NGC7082

LEDA 167461 UPPER LEFT CORNER


NGC is an "Open Star Cluster" in Cygnus about 1.4 degrees south-southwest of M39. It was discovered by William Herschel on October 19, 1788 and is in the second Herschel 400 program. That is why I imaged it. I certainly didn't image it because it was a great target. In fact, I can't see a star cluster here. There are some bright stars that visually make a possible cluster but half are blue and half are red. This could happen if we are seeing the cluster just as the major stars are turning to red giants. I find that unlikely but possible. John Herschel's observation of the cluster reads: "A 10th magnitude star, the chief of a pretty rich, large, coarse cluster. Stars 10th to 13th magnitude." His position is off by a minute from that 10th magnitude star.

It may be smoke screwing up my photometry but I am finding the brighter stars in this image as 8th magnitude, not 10th. I still don't see what I'd call a cluster. I am sure I logged this one when doing the second program but my log got lost in the move to Minnesota. I can't recall anything from 40 years ago when I likely looked at it. This one makes me wish I still had the log.

WEBDA does indicate this is a true cluster with an age of 170 million years. They put its distance at 5100 light-years with only 0.24 magnitudes of reddening. They frame the cluster much as I did but about 5 minutes of arc to the south of my center. Still, it appears the cluster is fully within my field, just where is the question. In the POSS 1 red image where the blue and red stars are simply white, there appears to be a scattered cluster. Seen in color, I expect the main stars to be of a similar color and thus the wide range blocks my brain from seeing it as a cluster.

This is yet another image saved from the severe smoke. I had great nights but all severely hit by smoke. In this case, the smoke caused severe halos around the 8th to 10th magnitude stars in the luminance frames that I found virtually impossible to deal with. I gave up in fact. This image is made from the best red, blue and green frames. By the time those were taken the smoke was even worse but dimmed things enough the halos were easy to deal with. While I had several good red frames I only had one green and while I used a blue frame it was severely dimmed by the smoke. I had to push blue severely to make the color image. I used all three as a pseudo-luminance frame without pushing the blue data meaning its more like green and red as blue was too weak to add much if anything. I found only two images on the net in color of this field. One with a DSLR that made all but a couple stars vivid blue. Since this is on the edge of the Milky Way I doubt that is at all correct. A second very short image of the center of the cluster does show the same color range I am getting but without anything below about 12th magnitude, it's hard to judge. Since my version is pleasing, if not correct, I'll leave it at that.

A very sharp-eyed viewer may find a faint galaxy in the upper left corner. It didn't record at all in the blue and barely in red and green. It is LEDA (PGC) 167461. I find nothing on it. It is just a faint smudge in my image so possibly a nearly face-on spiral.

Considering I can't really see the cluster I won't be revisiting this one even under the best of conditions.

14" LX200R @ f/10 Pseudo L=3x10', RGB=1x10', STL-11000XM, Paramount ME

Rick

Related Designations for NGC7082

NGC7086

NGC 7086 is an open cluster in Cygnus. It was discovered by William Herschel on September 21, 1788. WEBDA gives its age as about 140 million years and puts it 4200 light-years away. It is a Herschel 400 object, a list I'm slowly working on imaging when possible, many are too low for my current skies. My log entry with a 10" f/5 scope using up to 100x on a humid night (June 14, 1985 at 3:30 UT so not quite end of astronomical twilight) of low transparency reads: "Scattered, irregular open cluster of a dozen or so bright stars seen over a field of unresolved stars." It appears I never went back for a second look. NED doesn't list a single galaxy in the image. There is a 19th magnitude very blue star-like object well north of NGC 7086 and a bit east at 21h 30m 37s +51d 43m 5s that I couldn't find a thing on. Most likely a very blue-white dwarf but no one had it listed that I found.

According to my log, I took additional data on this two nights later but I can't find it anyplace on the hard drive. Could be I started a run that clouds aborted and I didn't mention that. I just can't remember back that far. So I made do with the data I had. It is sufficient for a cluster but not for some dust that I saw in the image. Just too noisy so I processed it out.

