NGC7673

NGC 7673 is a very disturbed galaxy in the great square of Pegasus about 140 million light-years away by redshift. It is classified by NED as (R')SAc? pec; HII with a starburst core. Whew. The NGC project says simply Sc/P while Seligman says Sc? pec. It has a very large blue halo with a detached part well to the west as if part of a shell. A note at NED pretty well covers this one so I'll just copy and paste parts of it here:

"NGC 7673 is a nearby, luminous starburst galaxy with an inner
asymmetric spiral structure and an outer structure showing evidence of
ripples. This ripple structure of NGC 7673 is similar to that in
NGC 3310, possibly caused by a merger or interaction with another
galaxy (see Homeier & Gallagher 1999). NGC 7673 also contains an
extensive array of clumpy star-forming regions throughout its disk
(Casini & Heidmann 1976). The starburst is occurring in the inner
portions of the galaxy within huge clumps embedded within an abnormal
spiral pattern (Huchra 1977b; J. S. Gallagher et al. 2000, in
preparation). There is also an extended, somewhat disturbed H I disk
(Nordgren et al. 1997). The most likely scenario for the creation of
the starburst in NGC 7673 is either through a minor merger or, more
likely, from an interaction with a nearby galaxy, NGC 7677.
Although a massive starburst is occurring in the disk of NGC 7673,
the H{alpha}-line kinematics are relatively quiescent, with a low
velocity dispersion (Duflot-Augarde & Alloin 1982; Homeier & Gallagher
1999) consistent with a rotating disk. Figure 7 shows the UV/H{alpha}
and optical images for this galaxy. We find that NGC 7673 has similar
structures in its UV and H{alpha} images, with most H II regions
following the locations of the bright UV star clusters."

So while it could be the result of a merger these authors favor it having interacted with NGC 7677. I'm leaning toward both having happened in the recent past as NGC 7677, while obviously damaged doesn't seem sufficiently damaged to have wrecked so much havoc on NGC 7673. The distant shell like plume to the west, if a shell, would be a good indication a merger is involved. For NGC 7677 to be involved it must be at about the same distance as NGC 7673. That is the case. NED shows its redshift distance to be 150 million light-years. The actual difference is likely far less with most of the difference due to the rates these two are moving in relation to each other as seen from here. Non-redshift measurements put it at 160 million light-years. So it is likely NGC 7673 is likely further than its redshift distance. Due to how messed up it is no non-redshift measurements are available for it.

NGC 7677 is classified by NED as SAB(r)bc: with a starburst core. The NGC project says SBbc while Seligman says SBbc?. The pair was discovered by Albert Marth on September 5, 1864. Using a distance of 150 million light-years for both I get a diameter of NGC 7373 of 61,000 light-years not including the distant piece. When that is included its size is 95,000 light-years. NGC 7677 is 97,000 light years in size including the very faint plumes beyond the wide arms.

An HST image of NGC 7673 and more discussion about the galaxy can be seen at http://www.spacetelescope.org/images/heic0205a/ .

Two very bright red stars between these two galaxies cast a nasty gradient across both galaxies. I had to greatly dim the stars while dealing with it.

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

Related Designations for NGC7673

NGC7686

NGC 7686 is an open star cluster in Andromeda. It was discovered by William Herschel on December 3, 1787. Its Trumpler class is IV1p. That translates into a star cluster of widely scattered stars of fairly even brightness with a low star count. For those not familiar with this classification scheme the Roman numerals range from I to IV indicating how concentrated and easy it is to separate the cluster from the background. With I being a very obvious cluster that stands out with a high concentration of stars to IV which is scattered and difficult to tell cluster stars from background stars. The numeral ranges from 1 to 3 indicating how similar in brightness the stars are with 1 being very similar to 3 being a wide variation. The last letter tells if the cluster is (p)oor, (m)edium or (r)ich in stars. The cluster is listed as being 15 minutes of arc across so all of it is in the image.

