NGC6926

Galaxy hunting in Aquila is about like hunting polar bear in the Antarctic. Unlike Antarctic polar bears or arctic penguins, there are a few galaxies in Aquila worth looking at if you look long and hard enough to find them. NGC 6926 is one such galaxy. It is a huge rather disrupted spiral galaxy some 150,000 light years tall if you count the short plume to the north and 130,000 if you don't. Either way, it is a very large spiral. Its northern arm is drawn out and has two major star clouds in it. The southern is so disrupted it has a hole in the middle of it. It is part of a group of galaxies. Two others in the group are in my image, NGC 6929, a peculiar SA0+ galaxy to its east and UGC 11585 in the southwest corner of my image which is also listed as a peculiar galaxy. The status of NGC 6929 as peculiar is a bit questionable as indicated by the colon in the "pec:" designation. UGC 11585, however, has no question about its peculiarity. Like NGC 6929 it has an apparent hole in its disk. It looks like I overprocessed it so the field star developed the dreaded "Panda Eye" dark circle. But the dark area is real. An ordinary looking edge on dwarf disk galaxy, 6dF J2032205-020828 may also be a member of the group.

NGC 2926 was discovered by William Herschel on July 21, 1784. It isn't in either H400 program. NGC 2629 was found by John Herschel on July 21, 1827.

There's a trio of galaxies at the bottom center of the image that are all about 720 million light-years away which may be part of another galaxy group.

A distant member of the group, NGC 6922, lies far west out of my image. It too is peculiar. It's quite unusual to have a group so full of galaxies carrying the peculiar designation. Due to weather, I was unable to capture NGC 2922 this year. Maybe next year. (Edit: It has now in my collection.)

The field seems to have some faint nebulosity in it. I see a hint of it in the blue POSS 1 plate so think it real. I had a light leak in my system that started with the previous image at the end of July. I didn't look at the images until August 8 when I found it was there and fixed it. I don't think it the cause of the faint glow as it caused other issues. Unfortunately, I took 6 objects before realizing it was there. None show this glow, however. another reason to think it real. Thus I left it in.

The field is little studied being deep in the Zone of Avoidance. Thus the annotated image has only the galaxies mentioned above as none of the many others in the image has much info at NED. Most aren't even listed there, only those few that were strong IR sources to make the 2 micron sky survey are listed. Since they are identified by position only I didn't include them.

For a change I had normal transparency but seeing was running nearly 4". I applied a lot of deconvolution to get it down to near 3". Far more than I like to use. Still, for this year it's a good image, as conditions have been so poor.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for NGC6926

NGC6928

NGC 6928/2MFGC 15597 is a flat galaxy in the tail of Delphinus, about 190 to 200 million light-years distant. It anchors a small group of galaxies known as the NGC 6928 group. It makes the 2 micron flat galaxy catalog but not the more demanding Flat Galaxy Catalog. Probably not being seen edge on, determining if it meets those more stringent requirements is impossible. In my image I get the distinct impression the core is depressed, that is thinner than the dust lanes in front of it as if hiding behind them. If real it likely would appear very thin and without a core seen edge on. It was discovered by Albert Marth on August 15, 1863. Then on September 23, 1888 Lewis Swift found it. His discovery became IC 1325.

NGC 6930 to the southeast is another member at the same distance. It has a very close companion that too made the 2 Micron Flat Galaxy Catalog. How I can't fathom. It doesn't appear flat to me and is classed as a compact spiral though I see no spiral structure. It does have some interesting dust and seems distorted. Could it be interaction with NGC 6930? If so I found nothing in the literature on it. It does have an AGN in its core meaning its black hole is well fed. This could, but doesn't have to, mean it is interacting. Though NGC 6930 seems pretty undisturbed by the whole affair though it appears its northern end may be hiding behind this little galaxy. There's a star just east of its core making it hard to decipher what's going on. Albert Marth and Lewis Swift repeated their NGC 6828 duplication efforts finding this one the same nights. Swift's duplicate became IC 1326.

The third NGC galaxy in the image is the mostly featureless NGC 6927 also at the same redshift as the first three. It lies to the west-southwest of NGC 6928. Below it is NGC 6927A. A companion maybe but certainly doesn't appear to be interacting. Its redshift is the only one of the group that is even slightly different putting it about 190 million light-years distant rather than 200 million like the others. It is also the smallest. Albert Marth found NGC 6927 the same night as the other two but this time Swift didn't duplicate his efforts.

