type B8-A2eq[T], classified in the Hipparcos catalogue as an "unsolved variable which does not fall in other categories" according to the GUIDE software program. The Hubble Guide Star catalogue describes it as a "T Tauri star of spectral type A or B". The star's exact J2000 coordinates are 05h 36 m 25.43s RA, and -06d 42m 57.7s dec., and it is located about 1d 16m to the SSE of M42's trapezium.

NGC-1999 was originally discovered by (you guessed it!) William Herschel, using his famous 18.7 inch aperture "speculum" in 1785. The bright nebula associated with the star was given the designation H IV-33 and is therefore sought by observers doing the complete Herschel 400 list. I never "do lists" and am not interested in checking off objects, one by one, merely because they are in a specific catalogue or group. My preferred sky investigation is to point my telescope at a region where, at the moment, there is least light pollution, generally trying for objects near their time of transit. On the night of Saturday 17 March 2007, at "the site", I was using my C-11 GOTO telescope for one of its first observing sessions of the year, for generally I don't utilize it in the midst of winter due to high humidity that could fog the corrector plate. But fairly higher than normal winds prevented that, and the sky was noted as being very clear, though doubles of 2 arcseconds were a blur.

As usual for my desire to avoid being prejudiced, I did not read anything about NGC 1999 before looking at it. I found that with my 9mm Orion Expanse eyepiece [311x, 12 min FOV, 0.9 mm exit pupil] the object looked like a "v br halo around ~10th M *, no filter. Halo has striations/uneven texture." In his notes for the object on the NGC/IC Project page, Steve Gottlieb commented that in his 17.5" scope, "There is a prominent curved irregular dark patch or globule along the west side of the central star which is striking at high power"; he does not report seeing that with his 8" scope. I had not read that comment and saw only the official NGC description given by my star chart software ("* 10, 11 inv in Neb") and thought I saw "striations" and uneven nebulosity structure, I did not perceive them clearly enough to isolate a distinct 'dark patch', which shows up dramatically in the processed version I created, from a 10 minute square download of the region via the POSS-UK2 survey (blue plate); but unfortunately the star itself is swamped by the burned-in registration of the nebulosity. I suspect that the small dark region it may be more easily seen with a general purpose broadband LPR filter like the "DeepSky" or "SkyGlow" models. But the nebulosity was so bright in my 11" scope that I felt no need to try one out, as I was intent on moving to M-87 to work on a project to try to observe its 'jet'. I will try to revisit NGC-1999 again and test the object with filters and other magnifications. Since it's a reflection nebula, a narrowband filter won't be ideally suited: but it might make the dark patch more distinguishable.

The morning of Sunday, 18 March 2007, approaching dawn, was a rare winter occurrence at "the site" of heavy fog, seeping far inland and clobbering the light pollution from Morgan Hill and Gilroy. It was as dark as pitch near the eastern horizon, but I could also detect a vague layer of fog that had been forming for some time previously, visible all around me at the horizon and probably starting to encroach on my mountaintop site at 3,400 feet altitude. So I was not surprised that the stars as high as 30 degrees were shimmery and soft. But the sky contrast was now greatly improved from my norm of a naked-eye magnitude limit of somewhere between 5th and 6th magnitude. Time to look for nebulae!

I had spent the previous 90 minutes working on M-87's region, to try to detect the famous "jet". When I thought I had achieved as much distinctness as the sky would yield, I sought a few nebulae and dark regions as dawn approached, getting a very good view of the Rho Ophiuchus nebula, which is usually quite invisible from my locale, even though the field of view of my C-11 scope is intrinsically narrow and really rather unsuited to viewing large swathes of the Milky Way. My final object of the morning gave me a very distinct thrill, as the view was so particularly good: the planetary nebula IC-4593, not especially well known to the average amateur, but nevertheless bright and distinct (at a rated Mv=10.8: not exactly the faintest of fuzzies, and certainly detectable with a much smaller telescope aperture.) But the high contrast afforded by very little light pollution enabled me to have a better than usual view of the outer shell that could be detected by eye.

The nebula's rated diameter is 13 by 10 arcseconds. It has a very bright "central" star -- HD 145649, or NSV 7526: 10.2 Mv -- which is actually located a bit offcenter from the nebular region, to the SE by some 5 arcseconds according to the software program GUIDE. But, in my various views ranging from 113x to 466x, the star itself was not clearly visible in the bright, dense glow of the inner region of the nebula, which appeared to be an ovoid or elliptically- shaped core, surrounded by a larger, dimmer halo that was rather concentric with the interior region; and also another, very faint shell of tenuous character. Based on my sketch done with a 6mm Expanse eyepiece in place [466x, 8 min FOV, 0.6 mm exit pupil], the brightest interior had an approximate diameter of about <1 by 2 or 3 seconds, with the fainter halo extending out visually (and proportionally) to a larger diameter of 5 or 6 arcseconds, then steeply diminishing in brightness and fading out totally at about an 11 or 12 second diameter, judged from the approximate eyepiece sketch that I made. Nothing further beyond that was detected, other than sky background; I used no filter. With lower magnification, such as provided by my 21mm Stratus ocular [113x, 30 min FOV, 2.1 mm exit pupil], I found that the UltraBlock filter could help reveal the shape of the faint outer halo a bit better than the OIII. This is possibly because the OIII filter was, at an exit pupil of 2.1 mm, slightly below optimal range for a planetary this size, in my C-11. Yet, no filter at all would be necessary to identify the object, unless the sky suffered from intense light pollution.

A very interesting technical paper, "Kinematics of the strange knots and halo of the planetary nebula IC-4593", written by O'Connor, Maeburn, Lopez, and Redmond, published in 1999, may be found here, downloadable in PDF. The authors state that "the striking planetary nebula... has attracted much observational and theoretical interest in recent years. It consists of a complex system of shells and condensations that extend in excess of one arcminute from the variable central star... the bright core is an asymmetrical, 10" diameter, shell within which there is a high density 'rim'... and a highly asymmetrical system of... bright knots superposed on fainter irregular emission... Protruding from this bright core, into the 'inner halo', are what appear to be opposing, collimated outflows, culminating, at ~ 12" from the central star, in lowly ionized bright knots... The inner halo is bounded by a shell that is strongly brightened to the north-west forming an intriguing bulge... Finally, within the south-west segment of the faint, clumpy outer halo there are irregular strings of lowly ionized emission line knots. The outer halo is irregular and may be described as elliptical... its extent [is measured] to be ~ 130" to 120" from a deep [H-alpha] image. It is not centered on the inner shell... As with most PNe, the distance to IC 4593 is not well known. Estimates range from d=1.5 kpc... to d=4.3 kpc... This range of values combined with galactic latitude b=41° places IC 4593 significantly above the galactic plane."

The second page of the paper includes two spectroscopic images, and "a sketch" which depicts very clearly the main features. Those are deeply overexposed in the POSS1-blue plate that I used for the 8 arcminute square picture, above. (Unfortunately, as I preceded to the further pages of the study, my comprehension "dropped off like a rock", not being a professional astrophysicist or spectroscopist! Maybe you, gentle reader, can get more out of it than I...)

