NGC6491

UGC 11007 is a mostly one-armed spiral in Draco. Its distance is unknown. While it shares the field with two NGC galaxies they appear far closer leaving the mystery of UGC 11007's odd shape unanswered. It is classed as simply as SB, no peculiar designation.

The two NGC galaxies are also interesting. NGC 6491 is classed as Sab. NED has two redshift measurements for it. The main one they prefer says it is about 240 million light-years distant while the other says 280 million light-years. As such measurements go this isn't a major difference at all. It is a very red spiral. I'd have suspected a bar with the elongated core and red color (red spirals tend to be barred). It has a blue plume of recent star formation that really stands out against the rather bland galaxy. Was that triggered by NGC 6493?

NED has only one redshift for NGC 6493 that puts it at about 268 million light-years, between the two for NGC 6491 but closer to the less accepted value. Again these differences could reflect random motion differences. It is classed SAB(r)cd. While blue it isn't as blue as many of its type. Its arm structure is rather nonsymmetric. This could be natural or possibly indicate interaction with some other galaxy in the past. Flip a coin. In any case, this is an interesting group.

NGC 6491 and NGC 6493 were discovered by Lewis Swift but on different nights. He found NGC 6491 on June 13, 1885 and NGC 6493 on June 5, 1885.

There's redshift data for only one other galaxy in the field. Draw a line from NGC 6493 through UGC 11007 and continue on a bit less than twice that distance and go up slightly. You come to VII Zw 747 described as a "blue large knotty disc compact". It is listed at about 525 million light-years distant so definitely unrelated to the NGC galaxies.

Another galaxy caught my eye. It is nearly directly above NGC 6491, two-thirds of the way to the top of my image. It looks like a comet with a short curving dust tail going up and to the right. At the end of the "dust tail" is a very faint galaxy (7 o'clock from an orange star). That faint, star-like galaxy is SDSS J175000.63+614047.9 at magnitude 21.6. I mention it only because the far brighter and larger comet-like galaxy isn't listed at NED at all! Yes, it is a galaxy as I found it on the POSS plates. These interesting but uncatalogued galaxies drive my brain nuts. Why are the far fainter ones listed but these odd ones are sometimes missing? There's another comet like galaxy in the image. This one is above and a bit left of UGC 11007 in the cropped and enlarged image. It too isn't in NED. They don't seem to like comet-like galaxies it would appear. Again some far fainter ones are listed.

Arp was fond of saying that all galaxies are peculiar if you look close enough. This field would seem to support that idea.

14" LX200R @ f/10, L=4x10' R=3x10'x3 GB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for NGC6491

NGC6495

This field is in southeastern Hercules too close to the Zone of Avoidance for Sloan or other surveys that provide distance data to cover. It has 3 NGC galaxies; NGC 6495 (barely), NGC 6500 and NGC 6501. All are about 140 million light-years distant by redshift as is PGC 061102. Most sources consider NGC 6500 and NGC 6501 as interacting. NGC 6500 has a strong outflow according to most papers. That may be the cause of the faint eastern arm though I didn't find any confirmation of that. It could be just due to NGC 6501. Notice that while all agree quite well with similar redshift distance data their non-redshift distances are widely off for NGC 6500 and NGC 6501. NGC 6495 agrees nicely, however. I don't know why the difference.

This image was taken in the height of smoke from Canadian fires in Manitoba and British Columbia plus some from the California fires. The smoke wiped blue almost entirely, severely hurt green such that even with eXcalibrator color was awful. Seems the smoke was very different in density with some areas of even this small field hit hard and other areas not so much. The result was a super gaudy image with super reds and super blues depending on the smoke as Excalibrator matches the entire field not individual stars or locations. Trying to find color images of this field taken without smoke resulted in those made from DSS red and blue plates being way too blue to the one amateur color image I found from Japan showing the field as very red. Seligman has a photo taken from an uncredited source that is closer to what I suspect is correct. I tried to adjust my color to its colors by isolating many different areas and adjusting as needed. I normally totally avoid any color adjustment that isn't global but had to break a hard and fast rule (never broken before that I can recall) to get this to looks at all reasonable. Normally the background of my blue images is about 400 with green at about 410 and red at 420 but with the normal exposure blue was 102, green 112 and red 121. That's how hard it was hit by the smoke. Brighter regions were hit very differently than the background making this one a nightmare to process. After three days of struggle, I have given up and am going with this. Since the field isn't all that exciting I likely won't try again.