Being such a poor cluster why did I take it? It is in the original Herschel 400 observing list and my system grabs data on these only when nothing better is in position. That means it might take one frame then a better object is now high enough so it moves to that better target. Eventually, sometimes years later I have enough on one of these to process it. That's the case here though I only had 1 color frame for each color. No satellite issues so I went with that one frame rather than wait possibly many more years to finish it. For star color one of each color is plenty sufficient. I take two because that makes it easy to remove satellites without cloning them out which I'm very poor at doing without making it look very obvious.

My visual log from July 10, 1985 with my 10" f/5 reads: "Small, poor but tight cluster, mostly west of a 5.5 magnitude orange star that hides the cluster with its brilliance. Reminds me of a smaller, poorer version of NGC 2362 around Tau Canis Major only with an orange star at its core." I went on to note only 12 stars were seen I could say were cluster members. Not sure about where I got that "tight" description. I can't say I see that in this image. The magnitude of the bright star is a bit high as well. Not sure where that came from. There is an orange 5.5 magnitude star 1.5 degrees southwest. Could I have been on the wrong star? I don't see anything resembling a cluster around it however but I may have picked up the wrong magnitude value using the wrong star. I need a time machine to go back and ask myself what I was thinking 30 years ago. Dreyer's description from the NGC reads Cl, P, lC, st 7...11 which translates to cluster, poor, little condensed stars of 7th to 11th magnitude. In any case, the image is on the coordinates for the cluster.

Obviously, the field is filled with a wide variation of stars so where does this similar star brightness come from in its classification. Apparently, the bright stars in the image aren't true cluster members or aren't considered as such. I couldn't find a distance to the cluster. Wikipedia says 900 light-years, many sites like WEBDA and SEDS don't give a distance at all. I've seen a wide range of values, usually without sources. Hipparcos data has the distances to the 4 brightest stars in the field. All are reddish stars. According to that catalog, the brightest star is magnitude 6.2 and a K5III star at 856 light-years, rather close to the 900 light-year figure for the cluster. The second brightest star at magnitude 7.7 and K0 class to the southwest is put at 1260 light-years. The orange star above it and a bit to the right two-thirds of the way to the top is magnitude 8.9 and K0III at 1221 light-years. Rather close agreement to the previous star. The only other star I found with Hipparcos data is the orange star directly above the brightest star at magnitude 9.51 and G8 (seems rather red for that classification) which is listed at 86 light-years. Star clusters, unless old are mostly blue stars so I assume it is mostly blue stars that form the cluster. But which ones? Also could one or two of the red stars be members. Probably not the two main sequence stars but the red giant ones maybe though their distance varies by more than 300 light-years meaning only one if either is a cluster member. Heck, I'm not even sure there's a cluster here or just an asterism. Though there are some papers on variable stars in the cluster and one with only a title saying they surveyed F7 type and earlier stars "around" this cluster. Could that mean they can't identify true members? I found one paper on proper motion of stars in clusters but apparently while this cluster was one they looked to it didn't have usable data from Hipparcos. I already had run into that issue above.

So I still can't tell what is the cluster, just that it's in this image someplace. Most coordinates put it just a few seconds of arc east of the brightest star. Other than that you're on your own here. Maybe at a shorter focal length, a cluster can be seen.

Due to no need for high resolution I'm posting this one at 1.5" per pixel rather than my normal 1" per pixel.