It is a bit hard to correlate the views of a dark-adapted human eye, sensitive only to green/blue wavelengths, with the pictures shown in the professional paper, registering wideband light frequencies including the red region. But, I have the distinct impression that I must have seen what is described as the "core", at least something of the "bulge", and what is called the "inner halo", but not the very, very faint outer halo extending outward to 130", which is registered in the red wavelengths. To my eye, as I recorded in my logbook, I saw "2 shells" surrounding the bright elliptical core; there is, of course as noted, a large and faint 130" outer shell, probably invisible to any telescopic observer though not to professional instruments. (My largely magnified sketch to the left, which shows the boundary of the outer visible shell at a diameter of about 11 to 12 arcseconds, is somewhat more detailed, with fine lines and gradations, than the scan was able to reveal.)

I would very much like to observe the object again, in seeing that is steadier. Even the presence of greater light pollution would not hamper a highly-magnified view of the central core. It would be interesting to know if I could, then, discern more of the details shown in the "sketch" in that paper cited above.

Steve Coe has made a detailed observation of the object, using his 13" f/5.6 Newtonian, which is found here. He finds that it is one of the "blinking planetaries" whose nebulosity will appear with averted vision, and disappear with a straight-on glimpse. (I did not really notice that effect, but I wasn't TRYING for it, nor expecting it.) He says, "This planetary has been called the 'while-eyed pea' and I see why, the nebula is light green and the star is as white as Spica. Averted vision makes it grow about twice its size and there is some very faint outer nebulosity seen." To my aging eye, there was no trace of color at any magnification or exit pupil. At a subsequent observation, Coe says that "averted vision makes the disk grow three times what it is with direct vision." I was using a combination of both techniques, of course, and changed magnification several times. At the highest power (466x) the outer faint shell, the somewhat brighter interior one, and the distinct bright core seemed quite stable no matter how I glimpsed it.

A final note: this object was discovered by none other than Mrs. Williamina Fleming, on Harvard College Observatory plates that she examined in 1907. Mrs. Fleming's contributions to astronomy, of course, are dear to my heart, as I was the first -- in modern times -- to uncover the long buried information that it was she who had discovered the Horsehead nebula!

Wolfgang Steinicke's Revised NGC data page describes this object as a "Diffuse Nebula or Supernova Remnant, type EN"; the website article on Orion's nebulae on the "Atlas of the Universe" page identifies it as a type E (emission nebula.) Yet, querying SIMBAD, it is identified as a "Reflection Nebula", as I had thought it to be for some time in the past. In fact, the object is listed as "RK68" in the "Catalog of the reflection nebulae" by Rojkovskij and Kurchakov, published in 1968 (see this ADS citation; unfortunately the catalogue is not available online.)

The fact that my star chart software program, in use on the night I was observing with my C-11 at "the site", also called IC-420 a reflection nebula led me to investigate it visually without a filter, and then only to use an Orion SkyGlow LPR filter, which improves contrast of reflection nebulae that are whitish-bluish by transmitting a wide spectrum of light, save only a restriction of mostly the frequencies of sodium vapor streetlights. A narrowband filter -- such as the Orion UltraBlock, or Lumicon UHC -- would be a poor choice for a reflection nebula, because the lower frequencies are cut off almost entirely. So, what IS the spectrum of IC-420? I can't find a paper about the object on the Net, nor even a reported visual observation by an amateur astronomer in public webpages.

At least a general hint as to the answer was provided by my research with DSS images, a week after my observation with a telescope. While preparing to write this entry, I downloaded the POSS1 blue and red plates centered on IC-420. A very faint registration of nebulosity was visible on the blue plate, even without any reprocessing, which shows up beautifully with a few steps of mid-tone luminance enhancement; but the red plate showed only a few stars surrounding the bright one in the center that 'excites' the nebula. Heavier processing than I used on the blue plate for the 8 arcminute square picture at the top of this section, yields with the red plate -- shown here at right -- only the faintest trace of anything above the plate grain and sky background. So: it's not a red nebula, and likely therefore does not radiate any weaker H-beta (usually found as a weaker secondary radiation of HII regions, in a greenish- color wavelength to which the dark adapted eye is somewhat sensitive); apparently the choice of the SkyGlow filter was entirely correct.

As is my wont, I had chosen this object because the sky in the region of the constellation of Orion was significantly darker on the night of Saturday 17 March 2007 than regions in the other directions of the compass; although my view was cut off by the mountain ridge, I suspected that fog had crept in, blocking some of the light from Watsonville and Monterey, to the south of my location at "the site". I had set up the GOTO C-11 telescope during daylight, the second trial of the year and one in which I wished to work out a few kinks that my equipment had displayed two nights earlier. During astronomical twilight I used the program "RTGUI" by Robert Shaeffer (a very nice freeware telescope database/controller application) to observe double stars, testing his new Version 8. At the end of twilight, I began observing deep sky objects in earnest, and after a cursory look at the Trapezium region of M-42, I began looking for faint and obscure objects in the region. IC-420 was not plotted in my Sky Atlas 2000.0, but it showed up in my star chart software. By about 9:35pm, I was beginning to study it.

My sketch, at left, shows the aspect of the nebula in the best view I achieved. My logbook records this: "Suspected with 25mm [Orion Ultrascopic: 111x, 28 min. FOV, 2.5 mm exit pupil] with SkyGlow [Orion LPR filter]. Better with 17mm [Orion Highlight Plössl: 164x, 18 min. FOV, 1.7 mm exit pupil]. Better still with 12.5mm [Orion Lanthanum: 223x, 13 min. FOV, 1.3 mm exit pupil] + SkyG." I tried other eyepieces and recorded the following: "VF! Had to slew E-W several times to see boundaries of nebulosity. Barely seen in 9mm + SkyG [Orion Expanse: 294x, 1.0 mm exit pupil]. Not seen with 15 mm [Orion Expanse: 186xm 1.5 mm exit pupil] with or w/o SkyG." (I might add parenthetically that this ocular is not nearly as good as the 17 mm Highlight Plössl with respect to light transmission efficiency.) "Brightest spot of neb'y with 9 mm is about 1'40" WNW of SAO 132229." The overall 'official' diameter of the object, is 250 arcseconds, or just over 4 arcminutes. My sketch may not be entirely accurate but it does show that the brightest spot is to the immediate west of the star.

To determine the exact magnification I used for the drawing, I opened the star chart software I had been using, set the date and time and orientation to agree with the C-11 for the occasion of the original observation, and then switched various "FOVIs" (field of view indicators) until I got a good match. The screen capture shows how the object looked on the star chart program with mirror-image orientation and the pole pointed to agree with my drawing; I had been using my 12.5 mm Lanthanum for the view shown in the drawing, for a view with 223x magnification. Judged from the POSS picture, above, the isophote plot for the nebula is not quite large enough, and my drawing tends to show nebulosity further to the S and W of SAO 132229 than as indicated within the purple boundary.