NGC 6495 was discovered by Albert Marth on May 11, 1864. NGC 6500 and NGC 6501 were discovered by William Herschel on June 29, 1799. Since most of his deep sky work was prior to 1790 this was one of his last finds though he continued rarely to 1802. He died August 25, 1822, doing mostly double star work after about 1802. Even that was intermittent. Why I don't know. If anyone does please let me know. Neither NGC 6500 or NGC6501 are in the Herschel observing programs. I left no comment as to why I imaged this field. Usually, I take these only because they are in one or the other of the observing programs. I put in on the list years ago at a low priority so it just now was taken, long after I forgot why.

Smoke is still a pain and even worse than when this was taken. Last night the cloud sensor and IR images showed no clouds with a great sky. Using the Telrad on the 14" I was able to point the scope at Vega and then barely see Vega. I'd not have found it otherwise. That's how thick the smoke was. Local hospitals are overrun with folk who never had breathing issues to the extent they can't begin to keep up a who is not in that field but all were pressed into service. Local pharmacy had about 50 waiting to get prescriptions. It doesn't bother me nor my wife but sure is most everyone else. We have air conditioning which is rather rare here so that may be the difference.

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

Rick

Related Designations for NGC6495

NGC6503

NGC 6503 is a nice flocculent galaxy in eastern Draco and thought to be about 17 million light-years distant based on HST images of its red giant stars. Most sources call it a dwarf though NED doesn't. Nor should it in my opinion. Most sources give its diameter at 30 million light-years. I find that quite wrong. That is the diameter of its brighter disk but the disk extends considerably further both directions in my data. I find it nearly 10 minutes of arc across which makes it 49,000 light-years across. The faint extensions appear full of fuzzy objects. Since the HST image doesn't begin to go out far enough I don't know what these may be. Likely star clusters I would think. Some may be globulars I suppose but they seem to be in the disk making that unlikely. This is a very active galaxy with an active core and many star-forming HII regions. It was discovered on July 22, 1854 by Georg Friedrich Julius Arthur von Auwers using a 6.2" telescope.

The galaxy is on the edge of the "Local Void". This is a very poorly defined region bounded by our local group, the Hercules Cluster and some say the Coma Cluster. I have trouble with the latter as that is about half a billion light-years out so not exactly "local". The size of the void is given as somewhat between 30 and more than 150 million light-years. I'd say that is rather vague and rather a rather useless description. The void is said to contain fewer galaxies than would be expected there but with such a poor boundary I'd think you could "prove" about any density you wanted by playing with such a vague volume.

Being above (barely) the 70-degree limit I had for years I was unable to catch it. I wanted to try and see those HII regions. Finally, after my two Polaris trees had to be removed before they fell on the house or observatory I got the data. But not the HII data I had apparently planned on. The result was it was removed from my to-do list but not added to the to-process list though the data files had been moved into that directory. Without going on the listing it sat there ignored. After a request was put out for the image some time ago I looked and saw the data was waiting to be processed but never noticed it wasn't in the queue to actually be processed. I mentioned I had the data but it would be a while before I got to it as I looked down the listing for two months and didn't see it. Finally, I wondered when I would get to it so looked down the full list and it wasn't there. So years late I finally made a rush to process the data even though there's no H alpha data. Apparently, I was planning on getting that but not putting it in the to-do queue at all let alone at a high priority that never happened. If the weather ever clears here I'll see if I can remedy that.

Also, I found the red data was poor. It got hit by clouds and hurt badly. That I noticed and I retook the data or tried to later that night after it cleared. But instead of taking red data I took blue! This one just wasn't meant to be. I struggled but think I sort of salvaged the color even with this handicap.

There's not much on this field. Some of the obvious galaxies are strong Ultraviolet emitters and were cataloged by the GALEX ultraviolet space telescope. Oddly NED picks them up only as UV sources of an unknown nature rather than as the galaxy they are. None have redshift data so I didn't note them on the annotated image. I did note all galaxies NED listed as galaxies, however. Since these are only known by their coordinates I didn't bother to identify them beyond their status as G for galaxy AGN for active galactic nucleus and Q for quasar. Somehow three from the 2MASS survey without distance info did get fully identified. Why I don't know. I'm dead tired after two hard days splitting many cords of super heavy oak. That's my excuse and I'm sticking to it. I'm too old to be lifting 100 lb. hunks onto a splitter. I need one with a hydraulic lift. Some are over 30" across.