14" LX200R @ f/10, L=4x10' RGB=1x10', STL-11000XM, Paramount ME

Related Designations for NGC7686

NGC7694

NGC 7694 is an irregular Magellanic galaxy in Pisces, about 90 million light-years distant. NED and the NGC Project both class it as Im Pec? The MCG catalog has a couple comments I can't understand. It reads: "It is similar to M 82..." Then adds: "...merged with a star brighter than itself." How an irregular dwarf galaxy can be compared to M82 baffles me. Both are starburst galaxies but that's about all I see in common. It does have a bright off-center region that I suspect is the "star". I don't see it as anything but the brightest part of the galaxy. No other catalog makes reference to a star there that I could find except for the HST Guide Star Catalog which lists lots of things as stars that aren't. It does the same for NGC 7695, the companion to NGC 7694. So it is worthless for this purpose. The HST hasn't imaged the area so that can't help either.

I included this one on my list for its irregular shape and lots of HII regions that show as blue blobs in my image. It is also a strong IR emitter being in both the IRAS and 2MASS catalogs so there is a lot of star formation going on that is hidden by thick dust. Its the dust warmed by these new stars that likely accounts for the IR radiation.

Its companion is NGC 7695 which is classed as cE2? Pec? by NED and S0 by the NGC project. Quite a disagreement. The cE in cE2 means it is a compact elliptical galaxy and the 2 means it is somewhat elongated. Its core is elongated about as I'd expect for an E2 galaxy but it has an extensive even more elongated halo. This is what likely caused the S0 class by the NGC project and the Pec? label by NED. I won't try to guess who is right. Since they use different classification systems both may be "right."

NGC 7694 was discovered by William Herschel on September 20, 1784. It isn't in either H400 program. NGC 7695 was discovered by Albert Marth on November 14, 1863.

More important is whether these two are interacting. The massive star formation of NGC 7694 could be due to other factors but it is often caused by interaction so it's quite likely they are interacting as they have very similar redshifts. A compact galaxy holds its stars quite tightly which results in little distortion unless it is involved in a direct hit with another galaxy. Just passing by wouldn't cause a lot of distortion but could cause the larger, slightly non-symmetric, halo we see around NGC 7695. An irregular galaxy has a loose hold on its contents so can be greatly affected by a close encounter.

I wasn't going to make an annotated image but then I saw there were 5 asteroids, 4 that were too faint to point out without annotation and a few galaxies were in NED with redshift information so I decided to make one anyway. In doing so I found one galaxy, WIG R00J233224443-02450563, with a redshift of z=1.110560 which puts it at over 8 billion light-years. That is the WiggleZ Dark Energy Survey. It tends to list very high redshift galaxies. Makes me wonder if these are quasars rather than galaxies that I am seeing. Or is it just a very bright but normal (for one that far back in time) galaxy I'm picking up. It is in the right side of my image and labeled with its magnitude as well as distance using NED's 5 year WMAP calculation. For more on the WiggleZ survey see: http://wigglez.swin.edu.au/site/ The page says it covers galaxies with a redshift of 0.2 to 1 yet this one exceeds 1 though not by a lot. For more on the survey including where the name comes from see: http://www.science.org.au/nova/115/115key.html

It seems most asteroids I catch in my images are moving in retrograde motion. These are the exception as all are moving in prograde that is to the east (left).

Sloan image:
http://cseligman.com/text/atlas/ngc7694wide.jpg

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

Related Designations for NGC7694

NGC7700

NGC 7700 and 4 others make a nice five galaxy group about 220 million light-years away in the constellation of Pisces south of the circlet. Oddly three of the galaxies (MCG-01-60-005, NGC 7700 and NGC 7699 make up the triple galaxy group USGC S290. Four of the galaxies make up the galaxy group LGG 476. I can't find which 4 it includes. MCG-01-60-005 is more distant than the others from its center so I will assume it is the odd galaxy out. A wider field of view will pick up two other galaxies NGC 7694 and NGC 7710. These are at less than half the distance of the 5 in my image so part of an entirely different group. I can't fathom why all five in my image aren't considered a group but three or four at a time are.