The star right at the center of the POSS picture at the top of this section is SAO 132229, B9 type, Mag 8.8 (also known as Hipparcos 25954, Mv=8.15.) According to information given in the program GUIDE, the star is a "periodic variable, type B7III", more specifically an SX Arietis type variable, a star that is "blue hot with uneven distribution of helium and strong magnetic fields. As they rotate, the amount of helium seen in the spectrum and the intensity of the magnetic field appear to vary, while the brightness changes by about 0.1 magnitude. These stars, also called helium variables, are high-temperature versions of the Alpha CVn stars, (a class of variable stars [which] show small changes in brightness caused by the star's rotation. One side of the star is slightly different from the other, and as the star spins, the brightness changes from .01 to .1 magnitude.)"

If the nebula is a reflection type, as designated by Rojkovskij and Kurchakov, then the light seen nearby is reflection of starlight, rich in ultraviolet frequencies most likely, from SAO 132229, causing the dust in the region to reflect or scatter the light (the short bluish wavelengths being more efficiently scattered by the cosmic dust particles than the longer wavelength red light frequencies.) This would mean a similarity between the reflection seen in IC-420, and the bright nebula M-78, also in the constellation of Orion.

The nebula IC-420 was discovered on a Harvard College Observatory photographic plate on June 27, 1888 by Mrs. Williamina Fleming, as reported by Professor Edward C. Pickering in the 1908 Harvard Annal publication found here as a PDF document, courtesy of the NGC/IC Project. (This paper refers to the same date that Mrs. Fleming discovered the detail of the Horsehead nebula in IC-434 from Harvard plate B2312, as published in Harvard Annal 18, p. 115.)

Unfortunately, in the original first Index Catalogue, Dr. Dreyer ignored ECP's notice as first given, attributing the discovery to Mrs. Fleming, and identified the discoverer as "Pickering", as may be seen here in this reduced view of the original catalogue page, where I have highlighted IC-420 as well as IC-434 (the nebula upon which the Horsehead was discovered by Mrs. Fleming): both and others here are INCORRECTLY attributed to "Pickering", while the Harvard notices all credit Mrs. Fleming (you may see the original page in full-scale here.) Thus, IC-420 is yet another object "lost" to Mrs. Fleming due to Dreyer's unaccountable actions!

This is most unfortunate, as Edward Pickering did make true and notable discoveries, not from the later Harvard photographic program, but earlier, by visual examination with Harvard's telescope and spectroscope: in fact, 15 NGC and 2 IC objects, according to this article. But also, William H. Pickering, Mrs. Fleming, and others in subsequent years made many more, by examining photographic plates made at Harvard and in the Arequipa Observatory maintained by the college.

It seems to me that IC-420 is an interesting, neglected object: since it was so definitely visible to me in an 11-inch aperture Schmidt-Cassegrain in an only fairly dark sky, south of San Jose, I would think that owners of 8" reflectors (and possibly even smaller, high efficiency refractors of high quality) could see it as well.

Since it is not plotted on all atlases, nor in every star chart program, I offer a finder chart for those who might be curious.

0.5d/2d Finder Chart: upright, correct

The next time you look at the famous interactive pair of galaxies known as "The Antennae" (NGC 4038/4039), be certain also to move your scope about 38 arcminutes to the southwest, and check for Arp 22. I did just that, observing this less familiar Arp galaxy pair at "the site" with my C-11 telescope on 16 March 2007. As is my wont, I looked at them "cold" with no prior attempt to study pictures or descriptions, so that I could make my own unbiased observation.

The Arp 22 galaxies are part of the "NGC 4038 Group", containing as many as 27 galaxies spread across the constellations Corvus and Crater. The official specifications for this Arp galaxy interactive pair are these:

NGC 4027: 3.2 by 2.4 arcminutes; 11.6 vis. mag; 13.3 mag/sq arcmin surface brightness; classification SB(s)dm
NGC-4027A: 0.9 by 0.6 arcminutes; 14.92 mag (p); 14.05 mag/sq arcmin surface brightness; classification: IB(s)m

Thr redshifts are very slightly different, as are the heliocentric radial velocities. The main member of this Arp pair, NGC-4027, is an unsual galaxy: one-armed, in fact. An interesting 1992 scientific study of these objects, "NGC 4027 - an interacting one-armed spiral galaxy with a warped ring" by Phookun, Mundy, Teuben, and Wainscoat (which may be accessed here) explains that "NGC 4027 itself appears to be surrounded by a ring... consisting of gas torn out from NGC 4027A in previous orbital passages. The ring is warped and inclined to the plane of NGC 4027...The companion galaxy NGC 4027A appears to be undergoing severe tidal stripping, as evidenced by a stream of gas being torn out of it." The authors state that "what is known about spiral structure rests mainly on observations and analyses of relatively few galaxies, usually very well-studied paradigms like M51 and NGC 3198. Some spiral galaxies are, however, different enough that it would be unreasonable to extrapolate to them an understanding based on such paradigms... We have chosen to study a small number of galaxies that stand apart from classic two-armed spiral galaxies, but are not so strange as to defy classification and, possibly, explanation." NGC-4027 "is a luminous southern spiral galaxy that is notable not only for its one-armed appearance, but also for its prominent, off-center bar, and the interaction suggested by its proximity of NGC 4027A... About 4'.3 to the south... a late-type galaxy. Its major-axis diameter is less than a third that of NGC 4027, and its blue luminosity... is about 1/19th... There is no bridge or apparent optical connection... but the distention of the disk of NGC 4027 in the east, the closeness of the two galaxies, the similarity of their recession velocities, and the extraordinarily high Hα velocity dispersion in NGC 4027... are suggestive of interaction."

"...There is considerable uncertainty in the distance of NGC 4027... [de Vaucouleurs] use several indicators to arrive at a distance of 10 Mpc... [at that distance] NGC 4027 would be a subgiant spiral galaxy." In April 1991, the authors used a near-infrared camera on the University of Hawaii's 2.2 meter telescope to produce a deep exposure, revealing an H I bridge connecting the two galaxies on the eastern side (not visually registered in optical wavelengths in the Deep Sky Survey plates done either at Palomar or in Australia.) "The most likely process by which NGC 4027A could have fallen within the tidal influence of NGC 4027 is through dynamical friction with dark matter... The companion must have begun spiraling in the dark matter halo before the onset of tidal stripping." The paper is worth a read even for non-astrophycist amateurs, if only for the interesting isophote charts, and the model of the tidal halos of the two galaxies, which looks remarkably like the old "CBS eye" logo.

So, while you stare at these two objects in your scope, remember that you are looking at a monstrous gravitational 'machine' ripping out into space a huge cloud of ionized hydrogen, exerting enormous forces on the two passing galaxies. I was, of course, completely ignorant of all this, on the early morning of Friday, 16 March 2007, at "the site". I had never seen the objects nor even a picture; since I've never done a "Herschel 400 List" hunt, I was also unaware that the main galaxy of the pair is frequently observed by Herschel enthusiasts (it is object H II-296, for those of you who are intent on completing your Herschel 400.) The great astronomer discovered the galaxy in 1785 with his "small" (18.7 inch aperture) reflector telescope; but he mistook the object for a "partially resolvable" globular cluster with faint stars to 16th magnitude. In the pertinent page for the galaxy on the NGC/IC Project website, Steve Gottlieb gives the following description, based on his observation with a 13" telescope: "fairly bright, round, moderately large, broad concentration, possible stellar nucleus. A mag 14 star is off the ENE edge 1.0' from center. A spiral arm is suspected north of the nucleus trailing to the east."