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

RickNGC 6503 is a nice flocculent galaxy in eastern Draco and thought to be about 17 million light-years distant based on HST images of its red giant stars. Most sources call it a dwarf though NED doesn't. Nor should it in my opinion. Most sources give its diameter at 30 million light-years. I find that quite wrong. That is the diameter of its brighter disk but the disk extends considerably further both directions in my data. I find it nearly 10 minutes of arc across which makes it 49,000 light-years across. The faint extensions appear full of fuzzy objects. Since the HST image doesn't begin to go out far enough I don't know what these may be. Likely star clusters I would think. Some may be globulars I suppose but they seem to be in the disk making that unlikely. This is a very active galaxy with an active core and many star-forming HII regions. It was discovered on July 22, 1854 by Georg Friedrich Julius Arthur von Auwers using a 6.2" telescope.

The galaxy is on the edge of the "Local Void". This is a very poorly defined region bounded by our local group, the Hercules Cluster and some say the Coma Cluster. I have trouble with the latter as that is about half a billion light-years out so not exactly "local". The size of the void is given as somewhat between 30 and more than 150 million light-years. I'd say that is rather vague and rather a rather useless description. The void is said to contain fewer galaxies than would be expected there but with such a poor boundary I'd think you could "prove" about any density you wanted by playing with such a vague volume.

Being above (barely) the 70-degree limit I had for years I was unable to catch it. I wanted to try and see those HII regions. Finally, after my two Polaris trees had to be removed before they fell on the house or observatory I got the data. But not the HII data I had apparently planned on. The result was it was removed from my to-do list but not added to the to-process list though the data files had been moved into that directory. Without going on the listing it sat there ignored. After a request was put out for the image some time ago I looked and saw the data was waiting to be processed but never noticed it wasn't in the queue to actually be processed. I mentioned I had the data but it would be a while before I got to it as I looked down the listing for two months and didn't see it. Finally, I wondered when I would get to it so looked down the full list and it wasn't there. So years late I finally made a rush to process the data even though there's no H alpha data. Apparently, I was planning on getting that but not putting it in the to-do queue at all let alone at a high priority that never happened. If the weather ever clears here I'll see if I can remedy that.

Also, I found the red data was poor. It got hit by clouds and hurt badly. That I noticed and I retook the data or tried to later that night after it cleared. But instead of taking red data I took blue! This one just wasn't meant to be. I struggled but think I sort of salvaged the color even with this handicap.

There's not much on this field. Some of the obvious galaxies are strong Ultraviolet emitters and were cataloged by the GALEX ultraviolet space telescope. Oddly NED picks them up only as UV sources of an unknown nature rather than as the galaxy they are. None have redshift data so I didn't note them on the annotated image. I did note all galaxies NED listed as galaxies, however. Since these are only known by their coordinates I didn't bother to identify them beyond their status as G for galaxy AGN for active galactic nucleus and Q for quasar. Somehow three from the 2MASS survey without distance info did get fully identified. Why I don't know. I'm dead tired after two hard days splitting many cords of super heavy oak. That's my excuse and I'm sticking to it. I'm too old to be lifting 100 lb. hunks onto a splitter. I need one with a hydraulic lift. Some are over 30" across.

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

Rick

Related Designations for NGC6503

NGC6504

This is another early image when I wasn't writing much on the image or researching it. Below is what little I did have to say about it on a small list of friends I sent it to. I'll just add that it was discovered by Albert Marth on July 27, 1864. NED classifies it as S while Seligman says S??. It is located in Hercules.

Do you believe in flying saucers? No? Are you sure? Years ago this lake was listed in a highly touted book as one of the top 100 walleye lakes in Minnesota. Problem is they are as elusive as flying saucers. You meet folks whose neighbor knows a guy whose wife's brother caught one. I always said I'd believe in flying saucers when one landed in my yard and I'd believe in Mantrap walleye when I caught one. Then about 20 years ago I did catch one, one in 60 years of fishing this lake! Still, I now check my yard for flying saucers now and then. Seems the other night I caught one. At least it sure looks like one.

It's a bit too large to land in my backyard as it is a bit over 100,000 light-years across. Nor is it unidentified, being well known as NGC 6504, a galaxy a bit over 200 million light years from us and about the same size as our galaxy. So now I've seen something that looks like a flying saucer from my yard. It can be seen from any yard in the northern hemisphere and some in the southern as it is "flying" through the constellation of Hercules. There may even be aliens in the image. If so they are a bit below my resolution level!

