Why does everything astronomical have to be so darned complicated?  I thought I'd idle away an afternoon, casually adding one more item to my 'faint fuzzy' articles: merely an open cluster. "This should be easy," I thought. "No great astrophysical issues or debates; not a 'threshold' object just above the level of imagination; it has probably registered vividly on the Digital Sky Survey photos. Get the specs; crop the picture; write it up." WRONG! As usual, what I expected to be no more than an hour of joyous work turns into a tedious task, involving much repetition, waiting for unresponsive distant servers, diddling with image processing, and cross-checking data in charts and catalogues, compared to historical publications. Bah!

I should start at the beginning. During the early morning of Wednesday 20 June 2007, the quarter Moon set about 10 minutes past midnight at my locale in the Santa Cruz mountains. I knew from experience that I could really start deep-sky observing about 20 to 30 minutes before that, but I was delayed in getting set up, and exceedingly anxious to confirm the previous night's sighting of Abell 48, which I have described earlier in these articles. After almost two hours' work on that exceptionally challenging faint nebula, I was ready for some relaxation, and after a break for refreshments resumed, looking now at easier objects in a part of the sky where the presence of some local ground fog, far below me, had reduced the usual light dome that washes out contrast. The Milky Way was brilliant overhead, and by naked eye I could see branching, bright and dark clumps, and almost as much "structure" as I would experience from a truly rural sky. It was an almost magical night, with seeing that fluctuated between a superlative 9, and an almost un-heard-of perfect 10 on the Pickering scale: awesome, memorable. The sky transparency was splendid, and telescopic views with my 10" Dob had never been better at this location. When I got to M-11 in Scutum, my jaw dropped open. The steadiness of the air had lifted a veil from the sight I beheld, which sparkled as I had only once before seen it in the last ten years, using my C-11 at a spectacular dark sky sight down the Pacific coast. I could remember only one other view to compare: once, in my friend Rich Page's wonderful Astro-Physics "StarFire" 7-inch apochromatic refractor, the most perfect telescope I've ever used. All the usual stellar distortion artifacts were GONE; I was bewildered at the unexpected ability of my "fast" Newtonian reflector to give such a refractor-like lapidary display: a single overwhelmingly bright radiant point set at the edge of a fan-shape of flawless crystals, like a celestial queen's incomparable jewelry. I'm shaking my head in wonder even now as I try to remember it all while writing this account; it was unforgettable.

Now a certain friend of mine has been known to call me "Mr. Hyperbole" from time to time; may he forgive me this outburst of poetry. The experience really shook me, and still does. I moved the Dob along from object to object, using p. 105 of the new edition of the Uranometria as a guide. Without my GOTO scope, it seemed easier just to proceed from one nearby item to the next, and take them easily in turn.

I surveyed the open cluster Trumpler 35; then the rather ambiguous AL 5, and paused for a while to see if DoDz 32 would sink in (I scratched, "well, perhaps - not sure" in my log.) Then, onward a very short distance to the southwest for the huge starcloud NGC-6682: "patchy with 21 mm eyepiece" at 57x, according to my brief comment. This starry condensation is large, filling much of the rich field of my eyepiece, which yields a little more than a degree in this telescope: there are far too many stars to count. Moving my scope about 1d 40m to the south and slightly east, I came to NGC-6683, just a small round icon on p. 125 (right chart) of Uranometria, Vol. 2, a fraction of the size of NGC-6682. But I was greatly impressed by what I saw, and conveyed it in my logbook.

Nice!! Wedge-shaped grouping of stars (~< 2 doz?) S of semicircle of *s. Neb'y! 21 mm [Orion Stratus, 57x, 4.4 mm exit pupil, 71' FOV]; even lovelier with 9 mm [Expanse, 133x, 1.9 mm e. p., 19' FOV], or at higher power.

I had the distinct feeling that this was a region infused with glow, like the cluster NGC-7510 -- or, to a larger extent, the famous Pleiades, M-45 -- though why, for the life of me, I did not try out filters on it, I can't say. I should have.

After a few minutes, I moved on to look at various "firsts" for me, including some planetary nebulae of the region, and finally spent the final hour before the beginning of twilight looking into Cygnus and Cepheus. But NGC-6683, of several new objects spied for the first time on this occasion, is the one that stands out in memory. I was in fact anxious to look it up as soon as I got home, and to see pictures of it on the Net, which I did -- feeling a bit groggy -- at 5:30 am.

The only image I retrieved, until I began working on this report, was the appropriate object page on the NGC/IC Project (which you may obtain by going to their Public Database and typing in NGC 6683; use no hyphen.) The page that comes up, which I can't link directly here because of the scripting properties of that website, shows a nice distinct DSS picture, with the cluster standing out fairly well in a complex but dimmer field: a profusion of very faint stars registered right down to the photographic grain. The position for the cluster, according to my examination of original documentation files on the NGC/IC Project website, was measured by none other than the esteemed professional astronomer Dr. Harold G. Corwin, the "cleanser" of the NGC: "Positions are the estimated center of gravity of the image on the PSS, and are adequate for identification." I found that this position is a good one, closer to the apparent visual center of the object than the one used by many other references, which seems slightly wrong in declination (more on this below.)

The cluster looks oddly shaped; I really don't know how to describe it based on its appearance in the image shown. We learn from the web page that John Herschel found the cluster in 1827, which means that it was not one of the objects found after 1833, when he took his father's old 18.7 inch speculum telescope to South Africa to chart the southern heavens. NGC-6683 would be relatively low in England, and not seen optimally; but surely well enough, for it is about 2d 12m due west of the "Wild Duck" cluster M-11, so named after the colorful allusion given by the British enthusiast Admiral William Henry Smyth in his Bedford Catalogue (a marvelous old book by means of which I've whiled away many a pleasant hour.) I was surprised to find that the less impressive NGC-6683 (rated at visual magnitude 9.4 at 3 arcminutes' diameter) was not, in fact, one of the "Herschel 400 objects"; based on the very significant impression it made upon me during my view of it on this occasion, I wondered why old Wilhelm Friedrich had not bagged it decades before his son eventually did.

Unfortunately I could not verify JH's original description from his 1833 publication in the Philosophical Transactions of the Royal Society; this is indeed online via the JSTOR website, but one must have a membership to access it. Therefore the earliest information about the cluster that I have at hand is Dr. Dreyer's description in the 1888 New General Catalogue (translated from the code, which I obtained from the very first edition of the catalogue, online here) as being a "cluster, very rich, very little compressed (in Milky Way)." I had to do this the hard way, as I found that numerous modern digests of the old NGC render the code with varying degrees of accuracy, saying that "vlC" as printed by Dreyer, was instead "vIC" or "very little condensed", "very considerably large" or even "very largely compressed". You just can't trust ANYTHING you read in any old astronomy book, list, or chart! (Well, perhaps you should "trust, but verify".) The original edition of the NGC includes neither measured dimensions of the objects, nor visual magnitude ratings.

As usual, the minutely-exact Steve Gottlieb improves on the NGC and gets to the very heart of the nature of the visual appearance of this cluster in his viewing log description, contributed to the NGC/IC Project:

17.5" (7/1/89): about 20 faint mag 13-15 stars in two converging rows in a very rich field. The edge of the "Great Rift" is just 10' W (part of dark nebula B103) with an abrupt drop off of stars!

8" (7/5/83): 10 faint stars in an elongated group over unresolved haze. The "Great Rift" is obvious just 10' W. In a rich field.

- by Steve Gottlieb

There are few reports of the object available for contrast. It is not mentioned at all in the Sky & Telescope compilation of "Deep Sky Wonders" columns of Walter Scott Houston; nor in Sue French's "Celestial Sampler". The renowned expert observer Steve Coe describes it discouragingly: "Seen in 10 x 50 binoculars as a bright edge to the Scutum Star Cloud. Not much in telescope, does not detach itself well from the star cloud." I found it plotted not  in the Gottlieb/Tirion Orion "DeepMap 600", nor in the S & T  "Pocket Atlas"; and not even on the famous "Sky Atlas 2000.0". Why not?! This is a fine object, very much worth viewing.

I am both pleased -- and embarrassed -- to see that it IS included in the open cluster database in my own old software program, "Eyepiece": pleased that John Sanford chose it for his book "Observing the Constellations", whose lists, data, and observations the author gave me permission to use. This suggests that back in the 1980s I had indeed looked at the cluster, as I always tried to view every object in that volume that could be visible from my northern California skies. But I blush at finding that the diameter, and the declination coordinate given there, taken from Sanford, are according to the modern revision, inaccurate. I did not have digital setting circles in those days, and had no way to resolve such a small error! I will add these errata to the list I have on my machine; when it grows a bit larger, I will revise the data for a subsequent update (but not for just this one tiny mistake, especially as SO MANY OTHER resources also get it wrong, as will be discussed below!) However, it was very easy to correct the master list of clusters in that program, which is available here on my website; I just corrected the values. In this era of GOTO scopes, there is no point in sending your instrument to the wrong central coordinate (that is, if you are lucky to have such a scope with 5-minute positional accuracy), and expecting to see a larger sized object than is really apparent by eye.

Now, the next frustration in my perusal of source material. When I attempted to get a scan of the Palomar and UK deep sky survey plates in order to produce a picture for this article, using the STScI Digitized Sky Survey website, resolving the coordinates for NGC-6683 via SIMBAD, the resulting images were all wrong! They confounded me at first, as I could not see the cluster, compared to the quite well depicted images on the NGC/Project website (such as this one.) The pictures I got were just a jumble of faint stars, so many in profusion that I could not find the cluster members at all. At long last, I realized why. The coordinates were off! The Revised New General Catalogue position, derived by Wolfgang Steinicke, places the object at the RA and dec given above in the headline for my article. But, the SIMBAD values were 1 arcsecond off in right ascension, but FIVE ARCMINUTES too large in declination. The cluster was positioned at the edge of my picture. I tried again; and again; each time suffering long, boring delays as the server cranked out the data. But the images had too many stars; it was hopeless. Even though I was now seeing where at least the center of the object was positioned, so that I could crop the larger field, there was no way to differentiate the brighter stars of the cluster -- so readily apparent to me by eye at my observing session -- against the busy Milky Way background. After giving up on various combinations of red and blue plates, ultimately I took a different route, and obtained an image that looked a bit different, with hardly any clarity in the background stars, by downloading the proper coordinates via the SEDS page for the object. and clicking the link for the "Digital Sky Survey Image". It came up wrong too; but I corrected  the position and repasted the values into the URL string: try this instead. The cluster is a bit to the left of center; I cropped the picture to a diameter of about 12 to 15 minutes on a side, which I then further modified and used at the heading, above. The next problem was the nebulosity.  Gottlieb and I both saw it; in the Uranometria Field Guide, the description also says "Involved in nebulosity"; we're all in agreement. But, it did not show up in the normal white stars on black rendering -- at all.