Apparently I did almost as well, using my C-11, for my own logbook states, "Shape? Not clear, but spiral suspected." I also could detect NGC 4027A, which I described in my sketch as being "VF!" I also noted my confusion about a star shown within the isophote plot of the galaxy: "TheSky 6 says 6.2 mag star GSC 6097:754 on gx: no, nothing that bright actually visible." This is also confirmed with the older version 4 of TheSky; but the program GUIDE shows no such star. In fact, if you select the Guide Star "find" function and type in "6097 454" in the search box in that software program, what comes up onscreen is NGC 4027. I think that this shows that TheSky's databases mistake the GSC designators for "non stellar" objects and plot them as stars, duplicating whatever other deep sky object database is also turned on: thus, the spurious showing of a 6th magnitude non-existent star "inside" an 11th magnitude NGC galaxy. But, why "6.2 Mag"? That, I can only intuit by guessing. There ARE some stars visible in the region of the galaxy's halo, as well as the bright central bar. Could it be that the Guide Star Catalogue has listed the 'bar' as being a 6.2 magnitude "non stellar" object, distinct from the galaxy itself? Most likely... after all, the point of the Guide Star Catalogue is to be used in pointing the Hubble Space Telescope. So, the information of greatest use is the position and the magnitude of guide objects, not other characteristics that would be important to astronomers. This is just one more frustration causing one to be badly confused when trying to use star chart software at the telescope: what is shown onscreen is not always what you will see by eye.

My logbook sketch is reproduced here, showing that even though I had to walk away from the scope, and sit down and draw from memory what I had just seen about 10 to 15 seconds earlier, I managed to get most of the field stars in the right general positions (although you must realize that my scope's image orientation reverses the picture right-to-left, compared to the POSS-UK2 blue plate image shown at the top, cropped to a field width of about 12 arcminutes.) The eye view that I have sketched is based on using my 9 mm Expanse ocular [311x, 12 min FOV, 0.9 mm exit pupil]; my records indicate that I also viewed it with my 6 mm eyepiece at 466x, finding a "VF * nr. NGC 4027A." That star would probably be about 2 arcminutes to the east of the faint companion galaxy: 15.1 magnitude GSC 6097:1328; I haven't drawn it in the sketch.

In order to see if 4027A was also visible at lower power, I changed to my 15 mm Expanse ocular [186x, 21 min FOV, 1.5 mm exit pupil] and noted in my book that "At first not seen. Then added SkyGlow filter, slowly slewed scope across field. Saw it!" This is just one of many experiences I've had with a general LPR filter -- restricting only the region of sodium vapor streetlight wavelengths -- that allowed me to get enhanced image contrast with certain faint galaxies. Usually it works best with low- surface- brightness large diameter ones; this time it helped a very small diameter object.

To provide a photographic comparison with my drawing of 4027, I have downloaded the less burned-in UK2 red plate, and smoothed it a bit, reversing and rotating it to agree exactly with my drawing, and show it as an inset. A question I can't precisely answer is the nature of the left-most "point" of light in my drawing of the interior center of the galaxy. Is it a star, as shown in the Deep Sky Survey picture -- being just to the left of the the central bright nuclear bar -- or is it a pinpoint-brightest zone of light in the nucleus itself? (The photo was done in red light; the dark adapted eye is of course more sensitive to blue/green.) There is also another galaxy in the field, about 4 minutes to the west of a center line one might draw between the two Arp galaxies: 1SZ 108 (PGC 37806), rated at 14.8 magnitude: a very "tiny" galaxy with no specified dimensions, which shows up as a stellar speck of light in its DSS picture. I probably did indeed view it, but felt that it was merely a very, very dim star, and did not remember it when making my sketch. A 'stellar' sized galaxy of that magnitude would indeed be within range of my scope, at that magnification and image scale.

There are many public web page reports of sightings of NGC 4027, and I am by no means embarrassed with what my eye gleaned, compared to a few that I have read. Jeff Burton, using an 8" Schmidt-Cassegrain, found that "At 91x... NGC4027 appears as a small, oval, very faint, diffuse patch of light with no discernible central core. The galaxy is somewhat wedge-shaped with averted vision." I was surprised by this, as the central region of the galaxy was so distinct to my eye, and in the photographs, that I would have imagined that it would show up as a bright spot with a smaller telescope. Yet, even with a 10" scope, Ralph Marple saw only an "Elusive hazy area" at 94x. On the fancy and elegant "Herschel 400 Observing List" website Darrel M. Dodge, using a 9.25" telescope, describes 4027 as being "At 60x, pale oval, with even light across disk. Almost PlN-like." (I presume he meant to say, "Planetary nebula-like"?) And, the inimitable Ron Bee, whose usually very colorful and uniquely worded observations depart in their style from almost anybody else's, was able to spot 4027 with his TeleVue 102mm aperture refractor, describing it disappointingly here as being merely an "Extreme dim smudge". A drawing of NGC 4027, done by the Japanese observer Kiminori Ikebe with a 12" Dob, is found on this webpage, but fails to show very much at all other than field stars and the faintest trace of part of the central region of 4027, and nothing of the companion. However, a fine photograph done by means of a 14.5" f5 Newtonian with hypered Tech Pan 2415, located here, shows even more detail of the central structure than the DSS images. The picture was produced skillfully by the very familiar Martin C. Germano (whose photos have been published numerous times in Sky & Telescope over the years.) Finally, with much more aperture than my telescope, observer Mark Birkmann used a 30-inch Dob in a rural Missouri dark sky site, reporting that "It had the appearance of a spiral galaxy with only one arm that curved around until it almost pointed back at the central part of the galaxy. The straight part of the arm had a constant brightness along it's length and then started to dim where the curved part of the arm began. A star was located in the gap between the end of the arm and the center. The central part of the galaxy was brighter than the arm and showed some brightening toward the core." But, oddly, he does not indicate seeing the companion, NGC 4027A.

Little to see in an amateur-sized scope here, but lots of things for professionals to investigate! For near the bright star shown in the lower left corner of the POSS1 blue plate picture nearby (a 30 minute field) are many objects: two IC nebulae (of which relatively few things are known even now); V883 Ori and other variable stars (plotted by the Herbig, Bell "Third catalog of emission-line stars of the Orion population"); LDN 1641C (a dark nebula); Several Haro emission-line stars: 4-248, 4-444, 4-443, 4-440, etc.; some extremely faint Kiso emission line stars; star clusters identified by the Russian astronomer Pavel P. Parenago; and so forth. Indeed, depending on where you dig for your most obscure information, you could turn up a description of IC-429 (the extremely bright speck right at the center of this heavily-processed picture) as a "galaxy" (most authorities don't agree with that) or as a reflection nebula (as shown in this table of objects in the constellation of Orion, or by its alternate name GN 05.36.2.) IC-430 is frequently identified as a reflection nebula, or as one that, under its modern official catalogue nomenclature, is of "unknown nature". So, just what the heck are we investigating here?