14" LX200R @ f/10, L=4x10' RGB=1x10'X3, STL=11000XM, Paramount ME

Related Designations for NGC6504

NGC6517

NGC 6517 is a globular cluster in Ophiuchus about 35,000 light-years distant and about 14,000 light-years from the galaxy's core. Judging by the red star color I assume the area is highly reddened by dust though I didn't find by how much. Its diameter is listed at 4.1 minutes of arc. Using that and the above distance it would be about 42 light-years in diameter. It is listed as class IV. Type I is most condensed and XII the least. For comparison, M13 is class V so less condensed. It certainly doesn't look very condensed in my image. That's because I altered reality. With a standard stretch, the core was saturated showing it was quite dense. But I saw hints of detail so I retarded the stretch of the core region. This brought out three dust blobs near the core I've not seen in any published image of the cluster. I don't know if they are in the cluster or between us and the cluster. This is a very dusty region of our galaxy we look through to see this cluster.

The cluster was discovered by William Herschel on June 16, 1784 and is in the first Herschel 400 observing program. My log from that for the night of May 20, 1985 using my 10" f/5 on a good night at 120x reads: "Small, faint, unresolved globular, gradually brighter toward the center." Reports by Steve Gottlieb for the NGC Project using a 17.5" Dob says: "fairly faint, small, irregularly round. 2' diameter, No resolution at 280x." So even with a much larger scope, no stars were seen. I'd have suspected those two-star trails might show but apparently not. Notice in my image the cluster is quite lopsided to the east. There's quite a halo of faint stars to the west. The core is where you see a tight group of stars just left of the three dust balls. Well east of the cluster's center but rather well centered in the brightest part of the cluster. I don't recall any other cluster in which this occurs.

Being in such a heavily obscured part of the sky nothing else of interest is in the image so I didn't prepare an annotated version.

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

Related Designations for NGC6517

NGC6535

NGC 6535 is a rather obscure globular star cluster in Serpens Cauda. It is located about 22,200 light-years from earth but only 12,700 light-years from the center of the galaxy. Globular clusters orbit our galaxy in mostly highly elliptical galaxy spending most of the lives far from the center of the galaxy. But NGC 6535 is currently in the part of its orbit that carries it into the region of the galaxy's core. It is classed class XI on a scale in which type I is most condensed and XII least concentrated. One as loose as NGC 6535 could be mistaken for a dense open cluster such as M 11. The cluster was discovered by John Hind on April 26, 1852 using a 7" refractor. He only found 4 NGC objects but one of them is NGC 1555 Hind's Variable Nebula.

NGC 6535 is an object I didn't have on my to-do list. On this night I opened the observatory while it was still a bit light. When the scope wakes up it goes to its "home" position which is an arbitrary point approximately two hours west of the meridian and nearly on the celestial equator. That night I took a preliminary image to see if all was working. There at the top of the image (south up) was a smudge in a 5 second exposure. Checking I saw it was this globular cluster. Looking it up I found virtually no images of it so decided to spend the 70 minutes on it even though it was well outside my image zone of good seeing. While seeing for this image is about 3.2" to 3.5" it came out surprisingly well. At least it is colorful.

Only a couple of galaxies in the image had redshift values. CGCG 028-004 is the quite red elliptical galaxy to the west (right) of NGC 6535. It is about 330 million light-years distant. Near the right edge, a bit below centerline is CGMW 3-1363 is listed as a spiral at 320 million light-years. None of the other faint fuzzies have distance data at NED at least.

Since it is seen against the Milky Way it is in a very rich star field which really blows up the size of a JPG image.

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

Related Designations for NGC6535

NGC6543

NGC 6543, the Cat's Eye Nebula is located in Draco about 3000 light years from earth. It is a small planetary nebula about 27"x 24" of arc in size for the bright center area. The outer parts are 350 x 332 seconds across in my image. While often imaged by the Hubble Space Telescope none of the images are true color. The closest I've found is at http://www.nasa.gov/multimedia/imagegallery/image_feature_211.html. The outer regions are far too large for this telescope so it only shows the core region.