I looked at the negative version of the picture, and decided that -- yes -- it COULD barely be detected. In this version the unmodified negative mode is at left, and the contrast-enhanced one is at right. Frankly I think the nebulosity was stronger to my eye than as recorded in the image; but it was an exceptionally clear, dark, and transparent night, as I stated above. I may not see it that way the next time I try to view the object. I "cheated" a little bit, while producing the picture at the top of this article, and tried some graphics editing tricks to simulate what I saw. I can't assert that it will be realistic on all monitors; it doesn't look too far off on mine (except that in my 21 mm ocular, at 57x, the cluster was very small; in the rendering I made at the top, the cluster is sized the way it would have looked in my 10" scope with a magnification of about 175x.)

I must say that I had better luck observing this object than did Ante Perkovic of Croatia, whose report is here. He says he completely failed to discern it, using a homemade 4.5" Dob. Judging from its brightness in my 10" scope, it would readily have shown up in my comparable small telescope; and it was lower in my sky elevation than it was for Andre. But, oddly, he cites its diameter as being "size 11 minutes" which is 3.6 times too large. ANOTHER discrepancy! For, according to the Revised NGC data by Steinicke it has a diameter of 3.0 arcminutes; this is also the size given in the Uranometria Field Guide by Cragin and Bonanno (which explains its source for open cluster data as having been derived from a list prepared by Brent Archinal and Steven Hynes, augmented by measurements of survey pictures by Cragin.) The cluster appears to have a widest diameter of about 3' in good pictures; indeed, it looked that way to me through the scope, and it does if you click on the link, below at the end of this article, to Jaakko Saloranta's drawing and check it against the stars he has drawn by using the measuring tool of star chart software (Jaakko too specifies it as being 3 arcminutes.) I came upon the object by eye, following the Uranometria chart over from NGC-6682: it stood out to me as a nice, bright little cluster, suffused with glow, which bore even more magnification than 133x, as I reported. If it had been 11 minutes in diameter, at a visual magnitude of 9.4, the sparse individual cluster stars would have been VERY, very faint, indeed! It would have been a much more challenging thing to pick out than I found it to be.

Now, I've never before heard of amateur astronomer Ante Perkovic, who was expecting to see an 11' diameter object, and couldn't find it; he might also have been using the wrong declination coordinate, 5 arcminutes away. Since he had a Dob, this would have been a trivial matter to correct and isn't likely the problem; he probably was trying to conceptualize something nearly four times larger, and not perceiving it!

I discovered while researching this article that the size discrepancy is widespread. The Deep Sky Browser page for the object (which won't show the picture properly centered, as it has the declination error) says "11 arcminutes" too. So does Steve Gottlieb! You may confirm this by reading all of his report for the object on the NGC/IC Project, or by searching through his large textfile of descriptions. All the older star chart programs on my computer also say "11 minutes", as does the last beta (version 3) of Cartes du Ciel, which SAYS in its configuration window that it uses the RNGC by Steinicke, the version of which is dated 2005, according to the documentation files. Yet Steinicke's value is NOT the one that shows up when you click on NGC-6683 for information! The only program I have that uses "3 minutes" is The_Sky VI, which I use to control my GOTO scope. That program employs both a fairly recent version of the Saguaro Database and the Revised NGC; has the correct size, and the proper coordinates; whew! (But, I've found plenty of other errors in the databases for that particular piece of software.)

Corroboration of the Steinicke/Archinal data for the cluster may also be found by perusing the large textfile of open clusters on the Open Clusters and Galactic Structure website of Wilton Dias, et al., which updates the older 1980s catalogue of Lyngå. After a great deal of web-searching, I finally found the query page for the Lyngå catalogue, and looked for the object in the 1985 (pre-revision) version; the table of information indicates that the diameter is "11 arcminutes". I then did a much larger, general search with VizieR, which takes a long time to process if you want to try: click here.

The results were interesting. According to the NGC 2000.0 of Sky Publishing (Sinnott, 1988), its size is "11 minutes". But. in the latest version of Lyngå available from WEBDA, as well as in the "Catalogue of blue stragglers in open clusters" (Ahumada, Lapasset, 1995) NGC-6683 is now 3.0 arcminutes: Houston, we've SOLVED the problem!

I read through the Ahumada paper (online here as a PDF) explaining the survey of this group of 390 open clusters, which focuses on their inclusion of some 959 "blue stragglers" (which in these cases are very old stars that anomalously fall outside the normal Hertzsprung-Russell evolution curve; were the result of stellar collisions and have accreted mass from the instellar medium; and were captured by the clusters.) The data were primarily taken from the 1983 version of Lyngå's catalogue, with supplemental information from many other sources. One blue straggler has been identified in NGC-6683, noted by Turkish astronomer Fatma Yilmaz in a 1966 paper whose title I would translate into English as "The distance of the ring-shaped open star cluster NGC 6683".

I made a cursory study of the German language paper and found that I could answer most of my questions about the data discrepancies that I've observed. In my very casual and approximate translation of the opening paragraph, Yilmaz says something that I believe could be rendered in English as this:

A photometric study of NGC 6683 has not yet existed. The star cluster is remarkable considering that it consists of a circular ring of stars, with many members inside and outside the circle, which shows its form clearly at the edges. That suggests that NGC-6683 itself is only a part of an almost ring-shaped stellar group. For NGC-6683 alone, an apparent diameter of 3 arcminutes is indicated by Reinmuth (1926). The entire ring has on the other hand an external diameter of 11 minutes.

Aha! Karl Reinmuth's paper, cited at the end of the paper by Yilmaz, does not appear to be available via the NASA ADS website archive, so I can't read the original source. I have, however, a speculation about this. I would surmise that Reinmuth may have studied a picture of the cluster -- he found many asteroids after making no less than 12,500 measurements on plates taken at Königstuhl Observatory in Heidelberg, as reported in his 1979 obituary notice, so he was a tireless observer of photographs -- and concluded that it had a 3' diameter in conformance to the brighter stars that could be seen by the earlier visual observers; later, Yilmaz (and subsequent investigators) determined that there was a larger body of faint stars outside the vividly-seen ring that consists of a number between a dozen and two dozen brighter stars. Depending on who had revised the New General Catalogue of 1888, either the total photometric diameter of 11 minutes, or the visual appearance of 3 minutes, was used for the "official" figure.

I have made a graphic of the approximate centers and diameters of the "Corwin" data (which I prefer, matching what I see by eye) and the "Old Lyngå, etc." position (with the 5 minute declination discrepancy, and the diameter that is 3.6 times larger.) You can see how one might well fail to spot the cluster in agreement with the NGC or Gottlieb description, especially with the incredible plethora of faint stars in the field, which don't show up in this image. Use of the larger diameter poses a significant problem: for the visual magnitude could not then be "9.4" based on such a large area containing only a few visible 12th-13th magnitude stars. But it COULD be reasonably given 9.4 magnitude if the area containing those stars was defined by the smaller diameter. Thus, when you use the NGC for visual observations, you should employ a revised version that MATCHES your use and intention; otherwise you'll sometimes be misled, and expect objects to be a different size and brightness than the values given. Steinicke's revision is probably the best list for visual purposes, and it is coming to be accepted by some of the best star chart software and maps. Perhaps an even better solution to the many quandaries presented by the errors of the NGC, and the data changes resulting as modern astronomy evolves, is the intelligent work done by the compilers of the Uranometria Star Chart and Field Guide, Murray Cragin and Emil Bonnano (the latter being the creator and programmer of "MegaStar".)

I was fascinated to discover that the epoch 1950 coordinates given in the Yilmaz paper are incorrect  in declination, which places the center slightly more than 5 arcminutes to the southeast. When precessed to 2000, the declination becomes about 6h 17m, which is the figure that frustrates me, because it is so obviously positioned away from the center of the "star wedge". Yet, many professional catalogues are still using this allegedly wrong reference. Could this be because of the disparity in the two differing data of its diameter?

As far as I can tell without laborious and precise word-by-word translation of the rest of the paper, the measurement of the cluster's distance was determined photometrically in 1965 on a Schmidt plate taken of the Scutum region for other purposes in 1956, using the 36" Heber Curtis Schmidt Telescope at Ann Arbor Observatory (and as Yilmaz explains, "on that plate lies the cluster [NGC-6683] at a distance of 2.5 degrees from M-11, similar to well-known plates used for photoelectric measurements of Johnson, Sandage, and Walquist (1956), making photometry of the cluster possible." As you can see if you click on the link to this marked plot given in his paper, 175 stars were measured.

In order not to violate copyright on the original document I've created my own rough plot of the stars shown in Yilmaz's rendering of the photographic plate for the purpose of illustrating the extent of the stars that he identified. What is immediately interesting about the original annotated negative image of the star field in his paper is where the NGC object proper may be found with respect to the rest of the stars "outside" the ring. The cluster first visually discovered by John Herschel and numbered h2081 is the broad V-shaped grouping of stars "pointing" to the NE, a bit above and to the right of the center of the picture: stars numbered by Yilmaz from 1 to about 24 to 26 (this 3-arcminute diameter assemblage of stars was catalogued as NGC-6683 by Dreyer, and seems to be not really at the center of the position given in the old Lyngå catalogue declination for the "11 arcminute" object including all the stars external to the bright ring.) The Lyngå cluster center position looks to my eye to be slightly to the south and east of what looks like the true center: I have tried to show this in my graphic, with the the original John Herschel cluster inside the light green circle, the center marked with the darker green cross-hatch; the approximate position given in the old Lyngå catalogue is marked in blue, and what I think might be the logical center of group is the red mark (these are approximate and could be done more accurately by a qualified professional.) Perhaps if careful geometric measurement is done, however, the Lyngå coordinates would seem to make more sense for the entire wider group (but not for the 3-minute "pointed wedge" of stars.)

Yilmaz states that it would appear that the star cluster (at his measured distance of 1250 parsec) is arranged in a ring; his study covers an area with a maximum diameter of 11 arcminutes, including all faint members (encompassing many dim stars that won't show up in amateur sized telescopes.) By means of a (now obsolete) three-color RGU photometry measurement it was determined that "The star cluster has practically the same distance as as two others in that neighborhood: NGC-6664 at 1155 pc. and NGC-6694 [M-24] at 1440 pc."

The modern value of the distance to NGC-6683 is now generally given as being 1197 parsecs as shown on this WEBDA page. Here, the picture rendering the object has a total diameter of 10 arcminutes on a side, with the cluster shown perfectly centered, obviously covering a smaller diameter of approximately 3 arcminutes. WEBDA cites many other studies or publications of the object, and I frankly have no enthusiasm for tracking them all down! But my conclusion is that visual amateur observers would find the Steinicke coordinates given at the top of this article -- very similar to Corwin's position -- and the diameter of 3 arcminutes, based on what John Herschel first saw, make the most sense.

The 'certification' of NGC-6683 as a true cluster puts the lie to the claim, which I found in the documentation for the object in the planetarium software GUIDE and Cartes du Ciel -- and the old version 6 of the Saguaro Astronomy Club database that GUIDE relies on -- that "NGC-6683 is thought not to be a true cluster."

As I said, why does everything in astronomy have to be so complicated?