14" LX200R @ f/10, L=3x10' RGB=1x10', STL-11000XM, Paramount ME

Related Designations for NGC7086

ngc7094

NGC 7094 IS a planetary in Pegasus not far from the famous globular cluster M15. The central star in this nebula is a rather odd star. It is known as a hybrid PG 1159 star. What this means is that it, first off, has an unusual amount of hydrogen left in its atmosphere. Secondly, it is a variable star. White dwarf stars are normally dead stars only giving off heat and light stored in them when their nuclear furnaces were still working. When they die they throw off the outer atmosphere that still has hydrogen, creating the planetary nebula, and retaining the core of heavier elements created by the nuclear furnace. They get a small amount of energy from gravitational collapse as they cool but they shouldn't vary in brightness. But some do. It is thought that the outer atmosphere of the star becomes more or less opaque depending on the ionization level of certain heavy elements such as iron in the atmosphere. It is this variation of ionization that makes the star appear to vary in brightness. In fact, it doesn't, it's just that the atmosphere blocks the light at times. Such cycles are very irregular. In this case, the star varies at a rate of 2000 to 5000 seconds. Since my exposure of this guy was 6000 seconds it may have varied 3 times during my exposure! Thus catching this isn't easy, nor would I try. I knew this before I took the image. What I didn't know was that it shares the field with a very faint galactic cirrus nebulosity. Since I didn't know it was there I severely underexposed the image as do most who take this planetary since the planetary is bright compared to the nebula. I need to go back and try a much longer exposure. But something is reflecting into my field. When I centered the nebula a rather bright ghostly nebula appeared to the west of the nebula. I have no idea where the reflection came from. To get rid of it I had to lower the object. Raising it didn't help. Since the nebula is mostly "below" the planetary that means I lost some of it. I can't find any reliable distance data for this planetary. Again, if anyone knows let me know. Contrary to the above galaxies, this planetary is a good target for a 10" scope but have narrow band filters like the UHC or OIII handy as you'll want them to see more than a blob of faint blue light. It was discovered by Lewis Swift on October 10, 1884.

Conditions went from fair to bad during this exposure. The loss of resolution caused the blue and especially green frames to be "defocused" causing the odd blue-green halos around stars as well as making them larger than usual. Yet another reason to redo this one but I have such a backlog of objects not taken the first time it is hard to go back and reimage those I should.

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

Related Designations for ngc7094

NGC7102

NGC 7102 is a galaxy that seems to fit Arp's category for spirals with a small, high surface brightness galaxy on an arm. The companion is LEDA 214783. The pair are about two hundred million miles distant under the nose of Pegasus. While the redshifts are slightly different it appears they are interacting. The spiral arm leading to the companion has been highly distorted compared to it counterpart on the northern side of the galaxy. NED classifies NGC 7102 as SB(rs)b? while the NGC project says simply SBb. I find no classification for the companion. These are the only two galaxies in the image with redshift data so no annotated image was prepared.

NGC 7102 may also be IC 5127. There's nothing at the position given for IC 5127. According to the NGC Project NED returns "There is no object with this name in NED". This is no longer correct as NED now considers it as the same as NGC 7102. However, as the NGC project says SIMBAD still does return "Not present in the database."

NGC 7102 was discovered by Albert Marth on October 16, 1863 while Guillaume Bigourdan found IC 5127 on October 27, 1894. Though there's nothing at that position. It appears he used a reference star whose position was off by 4 minutes of arc. While this doesn't fully explain the error it does explain much of it. Still, it gets within a minute of arc of NGC 7102 which has convinced many, including NED, they are equivalent and Bigourdan wasn't seeing a comet or other transient object. The confounding factor here is that Bigourdan also recorded NGC 7102 and did so at its correct position the same night. If not for this there'd be no question they are the same object. You can read more on this at the NGC Project under NGC 7102. That site is being rebuilt so instead to go Seligman's site for IC 5127. http://cseligman.com/text/atlas/ic51.htm#ic5127

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

Related Designations for NGC7102

NGC7127

Sometimes I wonder why I research my objects. This is such a case. The more I looked the more confusing things became.