Several other galaxies are nearby such as the one directly below NGC 6928 that is unlabeled on the annotated image. It's not labeled because it isn't even listed in NED. Southeast of NGC 6930 is the 2MASS galaxy 2MASX J20330454+0951338 which is just its J2000 coordinates. This means it is pouring out a lot of deep infrared light but nothing else is known at NED, not even a magnitude. It appears to be a tight spiral to my eye but again NED doesn't attempt to classify it. Most of the faint galaxies in the image are not in NED but for a handful of IR rich galaxies that made the 2 Micron catalog. The only one with redshift data is another from the 2 Micron Flat galaxy catalog, 2MFGC 15581 in the upper right corner of my image. It doesn't appear all that flat to me but it made the cut. NPM1G +09.0506 to the southeast is also in the 2 MASS catalog but also made the Link Northern Proper Motion program so tired of long 2MASS names I used the NPM1G entry instead but it too is strong in IR light.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for NGC6928

NGC6934

NGC 6934 is a rather distant globular cluster in Delphinus about 50,000 light-years from us and 42,000 light-years from the core of the galaxy so it is near the edge if the old 100,000 light-year diameter is used. A drizzle of stars have been detected further out making its diameter about 200,000 light-years but if viewed from afar that faint halo would be hard to detect. Many galaxies would appear much larger in super deep images like what would be needed to show our extended disk. So for most purposes, the older diameter seems reasonable though maybe 125,000 would be a better estimate. Hard to tell from the inside looking out.

It was discovered by William Herschel on September 24, 1785. It is in the original H400 program. My entry with my 10" f/t at 180 to 300 power on a good night reads, "Medium-sized globular with a suddenly bright inner core. Surrounded by a large but very faint halo. Inner core looks grainy but no clear resolution even at 300x. No resolution at all to the outer halo." This lack of resolution to the edge is odd as usually if a globular is grainy in the center the edges show a few stars. Not this one it would appear.

Thanks to the power of a CCD it can be easily resolved from the outer edge to the very core. As I remember my film image of this one the core was an overexposed blob but the edges showed some stars. The CCD blows film images of this one away. At least for me.

The night was much better than normal when this was taken allowing me to take and display this one at my full resolution of 0.5" per pixel. A very rare occurrence. Unfortunately, it is getting even rarer as the weather here is slowly getting worse. Global warming to blame or just a long-term trend that will reverse if I live long enough?

14" LX200R @ f/10, L=4x10'x1, RGB=2x10'x2, STL-11000XM, Paramount ME

Related Designations for NGC6934

NGC6939

NGC 6939 is a rather well known open cluster in Cepheus near the more famous NGC 6946 galaxy. In small scopes where only the brighter stars are seen they seem to array in rows much like a bank of stadium lights. That effect is totally missing from my image. The WEBDA cluster database puts its distance at about 3850 light-years though I've seen other uncredited estimates of 5800 light-years. Again, astronomy hasn't yet found a good way to pin down the distance to most such clusters leading to various estimates depending on methods used and assumptions made about extinction from dust and gas in our galaxy which is also hard to determine.

NGC 6939 was discovered by William Herschel on September 9, 1798. It is in the original H400 observing program. My entry on May 21, 1985 at up to 120x with my 10" f/5 on a good night reads, "Medium sized triangular cluster whose brighter stars seem to be arranged in rows both horizontally and vertically sot of like a square grid cut into a triangular shape. Many fainter stars are seen under this grid. My magnitude limit was about 15 this night so it was a grand sight." Later another amateur said it reminded him of a bank of stadium lights.

Sometimes you get a surprise in an image. That certainly is the case here. The field is full of dusty nebulosity. If I'd have known it was there I'd have put far more time into the image. But it came as a complete surprise when I started to process the image. At the time I processed my image of the galaxy NGC 6946 (Arp 29) I saw some of this nebulosity but thinking it noise processed most of it out. Oops. I need to be more trusting of my data. Still, hints of it can be seen in the image, especially just west (right) of the galaxy and toward the west-southwest of the galaxy in my image.

Apparently, most imaging this cluster have the same problem I did with the galaxy and thought the nebulosity was noise. It is either processed out or not seen in most images I found on the net. Only a couple showed the nebulosity. It apparently is mostly due to fluorescence from UV stars illuminating the carbon compounds in it as well as reflecting light of these very hot blue stars though one image in H alpha light showed a general glow in the area. I found no catalog entry for this nebulosity at Simbad.