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

UPDATE, 11 July 2007: Well, here's a how-de-do (as William Schwenk Gilbert would have said.) I finally found the original John Herschel publication, in the Philosophical Transactions of 1833, containing his report of recently discovered objects, which you may find as a 21 MB PDF file at this link. And, it would appear that object h2081, which is allegedly equivalent to NGC-6683, is NOT specifically and precisely as described by Dreyer in the NGC of 1888! Sir John Herschel says this: "A more than usually condensed portion of the enormous cluster of the Milky Way. The field has 200 or 300 stars in it at once." Herschel's position coordinate, epoch 1830, is about 30 seconds less in right ascension, and somewhere between 3 and 4 minutes less in declination than the modern value, exactly precessed back to the same date. So, JH's position is closer to what I have called the "old Lyngå" coordinate, represented by the blue cross-hatch in the graphic above. And, the discoverer's description refers not to the dozen to two dozen stars in the "wedge" but to the whole assortment as analyzed by Yilmaz. This makes me suspect that the modern revisions of the NGC assigning the cluster a 3' diameter have tended to be influenced by the Reinmuth paper referenced by Yilmaz. Curiouser and curiouser... srw

And so I have come to accept philosophically that unless I go on a distant astronomical safari, it will never look remotely like a photograph: and hasn't appeared that way with any of my telescopes, even one as large as my old 17.5" Dob. Of course, a rare night does occur when San Jose and Morgan Hill are totally socked in by fog. If I am so lucky as to be present on the mountain, I am much more likely to survey 'dim nothings' completely obscured at all other times, rather than to concentrate on something spectacular, such as NGC-281 or NGC-7635. But the frequent exposure to glamorous color images of the "Bubble" nebula on astrophotographers' webpages has made me much more conscious of the importance of this object, despite its mediocrity in my telescopes. So, in the spirt of fresh inquiry as to what I could make of it, even in the face of adversity, I have revisited it recently during three observing sessions. The most important thing that I learned from this is that I probably needn't bother to try it at "my site"; even driving a few tens of miles to the further-east public sites at Henry Coe Park, or the boat-ramp at Coyote Lake would be enormously beneficial. Though I lose 2,000 feet of altitude, these locations position the worst of the streetlight glow slightly west of Polaris, allowing the constellation of Cassiopeia to shine more dramatically for at least part of the night, compared to my mountain venue. This I would recommend to all south bay astronomers -- and especially astrophotographers -- if they cannot go even farther away from San Jose.

My work on NGC-7635, as reported here, is severely crippled and compromised; so be it. But, some persistence paid off: after several tries, I could see the nebula as well as Jaakko Saloranta has experienced it in his 3" telescope: pretty sad for the user of a 10" aperture instrument, but that's the best I can do, typically.

The "Bubble" nebula, whose name is immediately suggested from the appearance in almost any good deep photograph, was discovered visually by William Herschel in 1787. The New General Catalogue description, first published in 1888 (as shown here), is "vF, * 8 inv l excentric" [sic], which may be interpreted as meaning "very faint, 8th magnitude star involved, a little eccentric". My first small discovery during this examination is that Bob Erdmann, of the NGC/IC Project, seems to have changed Dr. Dreyer's star of magnitude "8" to one of "9"; this may be confirmed by surfing to the NGC/IC database page and typing in NGC 7635 in the search box, using no hyphen.The description given is not exactly as shown in the scan of the original Dreyer publication, but instead "vF, * 9 inv l excentric". I have isolated this change to the first ASCII-text machine-readable hand typed version of the catalogue created by Erdmann between 1991 and 2005: this alteration leapt from the page after I had spent some time examining star charts of the region, taking note of the second-brightest star within the boundary of NGC-7635, which causes the "bubble" to light up. The star is in fact SAO 20575, magnitude 8.4 (also identified in the Tycho catalogue as being slightly dimmer at 8.69, and in the PPM catalogue as magnitude 8.7.) Now, if you have to use a single decimal to describe that star, perhaps "9" is closer to the truth than "8"; this could have been Erdmann's reasoning, assuming he intended to change Dr. Dreyer's abbreviation.

What did William Herschel himself report? I found that Bob Erdmann has indeed CORRECTED a change made by Dr. Dreyer! On page 248 of the Philosophical Transactions of the Royal Society, the 1789 paper by William Herschel -- downloadable as a 15 MB PDF at this link -- reporting his recent discoveries, what we now call NGC-7536 is included as object no. 52 in Class IV, planetary nebulae, discovered on November 3, 1787. As shown here, Herschel describes the object as "A ft 9 m. with vF. nebulofity of S. extent about it". (Of course, one must remember that in the typography of the day, the letter "s" is represented as "f" when joined to other letters in a word; so Herschel says -- in effect -- that the object is a "9th magnitude star with very faint nebulosity around it, extending to the south." It was changed by Dr. Dreyer to "8" magnitude for no known reason; did he look at it, as he had done with many of the objects, and decide to alter the magnitude, or find it closer to 8 than Herschel's 9; or did Dreyer make a simple transcribing error?

"An inconsequential disparity," perhaps you might say. Well, there is a rather huge difference in brightness between an 8th, and a 9th, magnitude star, and a very significant difference between 8, 8.6, and 9. Within 30 arcminutes of the center of the nebula there is in fact one star close to 9th magnitude, SAO 20584 (9.4 v) and it is very distinctly fainter than the star SAO 20575, which excites the bubble of glowing gas. And, the 6.8 magnitude star SAO 20562, almost 6 minutes to the southwest, is comparitively blinding, at least in my 10 inch aperture scope. Its brilliance tends to reduce the apparent contrast of the nebulosity of the region. When looking for the Bubble nebula it is important -- unless you have a pristine, dark sky -- to recognize the brightness differences of the stars in the immediate region, and to focus your attention on the correct one, which is the dimmer of the conspicuous pair of bright stars that you'll notice, about 6 arcminutes apart.

I could not find any information on the Net that would inform me of the origination of the nickname "Bubble" nebula. Since the details are relatively faint to the telescopic eye, even with a fairly large instrument, the discretely sharp-edged bubble effect that is so dramatically evident in photos -- such as this POSS negative view -- might not have occurred to early observers. I thought at once of Max Wolf, the pioneering astrophotographer whose long-exposure pictures showed so many remarkable objects in detail for the very first time. But, the online links to a few of his old papers are preserved in graphics format, so it would not help to look for "blase-nebel" (Bubble nebula in German); and I had no more success than by searching for the name in English. However, I did find a marvelous, historic paper by Edwin Hubble that I first studied back in 1989 in the files of Lick Observatory's historical collection in Santa Cruz. This work is possibly the first modern astrophysical study of the object, and you may download it here via this NASA ADS page.

Entitled "A General Study of Diffuse Galactic Nebulae", the work was written by Edwin Hubble in 1922 and published in the Astrophysical Journal. I had read it carefully in the original volume in order to glean Hubble's data on IC-434, the emission nebula that helps the dark nebula known as the "Horsehead" to show up against the faint milky background glow of ionized hydrogen. Hubble also analyzes many other objects, including NGC-7635.

The great astronomer discusses the then-known differentiation of "extra-galactic nebulae" (now called galaxies) from galactic diffuse nebulae. After summarizing the nebular classifications developed by the Herschels, Wolf, and Curtis, Hubble focuses on diffuse galactic nebulae and arranges them into two general categories: emission and absorption spectrum nebulae. NGC 7635 is found as the last item in Hubble's table of the emission-line type nebulae.

His measurements, based on plates he took with the 60-inch reflector and Cooke 10" astrograph at Mt. Wilson, discerned three hydrogen emission lines, and one at 3727 (O II). "NGC 7635, formerly known as a nebulous star, appears to be a large planetary immersed in diffuse nebulosity. The brightest portions of the non-planetary nebulosity give the emission spectrum described." His results indicated that the object did not radiate the "normal ratio" of planetaries, but instead strong Hydrogen-beta, matching IC-434 (which he describes as "the remarkable Bay nebula stretching south from ζ Orionis, whose sharp edge is indented by a dark cloud billowing out from the obscured region." Hubble of course means the object now commonly called "The Horsehead nebula".)

Referring to NGC 7635, Hubble writes that "Of the six giant planetaries [...the term...used to describe those with diameter greater than 2'. There are six such planetaries...] only one, NGC 7635, shows the stronger Hβ, and the same ratio holds for planetaries out of the Magellanic clouds...The most striking examples of these latter, N.G.C. 40, I.C. 418, N.G.C. 4361, and B.D.+30° 3639, are in no way exceptional in appearance or in their nuclear spectra. The nuclei, however, are unusually bright as compared with the general average."

Hubble does use several "popular" names for a number of the nebulae, including the Cave, Dumbbell, Helix, Owl, North American, Crab, and Trifid -- not to mention the obsolete "Bay" (meaning the Horsehead) -- but he does not give any nickname for NGC-7635.

The most impressive modern image I've seen, which is not in color but is spectacularly detailed, featuring rare beauty, in monochrome H-alpha light, is this one done by musician/astrophotographer Eric Mouquet (it is also found on his website with informative details given in French.) But the Hubble Telescope image, credited to Dr. Donald Walter of SCSU, has more scientific and astrophysical significance. The "Astronomy Picture of the Day" article by Robert Nemiroff and Jerry Bonnell summarizes current understanding of the object:

What created this huge space bubble? A massive star that is not only bright and blue, but also emitting a fast stellar wind of ionized gas. The Bubble Nebula is actually the smallest of three bubbles surrounding massive star BD+602522, and part of gigantic bubble network S162 created with the help of other massive stars. As fast moving gas expands off BD+602522, it pushes surrounding sparse gas into a shell. The energetic starlight then ionizes the shell, causing it to glow. The above picture taken with the Hubble Space Telescope and released last week shows many details of the Bubble Nebula never seen before and many still not understood. The nebula, also known as NGC 7635, is about six light-years across and visible with a small telescope towards the constellation of Cassiopeia.

The nature of the Wolf-Rayet star (BD +60°2522 mentioned above) is succinctly explained by Rob Gendler in this article, which complements his exquisite picture, done by means of a 20-inch Ritchey instrument.

William Herschel wasn't wrong in classifying the object as a "planetary nebula" by his criteria; but thanks to the findings of Hubble, and later astrophysicists, the Bubble nebula is now considered to be a 'diffuse emission nebula', and due to the strong ionized hydrogen radiation, was catalogued by Stewart Sharpless as the galactic HII region 2-162.

But, yes: the Bubble nebula IS certainly visible with "a small telescope" as asserted in the APOD webpage; and the proof is this drawing done in 2007 by my friend Jaakko Saloranta, which you may find here. Jaakko employed his 8" Dobsonian to make the sketch at a magnification of 122x, in a sky offering a naked eye magnitude limit of 5.9, observing that it was "Beautiful but faint and complex. Indeed bubble-shaped. Brightening in the W side from the 8th magnitude 'central' star. Fainter wisps can be suspected in the N and SE side from the main nebulosity with UHC filter." But Jaakko has also seen the object several years earlier, offering a drawing posted here: for this picture, which was done during conditions of aurora, which affected sky contrast, Jaakko had a rather contemptuous description: "Nasty. Rather faint, somewhat small nebulosity close to a 9th magnitude star. Only visible with adverted vision. Forms a curve, or letter-C around the bright star. O-III helps, object a bit bigger and brighter." Furthermore, he indicates that the "minimum aperture" to detect the nebula is in fact only 3 inches! And he has explained to me that when he asserts this in his lists, he's actually DONE that observation himself: in this case, with his 80 mm aperture Konus f/5 refractor.