NGC 7127 is listed as an open cluster in northeastern Cygnus. I'd normally give a distance at this point but my research turned up nothing but confusion. I found only one reference, a Polish Wiki page, that gave a distance. They gave a distance of 4700 light-years. But when I checked the footnote for the distance that took me to a SEDS page on the cluster that never gave a distance! WEBDA, my usual go-to source for open clusters, had nothing on it but a position. But several of the stars were bright enough that parallax data from Hipparcos was available from The Sky's database. That gave distances to 4 apparent cluster members, two about 200 light-years and two of about 2000 light-years. These were the 4 most "obvious" cluster members. If right it would indicate this is not an open cluster at all but an asterism. So I went to the papers listed at SIMBAD. The first is for a galaxy NGC 7217! Yikes, the wrong object entirely. But I have taken this galaxy! The other references at least applied to open clusters.

One says it is a real open cluster with an age of 100,000,000 years and a distance of 5700 parsecs (18,500 light-years). So that means the 4 stars with Hipparcos data are foreground stars. http://cdsbib.u-strasbg.fr/cgi-bin/cdsbib?2012A%26A...542A..68P

The cluster/object looks to be in two parts one to the northwest and the other to the southeast. But this is seeing it projected in 2D. The 3D view may be quite different.

The cluster/object was discovered by John Herschel on September 25, 1829.

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

Related Designations for NGC7127

NGC7128

NGC 7128 is an open cluster in the constellation of Cygnus. It is one of the prettier clusters in the original Herschel 400 list. The distance to it has usually been put at about 7500 light years but I found a well-researched paper indicating it is more like 13000 light years away give or take 10%. This puts it on the edge of the Perseus arm of our galaxy rather than between arms. Since it is a rather young cluster, something over 10 million years old, it wouldn't have had time to move out of an arm as the old distance estimates said. Another reason I like this new distance estimate.

I was drawn to this cluster by Dreyer's description which mentioned that it contained a ruby star. Always liking carbon stars and other very red stars I had to view it at the first opportunity. When I did I found it contained two bright orange stars and a third fainter one but I never did see the ruby star Dreyer mentions. Still, it is a great cluster visually due to the color contrast of those giant K stars standing in contrast to the blue A and B stars it contains.

It was discovered by William Herschel on October 14. 1787. My entry from the original H400 program using my 10" f/5 at up to 100x on a fair-but humid night on June 14, 1985 reads: "Small, round cluster circled three-quarters of the way around by bright stars. How could it be called "sparse" when it is such a small tight cluster. It's not condensed but isn't sparse!" By now if you've been reading through my site you are seeing a lot of May 1985 and later entries all saying humid. This is because I was working from my old cabin on the lake. I had to set up right along the shore. Down there it is always very humid. My observatory is on a very different part of the lake, atop a hill with the telescope over 60 feet above the lake and about 130 feet back from it. While it can be humid here as well It doesn't have the water vapor that rises from the lake giving near 100% humidity and ground fog. I'm now usually above that now.

Clusters need the very best nights for seeing as otherwise the stars just look lousy. I hate to "waste" a good night of seeing on just stars but when it's one of your favorite visual clusters you do so. Though I cheated and only used one 10 minute shot for each color channel. When there are no faint fuzzies you can get away with that. Oddly when I put it together the color was so strong I had to turn it down. Usually, I have to boost the color, especially of clusters. Not this time. I don't know why this turned out so differently as I didn't process it any differently.

Sorry, no faint fuzzies in the background. Just too much dust and gas in ours to let me see anything beyond. The image was taken September 17, 2009. I'm not gaining on my backlog.

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

Related Designations for NGC7128

NGC7132

NGC 7132 is a somewhat disturbed appearing spiral about 50 minutes of arc northeast of Enif, the nose of Pegasus. Redshift puts it 360 million light-years distant while a lone Tully-Fisher measurement says 270 million light-years. As the spiral structure appears rather disturbed and hard to measure rotation curves when seen this face on I'm going to go with the cosmological redshift distance of 360 million light-years. That would make it about 90,000 light-years in diameter. NED makes no attempt to classify it. The NGC project says Sc while Seligman says Sc? likely due to its disturbed appearance. It was discovered by Lewis Swift on October 18, 1884.