According to Dr. Harold G. Corwin's notes for the NGC/IC Project, here is historical information about the two nebulae when first discovered:

IC 429, a small cometary nebula found by [Stephane] Javelle, is indeed involved in IC 430 as supposed by Dreyer. Javelle actually saw and measured only the "head" of the nebula, while the fainter "tail" stretches off about an arcminute to the southeast. This is reasonable, recalling that Javelle was observing with a 30-inch F-23 refractor. (Be sure to click on the link on Javelle's name, to see the magnificent classical Greek architecture of the Nice Observatory!)

Modern identifications of this nebula include PP37, V883 Ori, and Haro 4-13a (my thanks to Dave Riddle for this information). It is part of the star formation complex around the Orion Nebula (M 42 = NGC 1976).

IC 430, discovered photographically by [Williamina] Fleming on two of four plates covering the region of the Orion Nebula and reported by Pickering in Harvard Annals XX, No. 6, 1890, is just where Fleming puts it. This is the nebula that Wolfgang [Steinicke] originally listed under the number IC 429.

The Deep Sky Browser page for IC-429 is rather confusing, for instead it brings up IC-430. But my star chart software programs differentiate the two nebulae. In case anyone is still unsure of which object is which in the POSS plate, above, you may click on these small thumbnails provided by the NED search engine: IC-429, IC-430. As you may confirm from the latter picture, the larger IC-430, which is generally rated at 14.4 magnitude, having a diameter of 11 x 11 arcminutes, is the 'wavy' part of the picture, looking almost like an ocean wave cascading onto the shoreline in the closeup photo link; the old IC catalogue description, decoded, works out to "nebula band 10' little (advanced); long (adjacent), north preceding star 5th magnitude." The smaller IC-429 measures a mere 40 arcseconds in diameter, according to the Nebula Databank by Erik-Sven Vestings (but as you'll read below, I disagree, finding it somewhat larger); in the IC it is given the not very certain description, "very faint, very small in angular size, round (involved in following -- eastward -- one?)"

Needless to say, these obscure objects are NOT very bright in a typical amateur-sized telescope view. I observed them both at "the site" with my GOTO C-11, a little over an hour before midnight on Saturday, 17 March 2007. My notebook does have a very simple and spare sketch of just enough details to help me identify IC-429. My notes state, "IC-429 detectable : slightly br spot, maybe ovoid or irregular, right on region plotted by TheSky 6. 9 mm [Expanse: 311x, 12 min FOV, 0.9 mm exit pupil], no filter. Maybe ~1' on long axis." I changed eyepieces and experimented with filters, later writing, "Also seen with 25 mm [Ultrascopic: 112x, 28 min FOV, 2.5 mm exit pupil] and OIII filter; but NOT with UltraBlock filter. 11pm: ending; now down pretty low." I have taken the POSS picture, rotated it to agree with the orientation of my scope, and pasted it next to my drawing: a good match.

Just before zeroing in on the narrow region of IC-429, I looked at the larger nebula IC-430. I did not make a drawing, as it was just so tenuous in the eyepiece field that it would be hard to indicate on paper: any mark I might make would be too distinct. I wrote, "very vaguely seen: uneven barely glowing region by SAO 132411, ~10-12' NW. Used 25 + OIII [112x as shown above]; UltraBlock no good. SkyGlow: maybe helps a little." The bright star in the field does diminish one's ability to see the faint nebulosity. It is also known as 49 Orionis and Hipparcos #26563 (at 05h 38m 53.09s RA, -07d 12m 45.8s dec, J2000 coordinates), Mv=4.7, type A4V. In the SAO catalogue it is rated at Mag 4.88, spectral type A3: a spectroscopic binary with a massive invisible companion, according to information in the GUIDE program.

Since the UltraBlock filter (a "UHC" type) did not help, but rather tended to extinguish both nebulae, one can be fairly certain that there is little or no visible light from the nebulae in the H-beta wavelength at 486.1 nm (this is the weaker secondary radiation of H II regions.) On the other hand, the OIII filter did seem to be somewhat effective at the lower power/wider field view with the 25 mm eyepiece; but I'd suggest that you start looking for the nebulae WITHOUT any filter.

There are very few observations posted on the Net. I found two succinct commentaries by Steve Gottlieb, from his survey of the NGC and IC objects:

IC 429: 18" [telescope] (1/21/04): this cometary nebula appears as a very weak, small enhancement, ~10" diameter, about 2' NE of a wide pair of mag 13 stars located 13' NW of mag 4.8 49 Orionis. At moments appears stellar or an extremely faint star is involved.

IC-430: 18" (1/21/04): very faint, fairly large low surface brigtness glow to the NW of mag 4.8 49 Orionis, ~4'. Extends to a wide pair of mag 13 star. This reflection nebula needs to be reconfirmed as the bright star may have confused the observation.

I hate to say this: but I disagree with Gottlieb about the apparent size of IC-429. If it's 2' from the two stars he mentions, then as my picture shows, it is far larger than 10 arcseconds -- and it looked that way to me. I measure those two stars as being separated by 1' 19" using TheSky 4; the nebula is located about 3' from a line connecting those stars. As my drawing shows, corroborated by the DSS picture inset, and the NED 5-minute square thumbnail, the bright region of IC-429 might indeed be as much as an arcminute long; certainly it's larger than 10 arcseconds.

A friend has kindly provided me with a screen-dump picture of the display in GUIDE, with the isophote plot mode turned on; you may use it as a narrow-field finder chart (upright, normal) to try to find the nebulae, around the bright star SAO 132411. Consult the Deep Sky Browser page to create a wider field chart.

1d Finder Chart: upright, correct

Haffner 23: Open Cluster
RA: 07 09 30.26    Dec: -16 56 11.1
in Canis Major

Quick, here's a quiz: give the first name of the astronomer who catalogued the "Haffner" open clusters! I'm waiting... waiting. Time's up! No, "H" will not do. You lose this round; thanks for playing.

I have to admit that I lost the round, too. For after about an hour of searching databases, articles, and the Net, I finally had to admit defeat. For, the not totally obscure astronomer H. Haffner (8 Nov 1912 - 23 Feb 1977) of the University of Würzburg, seems not to have been willing to publish his first name! In countless references in professional papers, in databases, and in websites, it's always just "H." As soon as I solve this mystery, I'll be certain to update my article, as I like to take the trouble to put in details that are usually glossed over by other articles in amateur astronomy literature (for instance: where else would you learn the full name of "Francis Gladheim Pease"?)

Along the way, I did manage to turn up the original catalogue of Haffner, in German, and decipher a little bit of it. But, I'm getting ahead of myself. The reason that I looked into these relatively minor objects is due to the constellation tour by Sue French in the March, 2007 issue of Sky & Telescope, in her regular "Deep Sky Wonders" column. The article "Bark with the Overdog" (pp. 66-68) covers in her typical manner a small 'intimate' region of sky that yields a wide variety of celestial objects, some familiar, some obscure, including these two Haffner clusters. I enjoy going through each month's tour, even if I become quite frustrated by the disparities of the lists she uses, compared to the ones available to me. One perennial problem I've confronted is the inclusion of one or two interesting double stars, which Sue identifies in the "classical" manner according to the original star catalogue number. Few of MY star chart programs will accept the numbers and return the stars. Often I can't find a corresponding conversion on the Net, and sometimes her coordinates differ slightly from my planetarium software, landing me in a spot that is only within a few arcminutes of what she probably intended to signify. I wrote to her last month and asked if she and the magazine would be willing to add an alternative SAO number for, at least, the primary member of those doubles (which all tend to be bright ones, and thus found in modern catalogues.) The answer: no, the editors don't think that is necessary or appropriate. Oh, well: back to the "hunt and peck" method of location...