I have never tried to see the nebula with one of my very smallest aperture scopes, but I could claim that there was at least some slight trace of a difference in the background illumination of the star region in my 9x60 finderscope, on the night of my last observation. I tried to hold my UltraBlock filter up to the eye lens of the finder, but the test was hopelessly ineffective and unconvincing. And my sense of seeing some trace of the milkiness of the region might merely have been due to the proximity of all the stars in nearby M-52, plus the countless faint sparklers across the finderscope's field of view.

I made one drawing of the Bubble nebula during the last of my three tests in summer 2007; but of course I was hopelessly prejudiced by having seen photographs. Furthermore, I looked at Jaakko's better drawing earlier in the spring, and had it fixed well in my mind; he did such a good job in his April 2007 study that I could add nothing to it. Eventually I believe I finally glimpsed, at least momentarily, traces of all the details he records here, but they were by no means steady and reliable (especially the 'inner curve' of the bubble.)

I see that I have neglected to give the revised NGC object data so that you may prepare yourself to see the right kind and size of object. The latest figures are these: diameter of 15 by 8 arcminutes (longer axis from the NW to the SE), with a visual magnitude that is not given a universally accepted rating. I have found figures that vary from 6.9 (absolutely wrong!) to 11 or 12: a very wide latitude indeed. This is in fact rather hard to calculate, given the extreme variations in nebular density, so no single number is really convincing. Likewise, surface brightness is seldom specified, though I found one webpage that claimed a mere 15.94 magnitude per square unit of area: but since this can only be an average value, it's not particularly informative. Steve Gottlieb has estimated in his NGC notes that the visual magnitude might be approximately equal to 10.5, which seems to me to be a good compromise; but Steve doesn't give that figure in his Orion "DeepMap600", which omits the rating altogether. Years ago John Sanford rated it at "12+" magnitude in his book OBSERVING THE CONSTELLATIONS, which supplied the objects and data for my computer program "Eyepiece". When I added the object to the database, I changed it to be "~12" back around c.1993, but now I might tend to think that it's closer to Gottlieb's value. No magnitude is specified in the NGC revision by Sinnott, though Wolfgang Steinicke's Revised NGC attributes a B Magnitude of 11, but no visual magnitude rating. And, the latest version of the Uranometria employs the ratings of Beverly Lynds, which for this object are, at best, ambiguous: it shows up better on red than blue DSS plates, though the brightness ranges from highest to lowest values possible, depending on the position measured by photometry. Let's just say that the NUMBERS are all pretty unimportant to visual astronomers, and not even particularly relevant to amateur astrophotographers. It's an object that is very faint in most regions, and requires sensitive equipment and generous exposure times.

I recall that early in my experiences with my new C-11 telescope, during the summer of 2005, I looked casually at the Bubble nebula but made no specific notes about the object. So my observing session of Thursday/Friday, June 14/15, 2007, was my first careful study, taking notes, since the 1990s. It was a very long night, commencing at 9:45 PM in conditions described as being "warm, calm, clear, very steady" and continuing until morning twilight at 4:40 am, with 31 objects logged and described. To give you an idea of my luck, I was able to sight Abell 39, confirming an earlier view; very tiny, faint galaxy KOS NP-7-22 (15th magnitude); PN's Haro 1-1, Henize 2-118, and NGC 6058; suspected seeing ESO 270-17, the "Fourcade-Figueroa Galaxy", a huge but dim object that was just setting at the beginning of the night; but I absolutely washed out on "Zwicky's Triplet": three very faint galaxies comprising Arp 103. The faintest galaxy I recorded detecting with certainty was PGC 56893 (15.8 magnitude) which suggests that I was having better than normal success on this occasion.

But unfortunately by the time I got around to northern and circumpolar objects, which I dabbled with as the sky was begin to brighten, the twilight glow prevented NGC-7635 from being impressive: it was merely discerned according to star placement and arrangement, and the very faintest sense of glow that was rapidly being swamped by scattered sunlight from over the horizon, at 4:22 am. Next time!

But that event would not have the benefit of my larger telescope, just my "cheap" 10" Orion f./4.7 Dob: on this subsequent attempt, late in the morning of Wednesday, 20 June, 2007, at the end of a very intense three and a half hours of observing faint planetary nebulae, I turned to something relaxing just before the start of astronomical twilight, and began sifting through the region of M-52 and its environs. The 8.4 magnitude star that illuminates the Bubble is only 34 arcminutes to the southwest of the brightest star in M-52; both objects may be seen in a low power eyepiece with a moderate to short focal length scope; and indeed were, in my 10" f/4.7 Dob, using my 32 mm 2" barrel Q-70 eyepiece [38x, 6.8 mm exit pupil, 112' FOV]. I added my 2" UltraBlock nebular filter, and wrote:

Sky not very dark in Cepheus/Cass, maybe a little better than 5.2 NELM. But clear, steady. Only the faintest sense of a general glow around Bubble's 8th m. *; tried UB filt. Good sense of overal neb'y. Changed to 15 mm Expanse [80x, 3.2 mm e. p., 49' FOV] and then 17 mm Highlight Pl. [71x, 3.6 mm e. p., 42' FOV] and used OIII filter: helped add a llittle more detail, glow now "striated" with 15mm and 11mm Knight-Owl [109x, 2.3 mm exit pupil, 44' FOV]. Used H-beta filt with 25mm Ultrascopic [48x, 5.3 mm e. p., 65' FOV]; finally glimpsed "bubble edge" and its brightest zone, with slightly averted vis., but no good at lower powers -- or higher ones. Of NGC-7538, only saw the vaguest regional glow around 5-6 *.

I felt that this was a pretty disappointing experience compared to earlier days, when I'd seen the object in all its glory at a very high altitude site in the Ventana wilderness, at 5,000 feet above sea level. And, my notes indicate that I stopped observing at 4:15 am, with clouds approaching San Jose and twilight's glow now becoming visible.

Three's the charm. On my very last observing session before writing this report, on the Monday-Tuesday 9/10 July 2007, I used -- again -- the 10" scope at "my site", but had the good fortune to experience more than the usual bit of summertime fog. I commenced at 10pm and spent two hours on such faint objects as galaxies NGC-4319 and NGC-4291, claiming both as well as a fugitive glimpse of Markarian 205, a quasar visible near the center of N4319, being a "speck" that is apparently visible through the southerly arm of the galaxy: objects I thought I'd NEVER see at my site, due to San Jose light pollution (you never know 'til you try!) I also achieved a confirming view of Gyulbudaghian's nebula, an obscure, faint Herbig-Haro object in Cepheus that I will be writing about eventually in these articles. With those rewarding challenges under my belt, I turned to what I hoped to be my best "non-fogged in" view of the Bubble Nebula, a bit after midnight.

But, wait! A UFO! (Not, I assure you, a "paranormal" object, nor an extraterrestrial spacecraft; just something I can't really explain.) For the second time in about a year, I beheld an unusual, anomalous sight: a very distinct, point-like speck of light, varying between 6th and 8th magnitude, s-l-o-w-l-y moving, a few arcminutes a second, through the star field near the cluster NGC-7510. The object -- whatever it was -- cycled "on" and "off", with a sustained light for 1/2 to 1 second, followed by about 8-10 seconds of invisibility; then the cycle began over again. Changing to 200x to see it better, I could discern that it went "off" rather slowly, over the course of some milliseconds of time; and for perhaps a second after it dimmed, I could just barely discern it moving, now very dull and just above the background. Then, the cycle continued. What fascinates me about this phenomenon is that it's the second time I've seen it; the first time was perhaps a year ago, at a dark sky site 250 miles south of me, near the Pacific coast. Then, the sky was so pitch-black that the light was visible by naked eye, at about 6 to 6.5 magnitude, moving diagonally (very slowly as it blinked on.. off........ on... off) across the main rectangular asterism of Pegasus, in a northeasterly direction. And now, here it was in the constellation of Cepheus, blinking at the same rate, moving slowly: and in a northeasterly direction! It did not look to me like an Iridium flare, or the ISS, or a typical satellite. Perhaps it is something tumbling very slowly, an old decomissioned satellite that has not yet degenerated out of orbit. Who knows? (I won't ask Art Bell...) Much later, I found a discussion of a similar "strobing" light seen in the sky, back in 1996, by the ardent-skeptic amateur astronomer and computer programmer Robert Shaeffer. His account seems eerily reminiscent.

After I spent a good long time soaking up this odd experience, getting over the shock of seeing it again, I turned to NGC-7635 in earnest. I wrote:

Lots of glow evident in whole region; not just light pollution. Bright halo across dimmer star of the two that frame the nebula. Tried 6mm, 7.5, 9, and 11 eypcs. Largest glow evident with SkyGlow filter and 11 mm Knight-Owl [109x, 2.3 mm exit pupil, 44' FOV], or with UltraBlock or OIII. Latter worked even with 9mm [133x, 1.9 mm e. p., 29' FOV] tho' exit pup. theoretically too small -- yet it helped! Glow is uneven, asymmetrical to S. Curves away from 8th mag *. Used AV. Looks like Jaakko's sketch. Also at some magnifications -- with 6 mm [200x, 1.3 mm e. p., 19' FOV] and 7.5 mm [160x, 1.6 mm e. p., 18' FOV] discerned a sort of "lane" in halo.

I felt relatively satisfied by this observation, knowing that unless I can move the telescope to a different location where I'm not looking toward the light from San Jose, the nebula will never look "like a photograph" -- and maybe not even then, in a pristine dark sky. It's an object to delight imagers, and to frustrate visual observers.

As soon as I got home from the mountain top, I fired up the computer and made up a very crude rendering of what I felt that I had seen, based on the rudimentary sketch (rendered in white on black) by employing a DSS image.

The 'inner curvature' of nebulosity, to the W and S of the 8th magnitude star (the one in the center of this image) was seen by me only with averted vision, when I positioned my eye just right. If I twitched, it would go away and all I could see was a generalized faint glow around the star, a little extended toward the S. The fleeting glimpse of this curvilinear feature was frustratingly infrequent and vague, compared to the way it's registered so clearly in the DSS image I used at the top of this discussion. Thinking back, as far as I can tell, I've never seen this feature very consistently. So, though I've had to "fix" it in the simulation, imagine that it would come and go...

Some other observers have had greater success with the fine details. Steve Gottlieb, who used two scopes that were both considerably larger and more efficient than mine, has contributed his findings to the NGC/IC Project:

17.5": the "Bubble Nebula" extends mainly north [center 5.5' NE] of the involved illuminating mag 8.4 star SAO 20575. There are suspected dark lanes to the north with very faint nebulosity just north of this gap. The main piece curves away from the involved star towards the east but appears brightest at the western edge near the bright star. Only a portion of the rim of the "Bubble" was viewed. The view improved with OIII and UHC filters but not dramatically. M52 lies 35' NE.

13" (9/29/84): unusual appearance - surrounds a mag 8 star with a mag 7 star nearby to the SW. The nebulosity mostly appears north of the mag 8 star with a suspected dark lane to the north of this nebulosity. Very faint nebulosity appears close north of this lane. The main section hooks around the involved star to the east.