The galaxy has two main arms that appear rather normal though the one to the west does split into two. In the southern part of the galaxy, a dark cloud cuts horizontally across the galaxy and has a bright horizontal region above it. The bright region has a diagonal dark cloud set its left side off from the spiral arm it would otherwise cross. On the other side, it seems to pick up again only fainter but then curves north toward the outer edge of the galaxy while the dark cloud below it ends abruptly. M63 has a similar dark cloud that is thought to have been caused by dust left behind by a dwarf it is digesting the remains of which may be to the west side of M63 as a squiggle of a galaxy. In the case of NGC 7132, I don't see any remains though other parts of the galaxy's bright regions don't seem to conform to the structure of the two main arms as if the galaxy may be composed of two merging systems. Unfortunately, I can't find any papers discussing why it looks as it does much less supporting my hypothesis.

Only one other galaxy has redshift data at NED, it's the red spiral or S0 galaxy to the south, CGCG 427-023 which has a redshift similar to that of NGC 7132. Thus they are likely companions but it shows no distortions so I doubt it could be interacting with NGC 7132. I measure its size at a bit under 80,000 light-years. Assuming they are at the same distance then their separation is only 690,000 light-years.

With only two galaxies to annotate I wasn't going to prepare an annotated image but then three quasars, all quite distant at about 11 billion light-years did change my mind as they would be impossible to point out otherwise. A fourth at a similar redshift is just out of the field to the south.

A couple other galaxies are obvious in the field beside the usual faint background fuzzies. I've labeled them as well but with no redshift, I used a question mark for that field.

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

Related Designations for NGC7132

NGC7137

NGC 7137 is a spiral galaxy in western Pegasus about 11 degrees north of M15. Redshift puts it 62 million light-years distant. A single Tully-Fisher estimate from 1988 puts it 82 million light-years away but has large error bars. It is classified as SAB(rs)c at NED while the NGC project just says S... whatever that means. Seligman says SBc? so there seems a slight difference of opinion about it. I'm not sure I even see it as barred. It is surrounded by a large faint, reddish halo of stars all papers seem to ignore that I saw. Using the redshift distance and including the halo, it is a bit over 40,000 light-years across. Some papers have said only 10 or 15 thousand. I don't know where they get that. Even if I use just the bright spiral section it is 18,000 light-years across by my measurement.

Being located in eastern Pegasus it isn't all that surprising to find some IFN in the image as I've found it in other images I've taken in this part of the sky. The brightest portion is to the northwestern corner of the image though fainter pieces are scattered elsewhere, mostly to the north. The galaxy was discovered by William Herschel on November 17, 1784, but didn't make either of the Herschel 400 observing programs for some reason. It certainly is bright enough at 13.0 magnitude and is very compact for a high surface brightness. Though it would be a challenge in an 8" scope. I've never looked for it visually which I find surprising.

NGC 7137 made it to my to-do list as a three-armed spiral according to a paper I saw. I looked at it in the POSS images and agreed. Since Arp had a category for 3 armed spirals but didn't include it I had to put it on the list. I never expected what I got. It has three arms, sort of, but each is very different. The one on the east is most typical but comes off of the core on a short side. That is, the core is oval east-west and it comes from above the north side of the core. If there's a bar it must run mostly east-west. The arm, however, is rather mottled with several star clusters. The arm on the west is shorter and comes from well below the south side of the core. In fact, the third arm starts between it and the core. The second arm, like the first, has hints of star clouds. The third arm however quickly breaks up into many star clouds, more than a dozen in fact. One paper came sort of close to describing what I saw when it says: "The disk is filled with arms which on one side break into six separate fragments; in contrast, there is but one major arm on the opposite side." I can't quite square that, especially the 6 fragments as I see over 12. This is one strange galaxy, even for a three-armed one. Stranger than the three he put into his atlas. But he worked from the POSS plates in many cases and those didn't begin to show how odd this one is. They make it look pretty typical and totally miss the large somewhat red halo around this blue galaxy. The bright portion is somewhat off center to the western side of the halo. I wonder if that indicates this odd structure of a flocculent galaxy with two rather normal arms is due to a merger in the recent past. Nothing I saw in any paper even hinted at this.

The blue galaxy 10 minutes nearly due west of NGC 7137 is UGC 11813, it is listed as being an Im: galaxy with a redshift distance of 69 million light-years so likely part of the group that NGC 7137 belongs to. No other galaxy in the image has redshift data so I didn't bother to prepare an annotated image.