NGC 7700 is an S0+ edge on spiral in NED and S0-a by the NGC project, that doesn't make it into any of the flat galaxy catalogs but is a nice edge on galaxy. MCG-05-60-005 is listed as an SB(s)d spiral. NGC 7699 is listed as SBa? by NED and Sa by the NGC project. It looks barred to me, however. Both NGC 7700 and 7769 were discovered by Albert Marth in 1864 using a 48" scope so are two Herschel missed. However, William Herschel did discover NGC 7701 in 1784 with his 18.7"reflector. It's not in either H400 program. While the two he missed are fainter they are visible in today's 17.5" scopes and probably 16" scopes but with his speculum mirror, Herschel was at a big disadvantage. IC 1501 is classed as S0o which I assume to mean it has an unusual number of O type stars. Its outer halo does appear a faint blue color. Otherwise, I don't quite see this. O stars are unusual in S0 galaxies. IC 1501 is classed SAB(s)bc pec: with HII emission. I didn't pick up the HII however. Nor do I know what gives it the peculiar status. Other sources say SBbc without the HII nor pec: reference. It was the last to be found on October 9, 1891 by Stéphane Javelle. I don't know what size scope was used. Since he was an accountant turned astronomer (I was a CPA and accounting prof) I sort of identify with the guy.

While nearly another 100 galaxies are listed in NED in my frame there's no distance data for any of them so I've not bothered to point them out on the annotated image.

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

Related Designations for NGC7700

NGC7711

NGC 7711 is located in Pegasus about 170 million light-years distant and classed as S0 by both NED and the NGC Project. It is one odd galaxy that Arp overlooked though it sure belongs in any list of peculiar galaxies. Look at its core region and it is a pretty normal looking S0 type galaxy but on the right, there's a blob that someone at Galaxy Zoo decided made it a barred S0 galaxy. That appears to be wrong, however. Further right and down you see faint "debris". What is that? On the left side appear to be two spiral arms but they don't appear on the right side. Then right across the core of the galaxy is a faint dust lane way out of the plane for the "arms". How can all this be explained? One paper does have an explanation that accounts for much, but not all of this. The paper covers several other galaxies. Coverage of this one begins on page 8.
http://arxiv.org/PS_cache/arxiv/pdf/1102/1102.2905v1.pdf

Their explanation is that the "arms" are star trails from a dwarf orbiting about the main galaxy in an eccentric orbit that passes well away from the galaxy on the left side but near it on the right. We are seeing two passes around the galaxy. The blob on the right is (closest to the galaxy) the trails where they are compact on that side and the dwarf itself (the part to the south) -- see the annotated image. They don't mention the dust lane nor the "debris" to the southwest. I am going to guess the dust lane is normal to the galaxy itself before this encounter. Due to the encounter, much of the dust has been expelled leaving just a faint remnant of the original. The "debris" likely stars expelled from both galaxies due to the encounter but mostly due to the dwarf. That's my barely educated guess anyway. The galaxy was discovered by William Herschel on October 14, 1784. It isn't in either H400 program.

UGC 12673 in the lower right corner is the only other galaxy of note. It appears to have an off center nucleus. NED classes it one place as Sc and another as Sdm.

There are three asteroids in the image. Two very faint. I've marked them all in the annotated image. The bright one would normally have the color frames barely showing after it but in this case, the color data was taken a different night when it was no longer in the frame.

There are several galaxy clusters in the frame with redshift determined photographically. That's the P after the distance. The core galaxies often had a different distance estimate. They too were photographically determined. In one case the galaxy had no distance estimate so gets a question mark.

(60357) 2000 AG96 is at magnitude 18.3
(298286) 2003 AG3 is at magnitude 20.1
(298506) 2003 VK9 shines at magnitude 20.2

Half the L data was taken on a night I was able to cool the camera 5C further than the other night. This temperature difference changed my image scale so normal aligning wouldn't work. Registar to the rescue. It handled the two different image scales quite well. I ended up processing the luminance channel twice as I didn't catch this the first time. The difference was sufficient to show all stars at the left edge as close doubles and highly elongated on the right side when aligned normally. The difference between the warm and cool nights amounted to about 8 pixels at the edges. I used the larger image scale as the reference frame to avoid dark edges.