My simulation picture, and Gottlieb's description in his 13" scope, would seem to be at odds. I show a slightly brighter curvature of glow to the W of the star, but Steve finds that "the main section hooks around the involved star to the east". What gives? Normally I would immediately conclude that I had -- as I sometimes do -- reversed my directions by accident. But, with a fixed Dob scope, it is very easy to tell which direction is to the west: the stars are slowly moving out of the field in that exact direction. I made a crude drawing in my logbook that shows my inverted optical train's rendering of the relevant bright stars, the irregular glow around SAO 20575, and where I thought the curved part was, which is inside the larger asymmetrical 'bubble'. Any my rough sketch matches what I remember seeing, and after quite a lengthy comparison process, using DSS pictures rotated and inverted to match what I thought I saw, I find quite consistent agreement. Therefore, the problem is -- I believe -- in the ambiguity of language and what individual persons perceive. What, for instance, is PRECISELY meant by "main section"?

However, in Gottlieb's later examination with his 17.5" scope, he is more explicit. "The main piece curves away from the involved star to the east...": this much is in agreement with the view he had earlier with his 13" scope. But, he continues, it "...appears brightest at the western edge near the bright star." So, the apparent contradiction is resolved. These details are very faint by eye though certainly not in a long exposure photo. When high magnification is attempted, to blow them up clearly, the nebulosity unfortunately disappears or becomes even fainter; and with small exit pupils the nebular filters no longer work effectively. So one must adjust the magnification to be sufficient to see SOME detail without losing a sense of the whole field, allowing the eye to discern fine shadings of glow in relation to the normal background values of clear space.

Steve Coe's observation, added to the Saguaro Astronomy Club website list of constellation objects for Cassiopeia, is briefer:

13" f/5.6
NGC 7635 Faint, pretty large, much elongated (5x1). A curved arc of nebulosity with some striations or other detail at 100X with the UHC filter. This is a difficult object without the filter.

Using a much smaller scope of 8" aperture, Jeff Burton notes that when seen at Pennyrile State Park in Kentucky in October of 2003:

At 91x with the 22mm eyepiece in the 203mm SCT, NGC7635 appears as an extremely faint, oval-shaped, diffuse patch of light with no discernible surface details.

(Ah, I'm doing better than an 8" scope in a dark sky site, though not as well as Gottlieb's 17-incher!)

Finally, Greg Crinklaw, developer of Skytools software, has added a marvelous web page about the object to his "Skyhoud" archive: in this discussion -- which includes an eyepiece field view -- Greg says:

Lying near the open cluster M 52, this faint nebula is a challenge for users of large and small telescopes alike. Just glimpsing any of it in six inch or smaller instruments is a bit of a feat, and larger telescopes promise to reveal intricate details...

For me, this one was tough in my six inch, even from the dark skies of the Sacramento Mountains of New Mexico....

Using averted vision I was able to briefly glimpse a very faint hazy bar between stars 1 and 2. I also had the impression of some haze to the right of the bar. I made this observation not having read any descriptions of the nebula...

In larger instruments a round glow can be seen about my star 1. At 150x or higher this glow may appear asymmetrical, splitting into distinctly separate arcs.

The Bubble bears a remarkable similarity to Thor's Helmet

[Note: that is the winter nebula NGC-2359, which I've discussed in this "Fuzzies" article. -- srw]

Here are some remarkable amateur images:

•  By Vern Raben. I was interested in this particular one, since I too own a Celestron C-11 telescope. Vern employed a Meade F3.3 focal reducer, and Astrovid Stellacam II. Not too much of the dimmer nebulosity was recorded: perhaps even slightly less than may be seen by eye with great diligence, using a nebular filter.

•  By Brad Wallis. Here's an interesting experiment: Brad Wallis's 1997 picture, a composite of 2 half hour exposures with a 12.5" f/9 Ritchey using prototype adaptive optics.

•  By Jerry Lodriguss This fabulous wide field color rendering includes also the open cluster M-52, which is easily seen (often in one's finderscope) and therefore a good reference point for finding the nebula. The large scale image was taken by means of an Astro-Physics 130EDT f/8 Triplet Apochromatic Refractor (f/6) with 0.75x matched telecompressor, in a composite of 6 frames of 10' exposure time.

•  While this next picture is by no means the "ultimate" that one can achieve, it should be included as an example of what may be a good representation of the best possible VISUAL experience with the Bubble Nebula, replicating the result I've achieved by eye with my C-11 (or, years ago, with my 17.5 inch Dobsonian): it is a CCD image done by simple means with inexpensive equipment (Meade 8" f/6.3 SCT, Alpha Mini CCD with Philips chip) by the author of the free Windows planetarium program "HNSKY", Mr. Han Kleijn.

Surely, every decent star chart and planetarium program plots the "Bubble" nebula. But in case you do not have software, I provide a Telrad chart, cropped to a field width of under 1 degree, showing the close proximity of M-52, and with prominent stars labeled with ID and magnitude. So, Lawrence Welk fans: turn ON the bubbla-machine!

Eyepiece View Chart: upright, correct

Addendum, 7/13/07: I received some further information from Jaakko Saloranta about the way the Bubble nebula looks in his 3" refractor, which was particularly interesting as his email came just a few hours after I viewed it again in my C-11, and compared that view with what I had seen 3 days earlier in my 10", writing in my logbook, "Not better with Celestron; no more detail than seen in Dob." I was rather disappointed: the object is somewhat paradoxical as the C-11 has 18% more light grasp and far better mirror coatings! One would expect quite an improvement. However, I was delighted to be able to note that my view of nearby nebula NGC-7538, about 55 arcminutes to the W and slightly N of the Bubble nebula (please refer to this Jerry Lodriguss picture), was now much better rendered than my previous viewing in the 10" Dob; I wrote that is was "nicely vis in 21 mm [113x, 2.1 mm exit pupil, 30' FOV], no filt. UBlock makes it brighter but OIII makes it seem much bigger!"

Jaakko, who lives in Finland, explains that "The Bubble nebula is in a good place for me - it is in the darkest section of the sky during the darker nights of the Fall and in zenith. And I cannot say it is particularly difficult to see with the 3" with filters. Faint, but as I remember what to expect and what to look for it is not that bad. It is just like NGC 7006 or NGC 891 - you can spot them with small apertures easily." (Links given are directly to eyepiece sketches made by Jaakko's friend Jere Kahanpää, who used an 8" scope.)

The letters A, B given in the 25-arcminute square picture of M-51 and nearby galaxies, above, are purely arbitrary and were designated that way by me merely for the purposes of identification of two extremely faint galaxies that I only recently noticed, as they were not plotted by most of my astronomy software nor shown in my atlases. The main object is of course the famous Messier 51 galaxy, the large face-on spiral that is so well known; it was given the number 85 in the Halton Arp Catalogue of Peculiar Galaxies, the first of two objects in this interacting galaxy pair, the second being NGC-5195. M-51 was possibly  the second deep-sky object I'd seen in a telescope, dating back to 1961 when I glimpsed it in a 6" Edmund Newtonian; before that, as a child in Iowa, I had found M-31 with binoculars. So, M-51 is one of the galaxies that I have observed the longest and most often, though in recent years only a few peripheral things have attracted my attention: namely, to view its rare supernovae; and to test seeing conditions and telescope resolving power. In addition, for the last few decades I have seen it constantly: every time I look at Burnham's Celestial Handbook!

The reason that the famous and bright M-51 is included in my "Faint Fuzzies" overview is due to the two faint "A" and "B" galaxies, which I consider a significant test of your perceptual skills, scope, and sky. In a discussion thread about trying to get a very distinct view of the spiral arms of M-51 in the forum Moderated Sci.Astro.Amateur (not to be confused with the unmoderated newsgroup s.a.a.) various opinions were offered about what size aperture telescope is needed to get more than an impression or averted-vision glimpse of the details of the spiral arms. I can barely see them in my C-11 or 10" scopes, despite the brightness of Messier 51. It has been held in old popular astronomy books from the fifties and sixties that "a six inch telescope" can do it. I don't find that to be the case at all; if you did not KNOW beforehand what to expect, the "arms" do not stand out with distinction at all with such an instrument. (But, oddly: the books also say that "you can't see the bridge between M-51 and NGC-5195 in anything smaller than a six inch" while I am quite sure, and satisfied, that I have indeed seen it in my 4.7 inch refractor -- yet the arms were not visible.) This exchange put me in mind of my observation of M-51 at "my site" on Sunday morning, 17 June 2007, at 1:10 am. I was using my Celestron C-11, being pointed by software running on my laptop computer. The weather that night was, as I logged earlier, "warm, clear, ground fog!, with VG seeing". Due to the reduced light pollution from San Jose, I was greatly enjoying a view of objects in the north circumpolar constellations, a rare treat at my regular observing venue.

About a half hour earlier, I had spotted more than a suggestion of the faint companion galaxy to NGC-5639 (A) in Boötes: HOLM 651B, or NGC-5639(B). According to the NED page for this obscure object, 2MASX J14285713+3024237 (using its more 'professional' modern designation) is just a tiny 'whiff' of a galaxy, with a photographic magnitude of 17.3 (!) and a diameter of 0.44 by 0.24 minutes (see it here.) So, that being detected, the sky, the night, and my eyes had been calibrated as being quite nicely tuned up for high performance!

Noticing the darker than usual sky in the region of the Big Dipper, I looked for an object to try out. My sky chart program showed M-51's prominent and large isophote, and I clicked on it, slewing the telescope around for a look. After studying what I could see of the nucleus and arms -- still not "dramatic" or particularly distinct, compared to any photograph, I noticed that onscreen were two very faint small galaxies, one whose name was almost completely obliterated by the letters for M-51's companion (this is a frequent annoyance I have with all my star chart software: the jumbling or obscuring of object IDs.) The two galaxies were IC-4277 (designated "A" in my picture, at the top of this article), with a diameter of 0.9 by 0.1 arcminutes (a thin spindle indeed!) at merely 16.5 magnitude (photographic); and IC-4278 (my "B" above), a rounder diameter of 0.5 by 0.3 minutes at 16th magnitude (also photographic): both objects had about the same surface brightness, being respectively 16.5 and 16.0 magnitude per square arcminute. 4277 would be a real challenge, considering the narrowness of its shape, and its dimness.

Did I see them? YES! I even made a sketch for later confirmation, which is included below. The galaxies in fact barely show up in the "raw" download of the POSS-1 blue plate; for the picture at the top, labelled with red designations, I had to enhance the two small galaxy images heavily since they almost disappeared when the image was shrunk down to the standard size I use in these articles. So, I have included a cropped region of the original GIF image, with the two IC galaxies highlighted with extra image contrast stretching. To appreciate how faint they are, download an original DSS plate yourself and look at it just as it comes in to your PC!

Having seen M-51 and its companion NGC-5195 so many, many times, my concentration was now focused on these 'new' IC objects. They are so obscure that the deep sky maven Steve Gottlieb has not even observed and described them for the NGC/IC Project.