But, at least in the case of this object, Sue's information was "right on", and my star chart software was significantly off. At first, I used the coordinates given for Haffner 6 in my softare program; but when I typed those into the SIMBAD search engine for producing a Deep Sky Survey picture, the cluster was almost off the edge of the resulting field. But when I used her exact numerical coordinates, what came up was a nice photograph with Haffner 6 nearly perfectly centered. Bravo! So, use Sue's (given above) and you'll find Haffner 6.

The Haffner clusters are sometimes included in a few star charts, and one or two may occasionally be plotted in software. A deep Net search for the complete original catalogue by Haffner yielded his "Neue galaktische Sternhaufen in der südlichen Milchstrasse" (New Galactic Star Clusters in the Southern Milky Way), published in 1957, in German, in Zeitschrift für Astrophysik (Vol. 43, p.89): here's the link to the ADS page, where you may obtain a download in PDF. I did that, and read through the short paper as best I could, with my barely-remembered college German. The introduction is in English, and states:

"27 faint cluster-like objects have been identified on 10" Metcalf plates taken in Canis major and Puppis... 22 of them are galactic clusters with high probability... The apparent photographic magnitudes of the the brightest cluster stars range from 13 to 16 mag. Provisional distances are estimated to be 4.4 kpc for most of the objects. It is argued that the clusters belong to the spiral arm extending in 210° longitude."

I got the gist of the paper from the German text without resorting to one of those messy, inaccurate online translators (which can't cope with scientific terms, especially in German!) Essentially, the paper explains that the plates were obtained by means of the 10" aperture Metcalf triplet refractor (coma free field of 3°) of Boyden Observatory, Bloemfontein, South Africa, in November and December 1955, on Kodak IIaO plates (format 20x25 cm, extending over 9 by 11°). All plates were exposed for 30 minutes during a period with the objects closest to the meridian. The objects were checked with the Palomar deep sky survey plates, where available, and also with plates taken by Tombaugh at Lowell Observatory; Trumpler's and Tombaugh's papers on open clusters are cited. A table is given of 27 items, with J1950 coordinates. All of these clusters were included in the familiar "Catalogue of Open Cluster Data" (1987/1995) by Gosta Lynga, Lund Observatory, Lund, Sweden (available online here.) A really good and complete star chart program will incorporate all these objects; unfortunately not every one does. I had to combine the screen outputs of two different programs to make up a finder chart, given below.

At "the site" on the evening of Tuesday, 13 March 2007, I observed the objects in Sue's tour in a leisurely two-hour session with my 10" aperture Orion f/4.7 Dob, starting at 9pm. Sue describes Haffner 6 thusly:

"The small open cluster Haffner 6 is centered 22' east-northeast of Thor's Helmet [NGC 2359, which I describe in this article.] Thoroughly inconspicuous in my 10-inch reflector, Haffner 6 is a 7' group rich in extremely faint stars, and it could be a nice target for a large telescope. As you might expect from its minute stars, Haffner 6 is a remote cluster; it's estimated to be 10,000 light years away from us. It's also a very aged one, estimated to be about 670 million years old."

Sue gives a rating of 9.2 visual magnitude at a size of 7 arcminutes diameter. The program GUIDE, according to a helpful friend, says on the other hand that the diameter is 4 minutes, and at a distance of 1100 pc, with the brightest stars being mag 16 (age 79,000,000 yrs.) What did I see in my telescope?

As usual, the little chart given in Sue's article each month is -- frankly -- rather frustrating and hard to use. But, after some searching I found what assuredly was the object she described, moving over from Thor's Helmet. My logbook records that I used the following eyepieces: 7.5 Lanthanum [160x, 18 min FOV, 1.6 mm exit pupil], 9.0 mm Expanse [133x, 29 min FOV, 1.9 mm exit pupil] and at best could could perhaps see "~12 VF *. Shaped like a little house?" I think that if you look at the center of the POSS2-UK telescope blue plate image (above, in a 20 arcminute field centered approximately on the cluster) and perhaps squint a little bit, you can tend to see something that resembles a 5 or 6 pointed star shape, or at least a kind of "object" that has at the top, a 'tilted roof' with apex pointed at the upper left hand corner of the picture.

In fact, to show it at all with any clarity, I "cheated" a little bit. After I had resized the original image (which was far too big to use as a web page picture) the stars had become rather soft. As usual, I slightly sharpen them, but this time I sharpened ONLY the region of Haffner 6's stars. That way, they seem a bit brighter and clearer than the background field. Frankly the result seems to me to have the same kind of distinction that the cluster has when you view it with a good telescope in excellent seeing, at the magnifications I used. It isn't really a dramatic or very definite cluster in an otherwise barren sky, because the field is peppered with faint stars. But, it was not hard to match Sue's description to what I could see in my eyepiece.

That same evening, I viewed another Haffner cluster given in the Sue French article: Haffner 23. I was much more impressed, rating it a " ! " in my logbook. It was best viewed at very low power, and I recorded viewing it in my 21 mm Orion Stratus eyepiece [57x, 70 min FOV, 4.4 mm exit pupil] and in my brand-new Orion Q-20 2-inch barrel 32 mm [37.5x, 112 min FOV, 6.8 mm exit pupil]. It looked more impressive because, according to GUIDE, at a diameter of 11 arcminutes, the faintest stars are 13th magnitude. But, ironically, it did not look like much at all, when I first downloaded a 30 arcminute square field, centered on SAO 152475, a magnitude 9 type A0 star that is approximately at the center according to the plot in GUIDE, but actually a bit to the south of the 'real' center. One can barely tell from the raw scan of the UK Schmidt blue plate that the stars associated with the cluster are not merely random field stars; again, I tried my trick of highlighting them by means of selective sharpening. A liberty? Yes: but it helps make the photograph seem closer to the 'real' experience.

Here is Sue French's description:

...move 2.4° west-southwest [from cluster NGC 2360] to Haffner 23. At 47x my 4.1-inch scope shows 30 faint to very faint stars lossely sprinkled across a mottled background about 13' across. The coordinates generally listed for Haffner 23 give the position of the brightest star, which shines at 9th magnitude. Visually, the cluster's center appears to be a few arcminutes northeast of this star.

Finally, I was sorry that neither of those masters of open cluster art, Jaakko Saloranta and Jere Kahanpää, had included a drawing on their respective websites. I did a lengthy, frustrating web search, and then checked all of my own astro links, which contain some fine websites with astronomical drawings, but came up with NOTHING. No amateur has drawn either one, and posted them in an indexed public webpage, to my knowledge. But, I did find an interesting professional scan/drawing by R. P. Fenkart, found here: it's a map of Haffner 6, which I located on the WEBDA Home Page ("A site Devoted to Stellar Clusters in the Galaxy and the Magellanic Clouds", the "Web version of the database known as BDA.") On the Navigation Page you may enter the name of the object desired. I thus obtained the pages for Haffner 6 and Haffner 23, which you may find to be of interest. Various charts and maps are available, plus other data and papers. Happy Haffner Hunting!