14" LX200R @ f/10, L=8x10' RGB=3x10', STL-11000XM, Paramount ME

Related Designations for NGC7711

NGC7720

The Abell galaxy cluster 2634, in the north central part of the Great Square of Pegasus, is listed at NED as consisting of 125 galaxies over a 3 degree radius from a point slightly southwest of NGC 7720 as labeled in the annotated image. I don't quite understand the count of only 125 galaxies as there are nearly that many known to be in the cluster in my very small field of view. While some appear members of a cluster some 1.5 billion light-years distant most are at about the 0.4 billion light-year distance to the Abell 2634 cluster. It is listed as morphology class BM 2. This would indicate it has more than one major cD or bright cluster galaxy like the Coma Cluster. While NGC 7720A is a bright elliptical it doesn't seem large enough to qualify. Though several other large ellipticals are in the image they too aren't listed as cD or as major bright elliptical though IC 5341 comes close. Maybe it is just the large number of quite large ellipticals that gives it this morphology rating.

NGC 7720 is a huge elliptical. It was discovered by William Herschel on September 10, 1784. It's not either H400 program. I measure it as just under 300,000 light-years in diameter though that halo may also include the halo of NGC 7720A, in which case that may be too large. Still, I think it pretty close to the correct size. Papers indicate it has hundreds of globular clusters though I didn't pick those up. Like most clusters, it is composed almost entirely of elliptical and S0 galaxies. The only classic spiral in the image may be NGC 7726 at 330 million light-years. That may put it too close to be a true member of the cluster or it may just have a high velocity compared to the average cluster member. Several other galaxies at about that redshift are also in the image though most are 370 million or greater distance. The identification of NGC 7726 is somewhat of a question mark. Entry 7726 is an obvious error and this is the most likely object seen but mislocated. Still it can't be proven to be what was originally seen. See the entry for it at the NGC Project for details. The NGC project site is down for rebuilding which may or may not happen. NGC 7726 is the best guess as to what Lewis Swift was seeing on August 8, 1886.

The strange galaxy in the image is LEDA 085553 at the top edge. It is a very irregular galaxy also a bit close to be a cluster member at 350 million light-years. It consists of many blue star clouds all in a single halo of stars. It is one of only two blue galaxies in the entire image. Even NGC 7726 is mostly red and thus containing mostly old stars. The other blue galaxy is LEDA 085609 southeast of NGC 7720. It is listed as S/I. It appears in my image to be a blue spiral with a large plume to the east. It may be a disrupted spiral. The only other galaxy with any significant blue is the slightly blue LEDA 085559 also listed as S/I.

Another galaxy worth looking at is CGCG 476-080 on the western edge of the image. While listed as S0 it appears to be a ring galaxy though this isn't mentioned at NED.

In annotating this image I listed all with redshift data at NED along with classification if given. Those listed only as G or by their classification rather than catalog name had no catalog name other than one that consisted solely of its sky coordinates. If no classification was available I just used G for galaxy. This is likely the densest annotated image I've done. They are usually fun but it gets boring when this dense. Took a good 2 hours. Hope it was worth it.

The two IC galaxies were found by Herbert Howe on November 27, 1899. Most sources just say 1899 but Steve Gottlieb as this date. I don't know his source.

This was taken on about the best night I had in August 2013. At least I made no notes about it being poor in some way like I did nearly every night this summer and fall. Still, most of the Luminance data came from a September night. Due to sky conditions, I started taking only color data on the commonly poor nights and only luminance on the nights worth doing it. I now have many objects with no luminance waiting for better conditions next year. After those piled up, I gave up and went back to using whatever the night gave me and cussing a lot.