Furthermore, even with a 25 inch aperture scope they don't "leap out" as can be verified by reading Kent Blackwell's remarks here (he didn't see them, and though he studied M-51 closely in fact forgot they were there, and didn't specifically look for them.) According to Wolfgang Steinicke's research, these two "little" galaxies were discovered with Lick Observatory's 36 inch Crossley telescope in 1899, photographically, by James Keeler, as shown on this page of Wolfgang's NGC/IC bios. Keeler's original announcement may be downloaded via this page. Keeler notes that he found a "pre-discovery" image on a plate taken of M-51 earlier by Isaac Roberts, but it was "confused with the strongly granular background". Keeler also looked by eye at these objects -- astronomers did that sort of thing in those days! -- and wrote that "Although these nebulae are quite conspicuous on the photographs, I found on examining them with the 36-inch refractor, that all but the brightest [IC-4263] are nearly at the limit of visibility with that instrument... In fact, this region seems to be filled with small, unconnected nebulae, large numbers of which would doubtless be revealed by long- exposure photographs." But, tragically the rising star James Keeler would pass away (from a "stroke of apoplexy" following overwork that stressed his bad heart, according to astronomer W. Wallace Campbell) at the young age of only 43, some 14 months after the Monthly Notices of the Royal Astronomical Society published his account of these discoveries, contributing 7 new objects to the Index Catalogue.

My own logbook notes the following observation:

Suspected two faint gxs with 11 mm + SkyGl filt. [255x, 1.1 mm exit pupil, ~19' FOV]; got them for sure with 9 mm + SG [294x, 1 mm exit pupil, ~10' FOV] while scanning across FOV. Even detected the position angle of 4277! It points E/W. Much larger than 4278 but is v narrow. Both V V F. Also, finally saw w/o SG. With 6 mm [466x, 0,6 mm exit pupil, ~8' FOV] could see 4278 but not 4277. So vague it was difficult. Many F *s not in the GSC visib, fainter than 15th mag. Low fog NOT covering all of San Jose light dome; NELM maybe a little better than 5th m, nearby area!

I went on that night, viewing the faint planetary nebulae Abell 39 and 46, and the smaller planetary Minkowski 1-39, plus the much brighter one NGC-6210; earlier before seeing the M-51 region, I looked at Copland's Septet, and the small, very faint, and obscure 14th magnitude galaxy NGC-4110: all in all, a great night of challenge objects fulfilled.

Looking on the public net for recorded visual observations of these two faint galaxies, I found a couple of webpages with amateur images (including this picture done by a similar C-11 but not registered as well as I saw them by eye!) and no viewing reports at all; however, I did turn up the objects in a list (in a pdf) of "Messier's Revenges" (faint and obscure things near bright Messiers), the 2007 Award contest by of the Oregon Star Party (but, no indication that anybody had seen them yet.) However, dipping into the Yahoo "amastro" group of expert observers, I quickly located a few reports by "the usual suspects" who enjoy such struggles. Chuck Dethloff of Forest Grove, Oregon posted:

I am one who has always loved an "extreme" challenge object from time to time. I find a guideline suggested to me by Mel Bartels a number of years ago helpful. That being that to be confident of an observation, several glimpses must be had within a relatively short period of time. I like to use a period of time from 15 to 30 minutes personally...

[I] have detected both IC 4278 and IC 4277 (near M51) with a 16" scope under magnitude 6.7 skies from my back yard. Both of these observations were confirmed by fellow list member Howard Banich. The latter observation caused Howard to coin a new observing phrase, "they sucked my eye right out of my head". (grin)

I like to know exactly where to look for demanding objects and to use very high power for small galaxies at the threshold of visibility. I realize that many do not want to know exactly where to look and consider doing so extremely problematic regarding expectations. I do not find that personally to be true regarding faint fuzzies as I have also failed on numerous attempts to push the envelope of a particular scope and observing site when knowing exactly where to look and what to look for. In fact, I have failed many more times than I have succeeded over the years.

Chuck Dethloff

Hello faint fuzzy addicted's there... :)

Recently I had discussion in a German forum about the indentity and - of course - visibility of the galaxy IC 4282 which is (or: some sources claim it could be) located a few arc mins E of M51 (neighboring a 7 mag star GSC 3463:284).

A mystery until this galaxy seems to be unknown to several data bases such as NED and SIMBAD and even my MegaStar shows nothing else than a MAC (MAC 1331-4710). However POSS unveils a faint glow here, so IC 4282 seems to really exist. ...USNO A2.0 involves the object as #1350-08290564 (R mag 18.0, B mag 17.6)...

...this galaxy is clearly out of reach for my 18 inch bucket. I tried several times with no success. However both other M51 IC neighbors - 4277 and IC 4278 - turned out barely visible in excellent nights.

But what's about this hard bone IC 4282? May some of the ultra large bucket owners did succeed?

Thank you and clearest skies ever ;)

Andreas Domenico

Sigh. ANOTHER challenge to think about! But, if Andrea's 18 inch "bucket" can't get that faint galaxy IC 4282, I'd be doubtful that my C-11 could do it. It is just a barely-discerned little wisp of a galaxy on the DSS plate. I'll be happy to leave an object like this for those of my gentle readers who have 15 inch or larger "buckets".

I have left the "history lesson" about M-51 for last, since most of my patient readers will probably know this information already. The spiral arms of galaxy M-51 were first detected by Lord Rosse using the gargantuan 72-inch speculum metal mirror telescope he had constructed at Birr Castle, Scotland: which became famous ever since as the "Leviathan of Parsonstown". The observation was made in 1845, and before that, since the discovery of the object by Charles Messier in 1773, the "nebula" had not been clearly discerned as it is shown in a modern image. Rosse's picture is remarkable, though stylized and somewhat unrealistic. The galaxy acquired the nickname "The Whirlpool" and was photographed first, most likely, by Dr. Isaac Roberts (as seen here in a rather poor reproduction; I've seen it in Lick Observatory's original copies of old nineteenth century astronomy publications in much better graphic resolution, back in 1989 when I was researching late nineteenth century astrophotography.) For more information about early studies of the object, consult the fascinating M-51 page at SEDS by Hartmut Frommert and Christine Kronberg.

With regard to the claims that the spiral arms can be detected in a six inch telescope: well, maybe. But not 'distinctly', and probably not without a preconception (for instance, this article has compiled some historic observations, including one by William Herschel in 1788 with one of his large telescopes: rather than stating that he saw a spiral shape, Herschel had a vague impression that the "beautiful glory of milky nebulosity" featured "here and there small interruptions that seem to [go] through the glory at a distance." Spiral arms described? I don't think this really qualifies. In fact, Admiral Smyth used his observatory's six inch telescope to view the galaxy in 1836: "The southern object is truly singular, having a bright centre surrounded with luminosity, resembling a ghost of Saturn..." was his description of the main galaxy M-51, of the "double nebula" system. No spiral arms were discerned; and Smyth was a wonderful observer. Whereas, it required the 72 inch mirror of William Parsons (Lord Rosse) to reveal what he described repeatedly, over the years, as the "spiral" shape.

I personally do NOT recall seeing the spiral arms but I do remember very well my first observation of the galaxy, with a 6 inch reflector, some 46 years before writing this article! The first time I actually began to convince myself that I could detect them was with my 10" f/5.6 telescope, after I had the primary and secondary newly recoated with enhanced materials for better than 88% standard aluminum reflectivity: this would have been sometime around 1980, I believe. Ever since then, the only telescope I've owned that could show the spiral arms UNDENIABLY and RELIABLY was my old 17.5" f/4.5 Dob.

The ambiguity of M-51's spiral form is the same kind of paradox as that presented by the "pillars" in M-16, which can show up in an amateur photograph taken by very modest means and methods, but are VERY difficult to perceive by eye with anything smaller than a large "bucket".

Finally: two other great memories of mine, regarding M-51, are the observing of the two remarkable modern supernovae, both viewed by me at "the site": first, the one in 1994 (shown in the discovery image here), and the more recent one in 2005. I was impressed by this amateur image done by an acquaintance of mine, Mr. William Phelps of Palo Alto, California; after studying that be sure to look at this amazing "APOD" article with a fabulous picture by R. Jay GaBany.

Since I found that not all star chart programs include the two faint "A" and "B" IC galaxies featured in this article, I've prepared a 1/2 degree finder chart, linked immediately below. My star chart program really messed up the information, reversing the sizes of IC 4277 and IC 4278, which I've corrected.

0.5 degree field chart: upright, correct.

• Link to Jaakko Saloranta's observations of M-51 by means of telescopes of 3 and 8" apertures, in which he says for the three inch that "The spiral structure is almost visible, but the aperture is too small for a truly good view" and that in his second drawing with the 8" scope "The spiral structure is very difficult." But in his bottom (first) drawing with the 8" scope, he recorded it well and said, "A beautiful spiral structure." That's significantly better than I have ever done!

I asked Jaakko for some comments to explain his remarkable drawings, and he replied:

It is too much photographs on my part. I cannot look at M51 without remembering the beautiful pictures I've seen of it... Of course, the spiral structure hardly is THAT easy, I usually just see a few parts here and there and then combine them all. I suppose they're in some way fairly accurate... who knows.

Now let me tell you how this thing got started. Iiro and I were bored when we visited Tenerife in 04. We had no objects to look at (ok we did but I was interested in the small aperture views of bright Messiers and northern objects such as M101 and M51. Sooo, I told Iiro that I was going to look at M51 and Iiro said he'll try it too with his 4". Now, we saw pretty much the same thing.

That's Iiro's. I don't think Iiro spent quite as much time as I trying to see the spiral structure. So, the spirals are visible even with small apertures. Of course, it helps A LOT when you know what you're supposed to see: which way the spirals go and so forth. Same goes for M101 and M33 -- the spirals are visible with the 3". Not VISIBLE in a way that you see in a photographs or you're used to seeing in large (8-10") apertures, but they're still really there. At first gaze, you probably only see the brightenings but when you do 20-30 observations of the same pattern with averted vision, while taking breaks in the middle, the structure really is there, faintly but still present.

Now if you compare the 8" sketch with the 3" sketch... that's what I mean with the "not really visible". You can see [the arms] but the spiral structure is quite difficult and a lot easier to define with larger apertures. You see the spirals but something is missing. What is missing is gained when you use large apertures under similiar conditions.

...the idea is, with the 3" the spiral structure can be seen but it is quite blurry - just like trying to see spirals from M101 under light polluted skies. You see a brightening here, a darker patch there. You see signs of spiral structure but not "spiral structure". Now if you're patient enough you can make the spirals O'Meara style - just take a lot of time with the object and from time to time the spiral structure will curve in view for a second or two in all its "glory".

Confusing...

-- Jaakko Saloranta, 5 August 2007

I think every observing session should bring at least one surprise, and preferably more than that. It makes me quite sad to read observing reports on web forums in which folks discuss viewing over and over again just the Messier objects (which they've seen many times before) rather than striking out into new territory.

Even better: have a surprise observation of a new object, and follow it up with lots of research at home. I don't exactly plan on such seredipitous events but they seem to occur almost every time I go to "the site" with my scopes, since I enjoy staking out a region of space that is in the clearest, darkest sky, and looking at objects that are nearby, moving from one to another using my star atlas as a guide to unexpected treasures.