Haffner 6 - 0.5/2.0 d Finder Chart: upright, correct

Haffner 6 - 0.5/2.0/4.0 d Finder Chart: upright, correct

Obscure, faint galaxy challenge: not one, but two, in fact! If I could see this galaxy (shown in the DSS image to the left, slightly below and right of the center) in an 11-inch telescope located not much more than a dozen miles from my house in San Jose, California, then I would expect that innumerable deep-sky trawlers with big iron could get it, too; possibly along with a fainter galaxy that should be visible in the same eyepiece field. If I can do it, you can too.

Forget about finding this in most star charts or planetarium software. Some of the advanced programs show it, if you set the galaxy magnitude limit way down low: this object from the Principal Galaxy Catalogue is given, per one reference, a photographic magnitude rating of a dim 14.1, with a surface brightness of 14.2 (in magnitude per square arcminute.) But I found that this rating is actually rather high; other sources, such as Hyperleda, give it a range from 14.25 to 15.92; the NED search engine page rates it at a mere 16.27 magnitude (none of these figures has been converted to visual magnitude.) At a diameter of 1.2 by 1.1 arcminutes, it's a bit more distinct than many other "faint nothings" in the PGC that show up in large telescopes when the sky transparency and background darkness are sufficient. Indeed, as Anthony Ayiomamitis the deep-sky imager said once in a post to sci.astro.amateur, if memory serves, you can turn on your CCD and capture such things as this, plus "a whole 'nother level" of galaxies, mostly uncatalogued, in only a few minutes. Pity that the dark-adapted human eye doesn't work that way...

The galaxy may be obscure -- as seen in the POSS1 blue plate, cropped above to a diameter of about 10 arcminutes -- but it is large and bright enough from Earth's vantage point to enable large telescopes to detect some significant detail. I took a 2x2 minute scan from the DSS picture, and subjected it to horrendous amounts of iterative smoothing/sharpening by various means. Some of the detail I've brought up may be spurious; but you can see from the original image, on this page, that it is suggested from the raw data. I calculate the distance (given the redshift value of 0.012417) to be 52.43 Mpc, or about 177.5 million light-years. As a comparison, the Virgo cluster of galaxies, many visible in the smallest aperture amateur scope (and thus discovered by Messier in a small refractor) is about 59 million light-years away (18 Mpsec.) When you look at this little faint smudge of light in an amateur telescope, you've really accomplished something! Not many other people on Earth have used a "time machine" to look back this far: when the light you see left this galaxy, the Earth was experiencing the Cretaceous Period, the time of the origin of mammals and birds, and the appearance of flowering plants. Makes you think!

All of this occurred to me not while looking at the object -- astronomical viewing is too stressful and intense an activity to encourage much of that sort of cogitation -- but while researching what precious little information is known about the object. My logbook for the night of Saturday 17 March 2007 records merely that I used my 12.5 mm Lanthanum eyepiece [224x, 13 arcmin FOV, 1.3 mm exit pupil] and put a tentative "maybe" on the observation, to check later. I wrote that PGC 17232 was "EF, AV (averted vision)" and that I "moved field over w 12.5 - [PGC] 147434 quite obvious, smaller/brighter. At steady moments suspected star on or nr gx." (That would be a bit hard to determine from this description. At about 2 arcseconds due west, you'll find GSC 4761:714, at about 14.8 magnitude; or I could have seen an even fainter star that is not in the Guide Star catalogue. PGC 147434 -- which is 4'58" northeast of larger- diameter PGC 17232 -- also has a GSC designation, 4761:720, 15.6 magnitude.

On the PC I use for making up these articles I have two very old star chart programs, and neither one made much sense of the eyepiece sketch, though one of them did show the galaxies: no matter how I turned and oriented the screen display, I simply could not match them convincingly. So I fired up the laptop that I used for the original session, to send the control signal with the centering coordinates to my GOTO scope; resetting the date, time, star chart's screen display for 'reversed E-W' and orienting the pole in the correct direction, I was able to get an almost exact match, save that my "FOVI" (field of view indicator) for the scope+eyepiece combo was a bit larger diameter than my drawing; and perhaps some of the stars near the center/right of the field aren't exactly in the proper places. As I've said before, I have to leave the scope and stumble down from a rocky incline to the table and PC, fifteen feet away; change eyeglasses and move my eye patch, take up pencil, and only then draw what I remembered.

Frankly, this is not a particularly interesting object to look at, nor even to describe so painstakingly, recounting every detail of the observation. I could put in dozens -- hundreds -- of such observations into these articles, if I wanted to; just a few examples like this will suffice, however. I cannot remember ever going after a SINGLE item from the PGC before getting my GOTO C-11 in 2005; years before that, when I had a 17.5" Dob, objects of this size and magnitude would show up, but the scope was so unwieldy, and the focus so poor due to optical aberrations, that I paid no heed to them. And, who could identify any of these obscure, pesky little beasts? The modern integrated starchart-GOTO scope system, however, if properly aligned and calibrated, makes it possible to find them in a much less efficient light gathering instrument: an interesting challenge if one is so inclined.

For those of you who are interested in sky catalogues, the Principal Galaxy Catalogue is made up of all of these various lists and compilations of objects, and may be queried by means of Hyperleda. If you'd like all the low-down, here are the links via Hyperleda to PGC 17232 and PGC 147434.

I won't bother to make up a finder chart; you could use my close-up eyepiece plot immediately above, in conjuction with a wider finder prepared from the Deep Sky Browser page's chart-making capacity if you must have one; unfortunately I can't seem to get it to list the second smaller galaxy of the two discussed here.

IC-591 or UGC 05458: Spiral (Sbc) Galaxy
RA: 10 07 27.75    Dec: +12 16 25.7

PGC (LEDA) 213668: Galaxy (S?)
RA: 10 07 23.71    Dec: +12 14 44.6
in Leo

Here are "Obscure and Obscurer" (with apologies to Jim Carrey and Jeff Daniels.)

I found the galaxy IC-591 on the night of my last observation of the faint dwarf galaxy Leo 1, using my C-11 telescope at "the site" on Wednesday 14 March 2007. This fairly faint IC galaxy was not hard to locate, as it is only just under 23 arcminutes to the NW of the well-known bright star Regulus. If you can figure out what is the exact center of the very dim, tenuous Leo 1 (hard to judge visually) then all you need to do is move 14'45" due west: and you're at IC-591. I would guess that it could just barely be seen with careful observation in an 8 or 9" telescope, given a very dark and transparent sky. It was not that challenging in my more efficient C-11, even though my naked-eye stellar limiting magnitude wasn't better than 5.8 to 6.0 at the zenith; I was observing this galaxy around the time of its transit for best visibility.

But, I see today from my work preparing this report that I missed something: : the galaxy shown in the POSS1 blue plate picture, above, that is cropped to a diameter of about 8 arcminutes. For the small galaxy below IC-591 (i. e., about 2 arcminutes to the south-southwest) wasn't visible to me. My struggle to obtain data about it suggests I could have seen it. Unfortunately, it did not show up on my laptop's star chart program, so I did not "strain" to see it. One can conclude that either it just was not visible; or that it was so close to the threshold of detection that only diligent searching, with the EXPECTATION of finding it, could yield it with my scope. I'd think though that a 17.5" instrument would show it with little difficulty.