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

Related Designations for NGC7720

NGC7731

Why I imaged this field is a mystery. It wasn't on my to-do list yet the coordinates for the center of the image were. I find nothing on what drew me to this field. But it contains some interesting galaxies so worth the effort.

This was another night of severe smoke that greatly limited my ability to pick up the faint ring around NGC 7731. The only color image of it I found shows the outer ring quite blue but that just didn't get through the smoke. Brighter blue did. Nor did the smoke stabilize seeing as it often does. I should have picked up detail in the disk but didn't. It is considered today as a companion to nearby NGC 7732 though as late as 1976 it was considered well behind NGC 7732 and not related. It doesn't appear disturbed by any interaction with NGC 7732. It is classified as (R)SBa pec: though some sources call it SB0

NGC 7732, on the other hand, is not normal looking. The CGPG says of it: "Disrupted and badly 'dented' Sc". Apparently, galaxies need body shops to fix up dents from accidents with other galaxies. NED classifies it as Scd pec. Redshift puts it at about 120 million light-years, 30 million closer than NGC 7731. The difference may be real or may just be due to their relative velocities. Both were discovered by Albert Marth on October 27, 1864.

IC 1504 is the spiral galaxy at the top of the image. It is a near edge on Sb spiral galaxy. It certainly is unrelated to the other two as its redshift puts it at almost twice the distance at 270 million light-years. It does appear to have a plume of some sort to the northwest above the plane of the galaxy though this may just be due to perspective. In any case, it appears more interesting than I expected at first glance. It was discovered by Stephane Javelle on August 19, 1892.

There's a 4th galaxy of some angular size in the upper right corner. It is the irregular galaxy PGC 72075. It has the same redshift as IC 1504 to is likely related. Did it cause the plumes in IC 1504? There's also PGC 72127 to the north of IC 1504 out of my frame with a similar redshift. Neither appears to be the cause of the plume to my eye. Maybe it is due to something it ate long ago.

This field is in Pisces just east of the circlet.

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

Related Designations for NGC7731

NGC7741

NGC 7741 is a rather low surface brightness barred spiral inside the Great Square of Pegasus. I found its distance rather uncertain. Adam Block put it at 30 million light-years on his AOP pages. NED shows distance estimates from 40 to nearly 60 million light years with a mean of a bit under 50 million light years. In any case, its redshift distance of only 19 million light years seems unreliable.

I lost this one on the hard drive. Probably because the color data was so poor in green and especially blue I didn't think it worth processing. Somehow I moved its data to an already processed object's file and forgot about it. This was taken back in December 2008. When I saw an image of this posted on a forum it looked familiar and did a search of the hard drive turning it up. I had to struggle with the poor color data and probably should have retaken it. Still, I think it turned out better than it should have looking at the raw data.

There is massive star formation going on in the bar making it rather blue in color from all the super hot stars recently formed there. My poor color data turned it more white than blue as it should be. There are a couple of HII regions just north and south of the bar. They appear more orange than pink. I don't know if this is due to dust or my color data problem. It was discovered by William Herschel on September 10, 1784. But it's not in either H400 program.

This field isn't covered by the SDSS. NED has little on the area as well. It does show that the galaxy cluster ZwCl 2341.1+2544 accounts for most of the field galaxies as it is centered a short distance southwest of NGC 7741 and is 30 minutes across which is about the width of my field. I found no distance to it. NED lists it as having 101 members.

Adam Block using the new 32" scope atop Mt. Lemon at the University of Arizona's SkyCenter took this image of the galaxy a short while ago.
http://www.caelumobservatory.com/gallery/n7741.shtml
Too bad there aren't any laminar air flow mountains here in Minnesota.

14" LX200R @ f/10, L=4x10' R=2x10'x3 GB=1x10'x3, STL=11000XM, Paramount ME

Related Designations for NGC7741

NGC7750

NGC 7750 is a spiral galaxy in Pisces about 120 million light-years distant. It was discovered by William Herschel on August 30, 1785. It is classed as (R')SB(rs)c pec: at NED and SBc/P at the NGC project so both see it as peculiar I see I mentioned it in my text of Arp 68.