The outer parts are not really part of the planetary nebula itself. That is the bright central part. The outer parts are dust and gas thrown off by the central star while still a red giant during its mass loss stage prior to it creating the planetary nebula. The ages of planetary nebula are hard to determine but models indicate they can't last much more than 10,000 years but the expansion rate of the faint outer part indicates it is at least 50,000 and maybe as much as 90,000 years old. The spiral galaxy is NGC 6552 at about 350 million light-years. It is classed as SB? at NED and SBbc by the NGC project. It is a strong X-ray source and a Seyfert 2 galaxy so has a very active nucleus. Its colors seem strange. The bar is blue but the ring like arms very red. Or is it a bar? Take away the ring and it would look like a disk galaxy that has lost its dust but blue from recent star formation. I found little on this guy but could it be the result of a merger of a spiral and an old elliptical galaxy? That could explain the active nucleus.

NGC 6543 was found by William Herschel on February 15, 1786. My log from the original H400 preliminary list using my 10" f/5 on a good night at up to 180x reads, Small, blue oval, planetary nebula. No central star seen, A very easy object." Of course, I was seeing only the planetary part of the nebula complex and had no idea it isn't "easy" to image. I had done so with film but that didn't pick up the area beyond the planetary either.

The Cat's eye Nebula is a very difficult target due to the extreme range in brightness. I didn't begin to get enough time on it for the outer parts. The inner part is so bright I could use only 1 minute exposures. Due to my camera's high read noise compared to some other cameras I took 60 of them. 3 were discarded due to seeing being suddenly worse on them than the rest. Why I don't know as they were not consecutive images. I then used an hours worth, in 10 minute subs, of data for the outer parts. That turned out to be insufficient. I really need at least two hours worth at 20 minutes per sub to be sky limited when imaging at 1x1 binning as I did here. So the outer regions are noisy and very fuzzy. I'll have to try again if I ever get a night for 1x1 binning again. Merging the two turned out to be more difficult than I expected. I really needed to get some 4 minute subs to transition between the inner and outer regions.

14" LX200R @ f/10, Core L=57x1'x1 RGB=10x1'x2, Everything else L=6x10'x1, RGB=2x10'x2, STL-11000XM, Paramount ME

Related Designations for NGC6543

NGC6548

New math: 3 NGC objects + 2 galaxies = total confusion plus a loaf of sliced French bread. I should have known I was headed for confusion when I looked up NGC 6548, a galaxy on the H400 II observing program, in NED and was directed to the southwestern of a pair of galaxies. But The Sky went to the northeastern brighter one. Confused when I noticed the coordinates of the northeastern one matched the H400 II coordinates I went ahead and took the field. It wasn't until I processed the image and started in on my research that I saw what a can of worms I'd run into.

The northern galaxy's an SB0 galaxy with a huge halo. It is a bit under 100 million light-years from us by redshift. Non-redshift measurements range from 125 to 174 million light-years. Using the redshift distance it is about 75 thousand light-years in diameter including the huge featureless halo. It is in the Herschel II observing program as NGC 6549. This is what the NGC project calls it as well but other sources list it as NGC 6548 and or NGC 6550 so depending on who you believe it is one of those three. William Herschel discovered it on September 20, 1786. Though he got the coordinates slightly wrong there's little doubt this is the galaxy he discovered.

The galaxy to the southwest makes a nice pair but they are an optical, light of sight, pair rather than being a related pair. It is 290 million light-years distant by redshift and between 75 and 280 million miles from us by non-redshift measurements. Using the redshift measurement it is a very large galaxy with a diameter of 130,000 light-years. It is classified as S?. It was discovered on July 27, 1864 by Albert Marth who gave accurate coordinates and on July 18m 1882 by Edouard Stephan who gave coordinates that leave no doubt this is the galaxy he saw but he also referred to a third object (he mentions Herschel's galaxy as the second). There is no third galaxy he might be referring to. Many have settled on the line of three equally bright stars east of the lower galaxy. The coordinates are too vague to know for sure. It was given the third NGC number of NGC 6550. Herschel's galaxy was given the NGC 6548 number since it was found first even though it didn't match the normal order of right ascension and Marth's galaxy NGC 6549. At this point, all was well in the world order. Then Lewis Swift came along and due more to a vague comment he made caused mass confusion. Since NGC 6550 didn't exist some were saying it was a double of Herschel's galaxy. Swift was trying to say it couldn't be because Stephan specifically mentions it. But somehow his remark was interpreted as saying NGC 6550 it was Herschel's galaxy, exactly what he was trying to say wasn't true. Others reading the remark right assigned 6550 to the southern galaxy and NGC 6549 to Herschel's galaxy. I can't follow all this logically but this is basically what Dr. Corwin of the NGC Project and Dr. Seligman are saying. Others have different interpretations that I found even harder to follow. Here's the result referring to the galaxies as the northern and southern one by source

Northern Galaxy
NED says it is 6550
Simbad, The Sky 6 and HyperLeda say it is both 6548 and 6550
The NGC Project, Herschel II observing list and Seligman say it is 6548
There is an HST image of its core taken in UV light that labels it 6550


Southern Galaxy
NED and HyperLeda say it is 6548 and 6549
Simbad and The Sky 6 say it is 6549
NGC Project and Seligman say it is both 6549 and 6550
So all three numbers apply to this galaxy depending on the source.