If you look closely you will see many faint, small galaxies in the image some well inside the cluster. Only one in the image has a redshift value. Several others are just outside the frame. All are faint smudges and are listed at about the same redshift as NGC 6946. They are likely gravitationally bound to it. The one in my image with redshift data is LEDA 166196. It is at the top at pixel 1001x130. It is hiding behind a very orange star. It is a round reddish ball about 55 seconds of arc (55 pixels) across. A much more obvious galaxy is below it, 2MASX J20313354+6047414. It has no redshift data same as all the others in the image. Only 2 others are identified in the image. I won't try to point them out.

I need to redo this field with much more exposure time to better pull the nebulosity out of the sky glow.

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for NGC6939

NGC6940

NGC 6940 is a large type III2m open cluster in Vulpecula. It was discovered by William Herschel on July 17k 1784. It is in the original H400 observing program. My log for May 20, 185 on a good night with my 10" f/5 says, "Long one of my 'showpiece' open clusters for the public. It resembles more a star cloud than a cluster. It contains hundreds of medium to faint stars in a field filling cloud. For once the H400 guide understates the apparent number of stars in an open cluster." The "showpiece" appearance in my 10" scope is lost in my CCD image which doesn't show star brightness over the range the eye sees when looking at the cluster as it sees stars much fainter than the eye does. This image, at least the way I processed it fails to capture what the eye sees at the eyepiece of a 10" scope on a good night.

The cluster is thought to be over 700 million years old. Old enough that the bright blue stars have long since died leaving the cooler and dimmer stars to dominate. This age may be why it looks much like a star cloud than a vibrant open cluster. It is reddened only by .2 magnitudes so star colors are close to correct. Its distance is estimated to be about 2,500 light-years making it a rather nearby cluster. This was one of my very first color images from 2006. While I have the original data on backups hard to get to as one is 22 miles away in a safe deposit box, I have no exposure data easily available. I didn't keep very good records back then. I suspect the main reason this one doesn't look like its visual impression is I severely underexposed it preventing me from showing it as it really is. Also, my image processing skills were hampered by 8 bit programs and severe ignorance of how to use the limited tools I had. I really need to retake this one.

14" LX200R @ f/10, exposure data unknown, STL-11000XM, Paramount ME

Related Designations for NGC6940

NGC6951

NGC 6951 is a nice spiral galaxy seen through a veil of galactic cirrus often called IFN for integrated flux nebula. It is dust out of the plane of our galaxy being illuminated and caused to glow by the integrated light of our galaxy rather than one star it is lit by billions of stars. It is very faint and wasn't all that well known until recently. While a few brighter patches carry common names, usually for what they look like, most is unnamed as is the case with the IFN haze across this image of NGC 6951. Many images of it either didn't catch the IFN or it was processed out. I almost did the latter thinking bad flats were to blame until I found a few images showing the IFN. My exposure time is way too short to show it very well, unfortunately

NGC 6951 also known as NGC 6952. It is located in western Cepheus. Redshift puts it at 58 million light-years away but non-redshift measurements say 75 million light-years. Various sources site one or the other but I can't find any better distance for it. It was discovered by Jérôme Coggia in 1877, actual date unknown. That resulted in the NGC 6952 entry. Then NGC 6851 was discovered by Lewis Swift a year later. Again no precise date is known.

It is classified as SAB(rs)bc; LINER Sy2. Being a nearby Seyfert 2 core galaxy it is much studied. Though none seem to find the two straight dust lanes leading to the "top" and "bottom" of the core odd. Usually, the dust lanes down the bar of a barred galaxy are in the center of the bar and go directly in toward the center of the core not tangent to it as these are. I only know of one other galaxy with this type bar structure, NGC 1097. It is at 30 degrees south declination so I can't image it. Just that I see the dust lanes in the POSS I blue plate. They appear much weaker than in NGC 6951.

The image is a reprocessed version from 2008 data starting with the 16 bit TIFF file as the raw data is on drives in the fire safe in the basement or safe deposit box and not easily available. I really need to start from scratch to better bring out the IFN.

14" LX200R @ f/10, L=4x10 RGB=2x10', STL-11000XM, Paramount ME

Related Designations for NGC6951

NGC6956

LDCE 1416/KTG 71 is a triple galaxy system about 200 million light-years distant located in central Delphinus. The three members are NGC 6956/UGC 11619, UGC 11620 and UGC 11623.

NGC 6956 was discovered by William Herschel on October 19, 1784 though it isn't in either Herschel 400 observing list. It is classified as SBb. It's two arms are quite unsymmetrical. It appears to have many star clusters along is arms. It is quite large at about 90,000 light-years in diameter.