That must be why I imaged it though it's not on my to-do list. I see I did put 7755 on the list but with the wrong declination. It is too low for my latitude. Did I discover that and then looked for something of similar RA to image? Hard to remember back to August 18 of last year when this was taken.

Nothing else in the field has any distance data with only a handful of background galaxies even being listed in NED. There are two asteroids in the image. Both with oddly curved trails. Remember the story of Arp 192's phantom "jet"? Its asteroid trail appeared curved so no one considered the possibility it was an asteroid. Now I have two curved trail asteroids in this image, both with the same curve. Yet my tracking is smooth showing no sign of any tracking errors which would alter the stars as well as the asteroid creating short vertical trails for all stars. So what is going on? Wish I knew! The asteroid east of NGC 7750 is (68675) 2002 CV123 at magnitude 19.3. The one above NGC 7750 is (151085) 2001 VK83 at magnitude 19.7.

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

Related Designations for NGC7750

NGC7765

NGC 7768 is the cD elliptical galaxy that anchors the Abell 2666 cluster. It has far fewer globular clusters than would be expected for a galaxy of its size and location. The cluster is about 350 million light years distant and located in the northeast part of the Great Square of Pegasus. As Abell clusters go this is a small one. In the annotated image I've noted those that are likely true members of the cluster by showing their catalog name. As space was tight and galaxies have many different catalog entries I usually used the shortest to keep clutter down. It was discovered by John Herschel on September 5, 1828.

While several of the galaxies show signs of interaction the most distorted is CGCG 477-016 at the top center of my image. NED simply classes it as a LINER spiral. No mention of the huge, faint plume going west (right) from the southern end of the galaxy. A note at NED isn't so silent about this galaxy saying:
"This galaxy is also probably not a classical ring galaxy. The brightest isophotal levels of the optical and IR images (Fig. 11) show a very peculiar "theta-shaped" system, with a faint bar (which is quite prominent in the IR) and peculiar filaments extending from the ends of the bar. The galaxy shows intense star formation in the regions of the closed portion of the theta-shape. With the exception of the Seyfert rings, this galaxy is one of the few in the sample which showed H{alpha} emission in its nucleus. The most remarkable feature of this galaxy is the huge plume and ripples in the outer regions of the galaxy seen in the blue at low isophotal levels. This suggests that the system is a merger remnant like NGC 7252 (the so-called "Atoms for Peace" galaxy of Whitmore et al. 1993). We are unaware of any major companion near LT 36, and so if the plume and ripples are part of the debris of a highly disrupted companion, there is no sign of the nucleus of the accreted object."
http://adsabs.harvard.edu/cgi-bin/bib_query?1997AJ....113..201A

I'm going to possibly disagree with the last statement above. Looking at the plume it seems to curve behind the galaxy then come up about the middle and arc over to dive into the gap in the theta structure on the western side. That part that dives in is bright and seems to have a star-like "core". Could this be the trail a colliding galaxy followed with the remains of it the bright part of the arc? Is the starlike core then the remains of the core of this galaxy? No paper suggested this so likely not the case but it sure gives that appearance to me.

NGC 7765 was found by R.J. Mitchel on October 12, 1855.
NGC 7766 and NGC7767 were found by Ralph Copeland on October 9, 1872.

Galaxies too distant (none were closer) to be a member of the cluster are just labeled with a G plus their distance in billions of light-years. NED listed no quasar or quasar candidates in the field. Many interesting galaxies had no redshift data. Most weren't even listed at NED. I left those few that were at NED without a label. While the field has been imaged in the DR8 data release NED is yet to pick up the data. When that is included I assume many more will have redshift data.

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

Related Designations for NGC7765