This is my last August 2015 image. I'm finally moving to September images. I'm now only 3.5 months behind. I was 18 months behind a couple years ago. I'm catching up thanks to rotten imaging weather the last two years.

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

Related Designations for NGC7137

NGC7139

NGC 7139 is a planetary nebula in Cepheus, about 4000 light years away. Keep in mind that the distances to such nebula are quite uncertain. There are several different methods of estimating the distance to planetary nebulae and they rarely agree. It was discovered by William Herschel on November 5, 1787. It is in the second H400 program.

This planetary is a red ring around a blue center. In this case, we find the red light is from NII, singly ionized nitrogen (unionized nitrogen is NI). This glows with almost the same red color as HII (there is only about a 3 angstrom difference for those who are interested). So most HII filters, including mine, pass both making it hard to tell if you are seeing HII or NII. In many cases of planetary nebulae, it is NII that gives the red color. This is true of some very major planetary nebula like M27 as well. In this case the central star is rather old and has cooled to white-hot status and isn't all that blue in color. This lowers the amount of ultraviolet radiation. Close to the star, there is enough to cause OIII to glow with its characteristic blue color but that fades as you reach the outer parts of the nebula and there is no longer enough to cause oxygen to be doubly ionized. Nor is there enough to singly ionize Nitrogen without help. It turns out the star, when alive, had a strong solar wind that blew a hole in the interstellar medium. This is quite common, our sun is doing the same but to a lesser extent. That will change as our sun ages and its solar wind gets stronger. When the star "died" and sent off its outer shell through space it expanded unhindered by the interstellar gases thanks to this bubble, but it has now run into the edge of the bubble. Gases pile up creating a shock front. Energy from this and what reaches it from the central star are enough to cause the nitrogen to singly ionize with its characteristic red color. But it isn't sufficient to doubly ionize oxygen so we don't see the blue which would normally overwhelm NII emissions so the red NII emission defines the shock front where it meets the interstellar medium. While it likely is doing this in a full bubble we only see the red along the edges of the bubble where we see the most gas due to looking through the edges of the bubble. Though there is some evidence that gas is thrown off mostly from the equator of the star so it could be we are looking at this star right down its north or south pole and this is the edge of a disk or cylinder of material the star threw off. In other words, there is a lot about these nebulae we still don't understand! The blue parts of the nebula look washed out blue because there is a lot of HII emission mixed in with the OIII. Not enough to turn it red but enough to wash out the blue color, especially into blobs on either side of the central star.

14" LX200R @ f/10, L=4x10' RGB=1x10x3, STL-11000XM, Paramount ME

Related Designations for NGC7139

NGC7142

NGC 7142 is an open cluster in Cepheus that was discovered by William Herschel on October 18, 1794. It' isn't in either H400 program, WEBDA puts it at a distance of 5,500 light-years. The cluster is in the original Herschel 400 Observing Program. My entry from June 14, 1985, with my trusty Cave 10" f/5 under humidity cloaked skies at 60x reads: "Large, highly elongated cluster of mostly very faint stars. Over 50 stars seen though all but a dozen seem too faint for a 6" telescope, at least under my humid skies. I ran right over this faint cluster the first time I looked for it. It must be very difficult in a 6" telescope." Odd but I had a 6" f/4 at hand but never used it on the cluster, only surmised what I'd see in it. Can't find I ever looked for it in either of my 6" scopes (f/4 or f/12). WEBDA puts the age of the cluster at 1.9 million years with 0.4 magnitudes of reddening from galactic dust.

I found this one on the hard drive and can't find I ever ran it before. Probably because it is one of the first color images I took digitally taken using a beginner's poor technique. The result isn't very good even with a lot of reprocessing to try and save it. Another for the reshoot list as it is very photon starved with only 25 rather than my usual 40 to 50 minutes of luminance data using 5 minute rather than 10 minute subs increasing decreasing the signal to noise ratio due to read noise not being swamped by photon noise.

14" LX200R @ f/10, L=5x5' RGB=3x5', STL-11000XM, Paramount ME

Related Designations for NGC7142