So, the report here is both a successful observation, and a failed one. I did not make a "discovery" of a real object, in the eyepiece field. It would have been nice to report that I had done so...

First: the brighter, larger, and more obvious of the two galaxies. IC-591 has a total corrected B magnitude of 13.85; if I run this figure through Matt Oltersdorf's Visual Brightness Calculator, I come up with a figure of Mv=12.7, with a surface brightness of about 12.8 magnitude per square unit. Other processes yield slightly different values: Mikkel Steine's Deep Sky Browser page reports "14.1p" and "surface brightness is 13.9". His page gives the diameter as 1.3'x0.8' (the Revised NGC data), but Hyperleda says 0.96' by 0.19', which anybody would reasonably round off to 1 by 0.2 arcminutes. 'Closeup' pictures here suggest at least a three or four to one ratio but my own processing and composite (of the detailed interior from the POSS1 blue plate, added to the heavily enhanced outer halo), would I suspect prove that the galaxy's ratio of wide to narrow diameters is surely less than the 5:1 specified by NED; therefore, don't expect an extreme on-edge object.

The galaxy's redshift is 0.009470 +/- 0.000010; by one particular mode of distance calculation, it would therefore be about 39.99 Mpc away from earth, or 130,429,935 light-years distant. Please note that Mikkel Steine's Deep Sky Browser plot, as well as some astro software, shows a big 'star' in the center (GSC 833:934, non stellar, 13.2 mag) but this is a spurious display, and is instead the Hubble Guidestar plotting center for the object. Don't expect to see a bright star 'in' the galaxy.

My logbook does not contain an eyepiece sketch, but my brief observing report for IC-591 says: "VF oval. Seen with 21 Stratus [113x, 30 min FOV, 2.1 mm exit pupil] or 15 Expanse [186x, 21 min FOV, 1.5 mm exit pupil]; almost invisible in 9 mm Expanse [311x, 12 min FOV, 0.9 mm exit pupil]." Since it shows up at merely 113x, which is for me the normal "medium low power" eyepiece used with my C-11 telescope for finding fairly large diameter objects, I would consider this galaxy to be quite conspicuous: for other galaxy observations in my logbook, I've used the abbreviations EF, EEF, and even EEEEF!

The tiny, faint galaxy to the south of IC-591 is quite easily discerned in the POSS picture (above) but is neither plotted by my star chart software (none of the various different programs I use, in fact) nor was seen by me even in the 9 mm eyepiece field. The object is PGC (LEDA) 213668, alternately identified as 2MASX J10072368+1214442, 2 minutes away from IC-591, and measuring 0.8' by 0.4' photographically. According to Hyperleda's page for the object, the total corrected B-magnitude is 15.74; processing this by Matt's calculator, I yield Mv=14.7. Color and monochrome images are here. The redshift (0.052107) with equivalent conversion as done for IC-591 suggests that the distance is 220 Mpc. or 717,609,262 light-years: it's a long way from Earth. Mikkel Steine's Deep Sky Browser database at www.Messier45.com does not recognize either the PGC number or the Two Microwave All-Sky Survey (2MASS) designation; nor does the star chart program GUIDE (which, according to its online documentation, has only 160,000 of the over 900,000 objects in the PGC.) No version of "TheSky" that I've tried shows it onscreen; yet these star chart programs do show even fainter galaxies. It is, however, resolved by Hyperleda as an actual object.

The problem, I suspect, is that the PGC database used in various star chart programs has either not been updated to the 2003 edition, or leaves out quite a few of the galaxies. Hyperleda, however, has 1,551,560 objects, incorporated from 50 galaxy catalogues: the PGC plus another half-million objects. Some of these are indeed visible in typical amateur scopes, since many advanced observers have 17 to 24 inch, or even larger, Dobs. Galaxies that show up in the POSS pictures are therefore usually identifiable via Hyperleda, if not your typical star chart program. Since PGC 213668 might be as bright as 14.7 visual magnitude, next time, I'll try to nab it visually.

But, IC-591 is the more interesting of these two objects. It was discovered by eye in the late 19th century with a 30" refractor by Stephane Javelle, one of the most prolific contributors to the NGC and IC, who is given a nice illustrated webpage by Wolfgang Steinicke. I did find one observation on the Net, in a long text file on the NGC/IC Project site, done by Steve Gottlieb:

IC 0591 = UGC 05458 = MCG +02-26-025 = Todd 22
10 07 27.8 +12 16 26
V = 13.1; Size 1.0x0.7; SB = 12.6; PA = 170d

17.5": faint, small, slightly elongated, even surface brightness. Located 15' W of dwarf galaxy Leo I in the same 140x field (35')!

The reason that galaxy is identified as "Todd 22" is explained here by Steinecke. In reading this and other references I learned that American astronomer David Peck Todd (1855-1939), one of the NGC 'discoverers' and considered to be a distinguished scientist at the turn of the twentieth century, graduated from Amherst in 1875, received his PhD in 1888, and became director of the Amherst College Observatory. At Amherst he began studies of the the motions of the planets and their satellites; eventually in 1877, based on the irregular motion of Uranus, he began searching for a trans-Neptunian planet, a study that influenced Percival Lowell's interest. Todd used the 26" refractor of the U. S. Naval Observatory in Washington in 1877-78, and later studied photographic plates, without success (of course, the "dwarf planet" Pluto, that alluring trans-Neptunian object, had to wait for Tombaugh's discovery in 1930.)

Todd's very interesting college astronomy textbook, "Astronomy; the science of the heavenly bodies", published in 1922, is now out of copyright and may be downloaded in a variety of formats, or read in your browser, via this link at the Internet Archive (I've read a bit of it, and shall go back for more.)

According to Wolfgang Steinicke, Todd made 8 contributions to Dreyer's NGC. One object is spurious; one is a duplicate observation of another object; one was discovered earlier by William Herschel; and IC-591 -- credited to him as "Todd 22" -- was discovered in actuality by Javelle. In Todd's original paper, derived from his observations searching for the trans-Neptunian planet, the astronomer claimed some 30 new "nebulae". Of course, in the days before modern communications, and a decade before even the publication of the NGC (errors and all), Todd can't be faulted very much for his mistakes and 'parallel discoveries', given the state of the documentation of astronomical objects at the time: most "real" professional astronomers of the mid-19th century were concerned mostly with deriving stellar positions, and doing accurate time measurements. Astrophysics was in its very infancy (said to have started only in the 1860s with the spectroscopic work of William Huggins) and nobody was bothering much about cosmology. "Nebulae" were of interest to comet-seekers (as things to avoid) and it took decades for astronomers to begin to achieve real break-throughs in discovering quantities of new ones, compared to the achievements of William and John Herschel: first, by means largely of the "Leviathan of Parsonstown", the giant 72 inch telescope of Lord Rosse, and then through the incipient astrophotographic programs of Harvard and Lick Observatories.

Even today there is not very much interest by amateur astronomers in the vast contents of the Index Catalogue, other than some nebulae that turned up at the end of the 19th century on photographic plat