At my last full night's session as of this writing, which occurred on Wednesday 18/Thursday 19 October 2007, I had brought my 10" Dobsonian scope and not my bigger C-11 since the humidity was high, and I feared problems with a dewed corrector plate. It takes a LOT of moisture to affect my Dobsonian (and in over two years of use, it has only once been rendered out of commission, thanks to the fog that had accumulated at a dark sky site down the California coast.) Sometimes it is much better, in the wet seasons, to seek not necessarily the darkest skies, but the highest altitude. Thus, I was looking once again at my mountaintop venue south of the silicon valley, at 3400 feet above sea level: safe from the humidity that plagued other observers who were, about this same time, trying to enjoy the Calstar party amidst all the condensation drizzling down their telescope tubes.

The main thrust of my "Faint Fuzzies" reports has been to show what one may do, under optimal sky conditions, even while observing within a few miles of 'civilization' and its night-lighting. What I see continues to amaze and impress me; and this report is no exception. For I believe I may have seen the elusive nebula Cedarblad 211, associated with the famous eruptive variable star R Aquarii. I did not realize at once that there was anything unusual about what I perceived, until I took my logbook in hand a few days later and began to investigate on the Net. Then, to my astonishment, I found that there was only ONE tentative partial observation -- a sort of inference -- by none other than the redoubtable Steve Gottlieb. And it dates back many years.

This fact naturally makes me very skeptical about the report I'm about to describe; I would hold off posting it until there is more corroborative evidence but weather has been very uncooperative this fall, and the earliest I might likely check again will be toward the middle of November (a notoriously bad time for both sky transparency and seeing in my neck of the woods.) I wouldn't blame readers for suspecting that I've made a terrible blunder. That could be. But, in the eventuality that there is any possible truth in what I thought, naively, I was seeing as a matter of course, I offer the following experience.

I was preparing for a long night to try and observe the faint planetary nebulae Abell 9 and Abell 19, for which I had created detailed finder charts; but they would not be high enough to observe for some hours. Starting in the constellation of Aquarius (to double check the color one could see in the "Saturn Nebula", NGC-7009) I spent a long period of time studying the bright planetary, definitely not a challenge object and one that perhaps does not warrant an article here, since it is at least detectable in the smallest instruments (I've written a report of what I saw in my astro-blog); then I moved a little less than 3 degrees to the southwest to the famous globular cluster M-72 (which I described as having "two br *s to the E, gc dim, not resolved but with 3.5 mm eypc [341x] sensed 'grain'; poorer with 2.5 mm [478x].")

By now it was 11:30 pm, and I had two or more hours to "kill" while waiting for Abell 9 to rise above the heavy air at the eastern horizon. Having spent hours during the afternoon reading about, and preparing to observe, the two faint and incredibly difficult Abell planetaries, I had not done much of any other cogitation about my night on the mountain. What to do now? I made a fitful attempt to determine the naked eye limiting magnitude in the region of Skat (Delta Aquarius) and concluded that it was about 6th magnitude in that direction: not bad for a night with very little ground fog below the mountain range. I happened to notice a little square icon for "Ced 211" on p. 76 of my Sky & Telescope Pocket Atlas, listing an object with which I was unfamiliar, apparently associated with the star marked "R". Since I am not a variable star observer, this fact made absolutely no impact on me, never having tried to determine the brightness of R Aquarii, which -- as I learned subsequently at home, right after the observing session and before sunrise -- was extremely famous. It is, in fact, described as 'the variable star of the summer season' on the website of the American Association of Variable Star Observers. It was early October and a little late to be studying R Aquarii; but I was interested in this obscure "Ced 211", and looked it up in the index of the Uranometria atlas, opening page 121. I noticed the star was about 48 minutes due west of a faint galaxy, IC-1509; at least if I missed the Cederblad nebula, I could enjoy looking for yet another indistinct, dim, and difficult object from the Index Catalogue!

But first, Ced 211. I turned my scope onto the field and triangulated from the bright star 105-Omega2 Aquarii (SAO 165842, magnitude 4.6), which was very evident to my naked eye, and brilliant in my finderscope. Ced 211 would be 47 minutes to the SSE; taking great care to keep SAO 165841 (5.4 magnitude) out of my eyepiece field, I maneuvered onto dimmer HD 222800 (SAO 165849), the variable. These particulars became known to me specifically not at the time, but later: when I used my star chart software to re-create my perigrinations. The Uranometria of course does not identify most of these stars and only has the most general binning of magnitudes; and R Aquarii was indicated by a little unfilled circle. I really had no idea how bright it might be.

Well: what I saw WAS indeed a brightish star, somewhat dimmer than SAO 165841. Cranking up the magnification, I inserted my 6 mm Expanse ocular [200x, 1.3 mm exit pupil, 15' FOV] and looked for signs of an obvious nebula (which the Uranometria Field Guide identified as "E" -- for emission type -- but with no brightness indication: only the size of 2x1 arcminutes.) I did seem to notice something 'around' the star, and was surprised that its shape and larger axis changed, depending on whether or not a filter was employed:

"6 mm: faint oval halo around R Aqr. Best in 6, no F. Tried U'Block, H-beta, OIII - various mags. Not very evident improvement in UB or SkyGl; H-beta: nothing seen but *, even with 25 mm @ 48x. Using 6 mm W/o F, more to NE. But with SkyGl F, more neb'y to W. Star seems harder to focus sharply than others nearby: slightly fuzzy"

I made a very rough sketch in my logbook (noting that the 'double star' was further away to the NW than shown in the drawing, out of the field of view) and then went back to the scope and looked again, using my 5 mm and 3.5 mm eyepieces (both very similar types, being specifically an Orion Stratus and a Baader Hyperion.)

"5 mm [240x, 1.1 mm exit pupil, 17' FOV]: glow on W side, plus general vf halo with UB, even OIII. Other vf *s seen."

It would appear that at higher magnifications of 240x and 341x, with oculars that had much better transmission that Expanse 6, the nebulosity that I could see, to the west of the star R Aquarii, was a small narrow extension that was perhaps -- judging from the 12' field of view of the 3.5 mm eyepiece, only partially shown in my drawing -- perhaps an arcminute or less in length.

I also noted that "star is very red, w/9mm [133x], 3.5 mm [341x], or even 25 mm [48x] -- though not as red with 15 mm Expanse [80x]." (I had wondered about my 15 mm Orion Expanse eyepiece, finding it not to be a very good one. Perhaps its color and intensity transmission leave something to be desired.)

Looking at the color image by David Malin, obtained with the Anglo-Australian telescope, one can verify that the star registers with a strong yellow-orange hue on the tri-color composite film process. The star is actually a binary system, a red giant and a smaller blue companion; it is a "Mira-type" variable (a red star which pulsates with large magnitude variations.) According to this AAVSO article:

The variability of [R Aquarii] was first seen in the early 1800s by Karl Ludwig Harding (1765-1834). Harding, an assistant at the Johann Schoter's [sic -- Johann Schroeter's] Observatory in Lilienthal, Germany, was originally looking for a "missing" planet between Mars and Jupiter as part of the "Celestial Police" project at the observatory... what makes R Aqr so interesting is the assorted components that make up R Aqr system and the light curve that follows... Classed as a symbiotic variable and situated at a distance about 650 light-years (Robinson 1988), R Aqr is the closest star of its type to Earth.

R Aqr was originally considered to be a "regular" long-period variable until the early 1900s. In October of 1919, a slit spectrogram of R Aqr taken at Mount Wilson Observatory showed several emission lines revealing a hot gaseous nebula... known as Cederblad 211, [it] was seen in 1921 on photographic plates taken at Lowell Observatory by Carl Lampland...

In 1939, Edwin Hubble detected the expansion of the nebula and subsequent measurements of photographic plates by Walter Baade confirmed Hubble's finding. The nebulosity of R Aqr is, in fact, comprised of two distinct sections of seemingly ghostly matter: an outer region of about 2 arc minutes and an inner one of about 1 arc minute (Robinson 1988). Assuming a rate of constant expansion, it is theorized that the components of the nebula were formed 640 and 185 years ago, respectively and may be the result of a nova-like event (Robinson 1988).

Variable star observers -- of which I am definitely not a practitioner! -- are particularly interested in R Aquarii; according to the AAVSO, there are more than 16,000 observations in their database. The star's widest magnitude range is from about 5.8 to 12.4 magnitude (its light curve may be seen here); since the object's brightest maximum, over a 387 day period, was at the close of October in 2006, it was (at the time of my observation on Oct. 17, '07) once again nearing the maximum again.

According to an article about objects in Aquarius by P. Clay Sherrod, the nebula resembles, in some pictures such as this one by Lick Observatory, a bat's wings in flight. Sherrod calls it "the bat nebula" (not to be confused with the more familiar use of the nickname, for IC-2948 in Centaurus, an object that I'm sorry that I'll never be able to see from northern California! Please note also that there is another and even more obscure reference to the nickname: the 'flying bat' nebula -- Sh 2-129 -- in Cygnus. And, note also that Sherrod refers to "the 100" Lick Observatory reflector": a mistake, as the observatory has no instrument between the size of the 40-inch Nickel telescope, and the 120 inch Shane.)

When I went to the Net in order to find corroboration of my alleged sighting of the nebula, only two discussions turned up amidst the plethora of posts and web pages about R Aquarii: an IAAC report by Steve Gottlieb, dating back to 2001, and a brief thread from 1999 in the Yahoo group, amastro. Gottlieb says this of his "inferred" sighting with a 17.5 inch scope in September of 1998:

This is a very faint nebula surrounding R Aquarii (m 5.8-12.4), a unique long-period variable (interacting binary consisting of a red giant and a white dwarf). Surprisingly, at 100x and 140x no nebulosity was visible; but the illuminating star, 10th magnitude R Aqr, showed a mild contrast gain with both UHC and OIII blinking. A very similar comparison star, mag10 GSC6404-0860 is 14' NW: this star loses 2+ mags with filtration, while R appears of very similar brightness with the filter, or possibly slightly brighter. At 220x, no nebulosity seen with confidence, but once or twice I suspected a short extension to the NE.

In the amastro discussion, both Steve Coe and Jay LeBlanc reported negative results in their 1999 attempts to see the nebula; Gottlieb said, "I didn't make a definite sighting of nebulosity, but I did record a filter response to R Aqr". So to summarize his 1998 report: he too can't claim that the nebula was distinctly discerned.

The Saguaro Astronomy Club database includes Ced 211, but Steve Coe -- who has contributed hundreds of observations to the club website -- does not mention Ced 211 in his page for objects in Aquarius.

But, as Sherrod notes, "The light curve shown following demonstrates that this star is ANYTHING but predictable" though he also states that this "huge cloud of gas and dust [is] a shell that can be photographed, but not seen". I am always skeptical of such statements, especially since the nebula is not THAT hard to find on the DSS images, requiring not particularly extreme processing to bring out sharp detail.

As you can see from the work I've done on the second survey plates, above, the red-sensitive picture at right has brighter nebulosity -- especially the vivid central halo of glow around reddish R Aquarii -- plus denser knots toward the east and west; but the glows show up on the blue-sensitive picture too (which seems to have denser nebulosity immediately south of the star system.) Yet, I've found that some faint planetary nebulae that can be seen distinctly in a telescopic view, often barely register at all on the blue plate of a DSS pair.