UGC 11620 is classified as Sb. It appears to be a red spiral indicating star formation has mostly ended for this galaxy. UGC 11623 is classified as SB(r)a. All have redshift values that indicate these are the same distance and thus a related group.

The field is in the Zone of Avoidance" so poorly studied. All objects NED lists as galaxies are shown in the annotated image. Obviously, there are many more galaxies in the image. Some of these are listed as UvS objects (Ultraviolet sources) rather than galaxies. The position of these is approximate. Most NED lists are just stars. Within a 20 minute radius of NGC 6956 NED lists over 1000 UvS objects. I didn't bother to annotate those that are galaxies. Sorting out stars from galaxies would take many hours I don't have to spare.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for NGC6956

NGC6960

NGC 6960 is part of the Cygnus Loop. The loop is a shock wave created by a supernova thousands of years ago. For such a well-known object you'd think we'd have a good idea of its age, size, and distance. Maybe we do or maybe not. When I first got into astronomy in the early 1950s it was thought to be some 100,000 years old. Over the years it has gotten younger and younger. Latest estimates put its age at only 8,000 to 10,000 years. As it got younger it got smaller. It was thought to be over 1000 light-years across when I first read about it over 60 years ago. Now it is down to 90 light-years across. Maybe we should call it the incredibly shrinking nebula. With the reduction in size and age, it has gotten closer and closer. The latest distance I found was just under 1500 light-years.

None of this detracts from its beauty. As the shockwave travels through space it creates a huge bubble now estimated at about 90 light-years in size. The shockwave ionizes hydrogen and oxygen gas causing it to emit light where its density and the energy of the shockwave is sufficient. Hydrogen is responsible for the red and a portion of the blue. Most of the blue (more cyan) is due to the Hydrogen. Thus in visible light, we see only parts of the bubble as portions are too thin or not getting enough energy to emit light. The western edge is NGC 6960, only part of which fit in my frame. This portion is sometimes called "The Witch's Broom". It was discovered by William Herschel on September 7, 1784. It is in the second H400 program. The entire bubble is over 3 degrees across and carries many NGC numbers or other names. Some small detached pieces have no catalog entries that I could find. One of which I simply labeled "Veil_Segment" as I found no name for it.

This was one of my very first color images and it shows. Neither my technique nor processing was very good back then. Compare this to my NGC6995 entry taken and processed years later. Most images you will find of the various pieces of this supernova remnant are taken using filters that isolate hydrogen and oxygen emission lines. I didn't do that as this one is so "bright" it isn't necessary. Also, narrowband imaging pretty well ignores background galaxies. While few are seen in this segment other, like the NGC6995 image show several missed by the typical image of this bubble.

14" LX200R @ f/10, L=4x10' RGB=3x5', STL-11000XM, Paramount ME

Related Designations for NGC6960

NGC6962

NGC 6962 is a nice barred spiral that anchors the NGC 6962 galaxy group. It is classed as SAB(r)ab. Oddly the NGC project classifies it as Sa. They apparently don't see the bar and ring structures I see. Arms seem a bit wide for the class so I'll have to go with the NED classification. The arms seem a bit unusual for either barred or spiral class to me. It certainly has a rather low surface brightness and the arms have only a hint of blue color being more white than seen in most galaxies of its type. The bar creates a ring. The outer arms seem to form out of nowhere not being attached to the bar or ring. Considering NGC 6964 right next to it and the odd ring structure I'm surprised Arp didn't put it in his catalog at least under the pair of galaxies classification.

The distance to the group is likely between 180 and 200 million light years. The latter figure is based on a type 1A supernova that was seen in NGC 6962 in 2002. The former on redshift and Tully-Fisher estimates.

There are quite a few NGC galaxies in the group. The larger galaxies are all members of the group. While some of the near star-like ones are dwarf members of the group, others are galaxies billions of light years distant. You need a scorecard to keep track. So I prepared an annotated image of those galaxies for which NED had redshift data. Those that are members of the group or at least have a redshift that fits within about 30% I identified by catalog entry name. A few "larger" ones had no redshift data. In those cases, I put a question mark after the name. For the many far more distant galaxies I only noted the redshift distance (5 year WMAP light travel time distance at NED) in billions of light years. The field contains a number of quasars. Some closer than some of the galaxies yet no galaxy is seen, just the quasar. Their host galaxy must be rather dim by comparison. But that's normal for quasars I suppose. "G" or "Q" before the distance identifies which they are. The label is immediately right of the object when possible. When not possible or the identification is ambiguous I drew a line from the distance to the object.

