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

NGC6633

NGC 6633 is an open cluster in Ophiuchus. WEBDA puts its distance at 1226 light years. They put its age at 426 million years while SEDS says 660 million years. This is one of the Herschel 400 objects which I'm imaging when nothing else is in position. This cluster is almost too big for my 33'x 22' field of view. It was discovered by Philippe Loys De Chéseaux in 1745 (maybe 1746). Caroline Herschel later made an independent rediscovery on July 31, 1783. While it is in the original H400 program he was the third to find it on July 30, 1788. My entry from May 20, 1985 on a good night at 65x with my 10" f/5 reads, "Large, scattered cluster of very bright stars most of which can be seen in binoculars. In fact, it is best seen in my 10x50 binoculars. Seems larger than the 20' usually stated for it."

This is in a very rich star field but a very sparse cluster. I had to greatly restrain the background stars limiting how deep this image goes. Otherwise, the cluster was lost in the Milky Way. The cluster contains only about 30 stars.

14" LX200R, L=3x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for NGC6633

NGC6636

NGC 6636 is a pair of galaxies in eastern Draco north of its head. The pair are located about 200 million light-years distant. The near edge on galaxy is classified as Sc with a Seyfert 2 nucleus at NED. Seligman says Sc? The companion to the east MCG +11-22-047 is listed as a compact galaxy at NED and Sab? by Seligman. A note at NED says this about the companion: "Dwarf satellite connected to the primary by a short thin filament, mostly normal to the surface of the latter. Primary appears to be spheroidal, not spiral. VV 368 relates to the companion on a stem (at the left). On the list 45 VV 679 relates to the whole group." I'd translate this if I could but I think I'd need a few (many?) more shots to do so (booze not image frames). VV 679 is both galaxies while VV 368 refers only to the edge on galaxy according to NED but the comment seems to say it is the dwarf. I don't know where the "companion on a stem" comes from unless it is the blue apparently distant galaxy above the compact galaxy. The thin filament connecting the two is somewhat of a mystery as well. "Normal" usually means perpendicular. The only thing I see this may refer to is the blue arc under the compact galaxy. It is sort of normal to the edge on if an arc is allowed to be used this way. Other sources also refer to the compact being "attached" to the edge on. I'm afraid I don't see that. The comment that the primary appears to be spheroidal again is saying the dwarf is the primary? The whole thing makes no sense to me. It seems all backwards.

NGC 6636 appears to be a quite interesting spiral if we could see it more face on. It seems to have two major arms that are widely drawn out with lots of star clouds. I assume the length is partly due to interaction with the compact galaxy. I measure it at about 115,000 light-years across with the compact companion being only 15,000 light-years across. Normally such a small galaxy would be torn up by its much larger companion. Its very high density apparently saved it from this fate though outer stars likely were lost in the encounter. Now the blue arc below it fits in I don't know.

Then there's the odd blue object above the compact. It doesn't appear related though may be the "stem" referred to in the note. I find nothing in any catalog that corresponds to it. I assume it is some very blue distant galaxy unrelated to these two but that's only speculation on my part. NGC 6636 was discovered by Albert Marth on July 9, 1863.

Being so far north it is in an area of the sky poorly surveyed. Only a red starlike galaxy 6.4 minutes northeast of NGC 6636 had redshift data putting it 1.15 billion light-years away and it is near the center of what is listed as a galaxy cluster at the same distance though no count of galaxies in it is given. There is a similar blue starlike galaxy below it without any data. Otherwise, I see nothing that could be part of the cluster. With so little, I didn't prepare an annotated image. At least this time I didn't lose a frame, green or otherwise to sky conditions as has been the norm this summer thanks to fires out west as well as cloudy weather.

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

Related Designations for NGC6636

NGC6643

NGC 6643 is a nearby spiral galaxy in Draco about 65 million light-years by redshift. I put it on my to-do list because it is giving us the finger in the form of a spiral arm that sticks out at an odd angle. It is a very blue spiral classed as SA(rs)c by NED. The blue color indicates much of its light comes from newly minted massive blue stars. Notes at NED indicate there are extensive H alpha regions outlining the spiral arms. They don't show in my LRGB image, however. Though the blue star clusters forming in them do show as blue knots that give the galaxy most of its spiral structure. Except for the odd rather straight arm to the southwest, its spiral arms are rather weak being overpowered by the star clusters along the arms. What triggered this massive star formation apparently isn't known. At least I was unable to find anything on this. It lacks any close by companions. It was discovered by Eduard Schönfeld in 1858. The exact date is unknown. Horace Tuttle then discovered it independently on September 1, 1859.

To the northeast (upper left) of NGC 6643 is 2MASX J18212063+7438188. It has a rather strong but small core surrounded by a very faint, face on disk. I needed a lot more time to see any detail in this faint ghost disk. Where'd its stars go? Have they died or just not yet been born? It's a very strange object. Some star formation must be going on someplace in it, core most likely, as this is usually a requirement to create the IR light seen in the 2MASS survey.

I found little information on this area of the sky. NED only lists 8 galaxies, including NGC 6643 in the field. All 8 are from the 2MASS survey of IR emitting galaxies. The only other galaxy of any angular size in the image beside NGC 6643 and the "ghost" galaxy is the very blue smudge to the north-northeast. While it too is blue, star formation has apparently slowed in it as it isn't in the 2MASS survey or any catalog at NED. It seems to be anonymous as are the vast majority of the background galaxies.

There appears to be a distant galaxy cluster near the left edge of my image a bit above center near a close white pair of stars. I found nothing on it, however.

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

Related Designations for NGC6643

NGC6654

NGC 6654 is a rather strange galaxy in Draco. It's distance isn't well known. Redshift puts it at about 80 million light-years distant though a single Tully measurement says 96 million. Assuming the 80 million light-year distance it is about 63,000 light-years in diameter. NED classifies it as (R')SB(s)0/a while others say simply SB0 or something in-between. In any case, all see it as a barred galaxy. One paper even says it has two bars the obvious one and a much smaller inner one at a somewhat different angle. Oddly my image, however, sees it not as a bar at all but an inner "Saturn-like" ring rather than a bar. I find few images on the net to help here. The disk shows a faint spiral structure with an odd dark area to the northwest. It was that odd gap that caused me to put it on the to-do list. The galaxy was discovered by Lewis Swift on September 11, 1883.

There's little on the field this far north. Only a quasar has any redshift data besides NGC 6654. Little else is identified at NED. I have noted everything they have listed as a galaxy or has a redshift even though they don't have distance data. Hundreds of Ultraviolet Excess objects are listed, most of which are blue stars. I didn't wade through these to find which were galaxies. Though a test showed most, not all, of the obvious galaxies without an annotation were listed as being an UvS rather than a galaxy at NED. Since none had redshifts I didn't both to note them as it would be a difficult chore to separate them from the stars. Also, their error bar for positions is over 5' of arc meaning many overlap making it hard to tell what is what. I wanted to know more about the blue object in the northern halo of PGC 061821. But it wasn't listed in NED. It doesn't appear to be a star and doesn't have the PSF to be a blue quasar. Could that rather small galaxy have a huge blue star cluster? That's about all I can come up with.

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

Related Designations for NGC6654