When the Hubble Telescope was new, even before the modified image corrector that sharpened the image from the deficient primary mirror, R Aquarii's nebulosity was imaged. In 1990 this picture was released, which one commentator explained as having an overexposed (dark black) central region due to the bright light of the stellar components of R Aquarii. What sharpening that could be done was achieved by deconvolution software. I have taken that picture and rendered an 'artist's version', attempting to restore the bright central brilliance of R Aquarii's two red and blue components, shown at left.

I assume that the orientation of this image is NOT north pole up, as it seems to differ so much from the Lick Observatory and Palomar Survey pictures.

You won't find much information if you search the Net for "Cederblad 211". I made inquiries of the original catalogue, via the VizieR website, and determined only that the entry 211 refers to R Aquarii; the notes specify three papers (by Lampland and Lundmark) published up to the date of the original catalogue's release, 1946. Carl Lampland's two articles are quite brief; Knut Lundmark's paper (in Swedish) does not appear to be available by means of the NASA ADS service. More information about Lampland's discovery is found in this 1998 paper: The R Aquarii Jet in Hindsight, by Hollis, Bertram, Wagner, and Lampland (which includes posthumous data and citations of the deceased Lampland's work; he died in 1951.) The paper notes that an increasing "NE-SW elongation" of the nebula was evident in comparing 1922, 1934, 1946, and 1988 plates made with Lowell's 42 inch f/5.2 reflector.

In the 1980 PSAP paper "The spectrum of the nebulosity around the symbiotic long-period variable, R Aquarii" by George Wallerstein and Jesse Greenstein, the nebulosity is described as being filamentary in character, as registered on Lampland's photograph, with an elliptical ring. Radio continuum emission, which is significantly polarized, was detected in 1974; it is caused by an SiO maser, with an output at 85 GHz. The authors state that "The extended nebulosity is expanding, and is not changed much in appearance in over 50 years." Their study of the nebula was done with R Aquarii at minimum magnitude, permitting measurment of the spectra of the gaseous environment but not the variable star. Thus, if it were possible to see the nebula, its brightness does not necessarily coincide with the vividness of R Aquarii.

I had a great deal of difficulty in matching my drawing of what I'd perceived, against star chart software. Unfortunately I had not provided quite enough field stars for easy results. In my top drawing, done with the 6 mm Expanse eyepiece, I show that the apparent double star indicated at the upper left corner is out of the field of view. That would seem to be an optical (not actual physical binary) pair of stars, SAO 165837 (10.36 magnitude) and GSC 5836:200 (12.1), with a separation of 3'38", found about 32' to the NW of R Aquarii. Therefore, my drawings are oriented so that west is in the direction of this "double", with north found 90 degrees counter-clockwise to the left. That's the way my sketch was originally labelled, but after scanning it and looking at other references, I changed my mind several times, wondering if I had erred. My final conclusion about direction is based on this "screen dump" made by means of the software program TheSky VI, with the polar rotation tool adjusted to try to match my drawing.

However, it's hard to match the stars shown in my lower sketch with the 3.5 mm eyepiece to the screen capture of the star chart program, which is limited to the Hubble Guidestar catalogue. I also checked with the USNO 2.0 plot generated by the Deep Sky Browser page for the object, and after inverting and turning the image around for a long period of time, finally gave up in confusion, as I seem to have sketched some extremely faint stars that aren't plotted. I should have recorded more bright, obvious stars for reference purpose!

The "smoking gun" would seem to be that optical 'pair', which stands out when you get a plot of the area. But, again, I've left an unsatisfactory record of what I believe I truly saw: the brighter member is registered stronger than the "speck" in the middle of the R Aquarii complex. Is this because of my difficulty in focusing the latter (as I noted); or an actual blunder? Part of the problem is that I drew the charts at my table, about fifteen feet away from the scope, rather than with the paper beside me at the eyepiece.

So, much more work is needed for me to find this observation entirely reliable. While there SEEMED to be a nebular phenomenon present, I believe it would be prudent to take the course of Gottlieb and -- contrary to the rather messy 'data' I've given to document the experience -- not assert that I saw Cederblad 211 with absolute certainty. It's up in the air, and if circumstances cooperate, I will try again before the star is too low for success, or -- at the very least -- check again next season.

To make yourself a finder chart for R Aquarii, use this webpage on the AAVSO site, where you may download a highly detailed GIF file that may be reduced for printing.

Update: CONFIRMATION!  I have made two subsequent attempts to observe R Aquarii to try to catch sight of its strange nebula. On 5 August '07 I was unsuccessful; the object was too low and into murky air, which reduced clarity somewhat. Other than a vague glow that I seemed to see to the N of the star, nothing showed up that seemed directly comparable to the pictures. But, on the night of Wednesday 7 October I tried earlier in the evening, at 10:30 pm, and had definite success! My notes state: "seeing vg, clear. 3.5 mm epc [341x, 12' FOV]: Airy disk vis around *, 2-3 rings, consistent and broken only occasionally. Added SkyG filter. At steadiest moments could see fuzzy patch with faint narrow striations much longer/wider than Airy disk. One long streak runs W-E. Saw several times momentary views of a clear 'terminus' like a little sharp speck on the E side. Changed to 5 mm epc [240x, 17' FOV]: ditto! Smaller view but similar aspect. Added U'Block filter -- much smaller neb but could see 'spikes' and streak when seeing v. steady!" My sketch here is a pretty good representation of the best views of this phenomenon (which reminded me of the ansae of the "Saturn" planetary nebula NGC-7009, which may be seen here clearly in this exquisite digital image by Daniel Verschatse.)

The lenticular galaxy NGC-1023 is large (8.7' x 3') and is rated at about 9.5 visual magnitude, with a moderate surface brightness of 12.9: thus, it's considerably brighter than NGC-891, which many observers seem to have trouble finding unless they are working in a very dark sky (at my site, N891 can be seen in a 4" scope.) N1023 was discovered in that fateful year 1786, when William Herschel used his metal mirror telescope (18.7 inches aperture) to sweep up hundreds of such objects, assigning this 'new nebula' the number 156. There is no clue from the original Herschel publication of 1789 (a 15 megabyte PDF file available here) that he saw the faint companion galaxy; the master observer recorded only that -- translating his abbreviations -- the object was "extremely bright, much extended", with references to specific marker stars. Nor is there any indication in the original version of Dr. Dreyer's New General Catalogue, which does not include the companion, describing NGC-1023 only as "very bright, very large, very much extended, very much brightening in the middle".

Globular clusters in NGC 1023 are visible to the Hubble Space Telescope, and have been studied by Søren Larsen and Jean Brodie of Lick Observatory, as reported in the paper "Hubble Space Telescope Observations of Star Clusters in NGC 1023: Evidence for Three Cluster Populations?" (finding that of 221 candidates there is a "bimodal color distribution" with some of them having predominantly red or blue stars.) I was very amused to note that the professional astronomers Michael Fellhauer and Pavel Kroupa of the University of Kiel refer to these globular clusters in a scholarly paper ("The Spatial Distribution of Faint Fuzzy Star Clusters in NGC 5195") as 'faint fuzzies': surely fainter -- at 23rd magnitude -- than any objects I can detect with my 10 or 11 inch scopes!

The companion galaxy, comparative 'tiny' NGC 1023A -- shown above in the POSS picture as a faint oval smudge on the eastern side (to the left) of the halo of NGC 1023 -- possibly has a central bar (as does its larger partner; the DSS images do not show these details with clarity.) After a cursory Net search I was unable to determine the discoverer of this faint (14.5B) and small ( 1.3' x 0.7') galaxy. A succinct summary of the progression of understanding of the object is given in a 1979 paper by N. J. Allsopp: "NGC 1023 is illustrated in Arp's (1966) Atlas of Peculiar Galaxies as No. 135; it was included because of a remarkable cloud-like extension at the eastern end of the major axis. From a colour analysis, Derevjanko (1971) concluded that this cloud has not been ejected from NGC 1023 and Barbon and Capaccioli (1975) suggest that it is probably a dwarf companion." According to a 2002 paper by Tikhonov and Galazoutdinova1, "definite existence of the physical NGC 1023 group, consisting of five galaxies, was first indicated by Humason, Mayall, and Sandage".

The faint "cloud-like" companion was given the designation "A" in a paper by Barbon & Capaccioli (1975): a very deep photo, processed to show isophote contours, may be seen here. NGC 1023A is clearly visible on the left, to the east of the nucleus of NGC 1023. One of the earliest post-NGC references I found was a 1917 paper by Francis Pease, discussing photographs of "nebulae" made by the 60-inch reflector at Mt. Wilson, and citing recent spectral measurements by Fath and Slipher.

The "NGC 1023 group" consists of a number of significant galaxies, including NGC 891, NGC 925, NGC 1058 (whose recent 2007 supernova I observed and sketched, described here), and NGC 1239. In addition there are a number of dwarf galaxies -- perhaps as many as seven -- of which four are noted in a 1984 paper by Davies & Kinman. The only one I've seen so far is NGC 1023A, though "NGC 1023B" -- PGC 10169, 17p magnitude (discovered on a plate made by James Keeler in 1899 with the Crossley telescope) -- might be visible under certain circumstances with my 11" SCT, and surely could be detected in a large Dobsonian telescope.

A progression of what might be seen, optimally, by a very skilled observer using increasing aperture sizes may be inferred from these three reports by Steve Gottlieb:

8" (11/8/80): fairly bright, bulging bright core, lens-shape.

13" (12/24/84): very bright, impressive, elongated ~E-W, bright core, stellar nucleus.

18" (8/1/05): at 225x, this striking galaxy appeared very bright, large, very elongated 4:1 E-W, ~4.5'x1.0', though can possibly be traced further with averted vision. Dramatic, sharp concentration with an unusually bright, oval core. Two mag 14 and 15 stars are superimposed off the west side of the core and a mag 14 star is off the east side. 17.5" (12/8/90): bright, large, very elongated 7:2 E-W, very bright core, almost stellar nucleus. A large fainter halo increases the dimensions to 7'x2'. Two 15th magnitude stars are superimposed on the east and west ends. 13" (12/24/84): very bright, impressive, elongated ~E-W, bright core, stellar nucleus.

   - by Steve Gottlieb    [found in this text file at the NGC/IC Project website]

While I did not include NGC-1023 in my "Eyepiece" program database of galaxies, specifying objects in John Sanford's book OBSERVING THE CONSTELLATIONS, most of which I observed in the late 80s and early 90s, I do have a vague recollection of looking at it years ago, though no notes survive. So on the morning of 14 November 2007, I came upon it with few preconceptions except only the remarks I'd read the day before in Tom Trusock's very useful overview of objects in Perseus, in his "Small Wonders" series. However, Tom does NOT note the faint companion "A", saying only:

Dropping 3 and 2/3 degrees almost directly south of M34, we run into the brightest galaxy in Perseus, NGC 1023. This bright galaxy is classed SBO, which means it's a spiral with a central bulge, but no arms. Recent analysis done using the HST and various ground based telescopes has shown evidinence of a super mas