NGC 6962 and NGC 6964 were discovered by William Herschel on August 12, 1785. They aren't in either H400 program.
NGC 6963 was discovered by Guillaume Bigourdan on August 12, 1885, 1 year after NGC 6962 and NGC 6964.
R.J. Mitchel found NGC 6965 on August 27, 1857. Then Guillaume Bigourdan found it on October 2, 1891 resulting it being IC 5058.
NGC 6966 was found by Heinrich d'Arrest on July 26, 1865.
NGC 6967 was discovered by R. J. Mitchel on August 27, 1857.

14" LX200R, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for NGC6962

NGC6975

HCG 88 is a 4 galaxy group in Aquarius about 260 million light-years distant. Two dwarf members of the same group are shown in my image but didn't meet Hickson's magnitude limit for inclusion being too faint. An interesting paper on this group that is surprisingly readable is at https://arxiv.org/pdf/1509.06303.pdf .

The paper shows how Hickson 88A has a plume to the northwest indicating interaction in the past. It also shows that 88B has a shell structure indicative of it devouring a galaxy in the past. It also mentions how a typical image of 88C show it to have two arms but with special high dynamic processing a third arm becomes visible. Apparently, I do such processing as the arm is very obvious in my image. Not having an H alpha filter with a frequency to match this groups Dopler shift I couldn't do the H alpha image they did showing interesting pockets of star formation in these otherwise rather red and dead looking galaxies. It also notes that 88D, while classified as Sc shows two bright blobs on either side of the core that may be star forming regions at the ends of a bar so it could be a barred spiral. Maybe, I'm not convinced as I'd expect them to be symmetrical about the core but in my image, that doesn't seem quite the case.

The three NGC galaxies in HCG 88 were discovered by Albert Marth, NGC 6976 on July 12, 1864 and the other two a year earlier on July 20, 1863. However the galaxy NGC 6976 was independently seen by Guillaume Bigourdan 22 years later by Guillaume Bigourdan. Both he and Marth got the coordinates somewhat wrong and different such that Dreyer gave it the entry NGC 6975. Later he discovered the error and equated the two but kept the two entries resulting in today's confusion.

There were a ton of UvES objects in the field. This is NED's label for candidate quasars that lack spectroscopic redshift data and possibly other spectroscopic data needed to confirm they are true quasars. They also have a classification of Candidate Quasar for similar objects. My experience shows the latter, when fully studied are usually rejected as being quasars while the UvES ones rarely are rejected. So I included all UvES labeled candidates but not the others as the image was already very crowded.

NED has a couple galaxies with contradictory classifications. These two are labeled as being Candidate Dwarf galaxies yet their size in NED, as well as distance, make both much larger than our own galaxy. They are ASK 120385.0 and ASK 120178.0. The contradiction is even stronger with the latter which it also lists as a BrClG for Bright Cluster Galaxy and uses its position for a galaxy cluster 2.3 billion light-years away. Interesting a dwarf galaxy would be the brightest and largest galaxy in a cluster. I suspect the classification is from years ago before distance was known and these were thought to be members of the same group as Hickson 88. Somehow when new data shows this not the case, the classification never was removed.

Several galaxies in the annotated image are from the HCG 088:[dRC97] catalog as they appeared in no other at NED. NED gave them an error circle of a radius of 0.5 arcseconds, the best it usually gives. Yet none fit within this radius, usually be about 3 arc seconds from the stated position. This means my identification of these may be wrong. I picked the object closest to the position with a PSF proper for a distant galaxy and a magnitude similar to that stated in NED. Still a couple of times it was a very close call so I may have picked the wrong object. One had two listings one with just this catalog and another a couple seconds of arc away that listed several catalogs. When that happened I went with the multiple catalog entry as its position was within the error radius eliminating any question of identity and it was the one I had picked from the first entry.

The very bright (5th magnitude) B9III star, 5 Aquarii is just out of the frame to the north. It cast a bright blue halo over the upper part of the image and ghostly apparitions throughout the image. I had a heck of a time reducing these, some successfully others only partly so. One, unfortunately, overlayed HCG 88B. The part of its outer halo that extends to the Candidate Dwarf that's really far beyond the group. Removing it also removed the full extent of this halo toward this distant background galaxy that likely led to it being considered a possible dwarf member of the group. It can be seen in the image with the paper. I thought I'd moved it far enough out of the frame but that wasn't the case. The F5IV, 6th magnitude 4 Aquarii fully on frame wasn't blue enough to be a serious problem. Something about my corrector and very blue bright stars don't get along. O through early A bright stars are a problem for some reason.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for NGC6975