Since these are the only two galaxies with redshift data (with three NGC identifications) in the image and there are no asteroids in it I'll avoid voting on who is right by not preparing an annotated image.

Now to see if there's any Jack Daniels left in the bottle.

But do take a close look at the southern galaxy. It is awfully strange. Something that has mostly gotten lost in all the to-do about which NGC number belongs to which galaxy. It has two strange features. One that does get mentioned is the object on its southeastern side that juts out. Is it a jet or separate galaxy. Since this field is in the Zone of Avoidance it isn't covered by the Sloan survey. I found papers asking this question but none answering it. Unable to find a single image with better resolution than mine (hey you guys with better seeing than I have you may be able to answer this question) I'll say to me it appears to be a separate galaxy but higher resolution may say otherwise. The other strange feature is the diagonal dark lanes that divide the galaxies length into 5 segments much like you might cut up a loaf of French bread. They appear virtually parallel to each other and divide it into somewhat equal segments but for the larger middle one. They seem to start from what appears to be an equatorial dust lane along the northwest side of the galaxy. The odd jet-like feature seems to spring from one of these lines. Coincidence? Probably.

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

Related Designations for NGC6548

NGC6621

Arp 81 is NGC 6621 and NGC 6622. Arp put it in his category of spirals with large, high surface brightness companions. While many he considered companions are now known just to be line of sight galaxies that are unrelated. That's not the case here. This pair is located in Draco about 280 million light-years distant. The small southern galaxy is NGC 6621. It is classified as Sa by NED, Sbc by the NGC project and (R)SBa? pec by Seligman. It is thought to be orbiting NGC 6622 and has dawn out the large plume running around NGC 6622. It was discovered by Lewis Swift on June 2, 1885.

NGC 6622 is the large galaxy with the huge plume drawn out by NGC 6621. It is classed as Sb: pec HII;LIRG by NED, Sb/P by the NGC Project and Sb? pec by Seligman. It was discovered by Lewis Swift the same night as he found NGC 6621.

The Hubble Space Telescope has studied this pair. Rather than retype it here's the link: http://www.astr.ua.edu/gifimages/ngc6621.html . For those wanting a deeper discussion see: http://arxiv.org/PS_cache/astro-ph/pdf/0309/0309674v1.pdf .

14" LX200R @ f/10, L=5x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for NGC6621

NGC6632

NGC 6632 is a rather peculiar galaxy in Hercules about 210 million light-years distant per its redshift measurement. It is classed as SA(rs)bc at NED, simply as Sb by the NGC project and several other sources. I consider it an Arp-like galaxy due to the odd southern arm that appears rather disrupted by some tidal effect. It looks severely warped as well. Though this might be an illusion. The source of this is hard to determine, however. To its southwest is the very weird galaxy 2MASX J18245534+2730302. It has a rather odd blue core at its north end and a rather red plume going south from it so looks quite comet-like. It is best seen in the enlarged, cropped image. No other galaxy but for NGC 6632 in the image has a redshift measurement that I found at NED. So we can't tell if 2MASX J18245534+2730302 is at the same distance as NGC 6632 or not. If it is, it's odd distortion would make it a likely candidate for what tore up NGC 6632's southern arm.

Another oddity is the color of the galaxy. Overall it is rather red. Very few hot blue stars are seen in it. Usually, a tidally disrupted galaxy has a lot of star formation going on and thus has some really blue stars. That doesn't seem to be the case here. At first, I thought something went wrong with my color balance but any attempt to change the color of the galaxy to classic spiral colors resulted in the star colors getting well out of whack. Most amateur color images show more normal coloration though a professional image and one amateur one comes up with colors much like mine. I do need to revisit this one just to be sure something didn't screw up the color. It was discovered by Albert Marth on June 24, 1864.

With no redshift data, I didn't prepare an annotated image.

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

Related Designations for NGC6632