NGC6871

NGC 6871 is a very large young cluster in Cygnus about 5000 light-years distant. WEBDA gives its age as about 9 million years. I moved the cluster to the side to pick up the dark lane in the background nebulosity. I shouldn't have done so as there seems to be an interesting red filament coming in from the left side of the image besides the vertical one. I knew about the vertical one but not the other one. In fact, I spent some time trying to figure out where that "reflection" came from before seeing it is clearly seen on the DSS red plate. It was discovered by William Herschel on September 23, 1783.

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

Related Designations for NGC6871

NGC6882

NGC 6882/6885 is a star group in Vulpecula. It may be made up of several groups. WEBDA has nothing on it but a position. It is Trumpler class III2p so little to no concentration, made up of stars covering a wide brightness range and star poor. I find no distance for it or much of anything in fact. It carries two NGC numbers since it was found by William Herschel on two consecutive nights. September 9, 1784 and September 10, 1784. There's nothing of interest at the position of NGC 6882 but there is for NGC 6885. The position for 6882 lies at a bare region within 6885. To me, the cluster is made up of several groups as mentioned above and it may be Herschel saw one of these groups as 6882 but got the position wrong. He got several other objects positions wrong that night. As Dr. Corwin says "WH was clearly not up to snuff that night..." I've had too many of those nights so I'll cut William some slack here.

The first Herschel 400 lists both clusters as two separate objects. This confused me to no end it appears from my notes from May 20, 1985. I wrote of NGC 6885 as seen in my 10" f/5 scope: "Large scattered, open cluster of stars of all magnitudes. Mostly west of 20 Vulpecula (that's the bright blue star in my image). Dimmer stars seem to be centered about 4' north and more condensed than the very widely scattered brighter stars. This may account for its two numbers in both catalogs. Dim stars center is about that of 6882." My comments for 6882 written at the same time read: "See 6885 as I was unable to distinguish a second cluster anywhere in the area. 6885 is listed as 20' across and this one only 4' north so inside the other. Burnham, the Becvar catalog and Tiron make no mention of this object! Why not pick another Herschel object to replace this one -- say H-14-5 which is the bright arc of the Veil complex?" I'd forgotten all about this until I went to research this object after processing it.

I had to move the cluster low in the field. 20 Vulpeculae was sending horrid ghosts across the frame when placed higher in the field. Why moving it slightly south solved them I never did figure out. There are three rather bright stars just out of the frame to the north. They sent some nasty gradients into the frame as by moving the field south they almost came into frame. Fortunately, GradientXTerminator pretty much eliminated the problem.

As mentioned I couldn't find any distance for the cluster. Three of the brighter stars have Hipparcos data in The Sky which put them only about 120 light-years distant. 20 Vulpeculae is 10 times that at 1,140 light-years.

The weather was a problem while imaging this one. I had to sort through several nights of images to find those used here. Only one green image survived the cut as all others were lost to haze and clouds. Fortunately, the one had no satellite and I was able to make it do.

14" LX200R @ f/10, L=4x10' RB=2x10' G=1x10', STL-11000XM, Paramount ME

Related Designations for NGC6882

NGC6883

This field is in Cygnus a bit east of the neck of the swan. It is in H alpha emission that dominates along the axis of the Milky Way in this constellation. Here it is quite weak and I needed to use the H alpha filter to pick it up but the weather has been so bad that couldn't happen.

There is a lot going on in this field but unfortunately, I couldn't find much on what I show. NGC 6883 itself is confusing. Most catalogs give its location as that of the double star a bit below center in my image. To the upper right, is what appears to be another star cluster but it isn't in any catalog. Then I found catalogs that show the size of NGC 6883 sufficient to cover most of this field. WEBDA doesn't list any detail for it though does give its coordinates and a photo that includes much of my image but not the nebulae to the far left. I can't tell if they consider it an asterism or cluster. I suspect asterism but that's just a guess.

Below the double star at its usual coordinates is a dark nebula with 3 stars in it. That isn't in any catalog I checked. To the upper left is an area with two reflection nebulae and a dark nebula below the brighter reflection nebula. I did find the smaller reflection nebulae in SIMBAD. They list it as GN 20.10.7. It is centered on the apparent illuminating star. I find nothing on the bright nebula though some sources seem to consider the whole area with the name. But list it only as a reflection nebula so must not include the dark nebula. Just to the east of the star illuminating GN 2.10.7 is a smaller reflection nebula around a fainter star. It is[B77] 20. It is listed as a bright nebula so again misses the dark nebula. Some catalogs seem to include both under the GN 20.10.7 designation. The large reflection nebula isn't in any catalog I looked at. Simbad lists the illuminating star as an emission line star but otherwise is silent about the nebula. It too may be part of GN 20.10.7 though that is nearly centered on another reflection nebula sort of discounts that idea.

Due to issues with lots of clouds, especially during the red filter portion, the nebulosity barely shows and is a rather odd color. I processed for the star's color and let the faint emission nebula in the background to fall where it did. I need to do this one on a better (smokeless) night but that's not happening. Between Canadian fire smoke (limiting some nights to only seeing Vega through it) and clouds, the rest of the time that you can't tell from smoke visually though my cloud sensor can as the IR signature of clouds is very different from smoke -- which the sensor is blind to in fact. So I know both are involved as the clouds aren't thick enough to kill all stars but Vega. I'd expect the smoke to kill blue and let red through but the reverse seems true here or else in balancing star color for the smoke I killed red. The histogram for this one looks awful. I think the smoke is to blame. I need to try this another year without the horrid smoke. As I write this we are under a 4 day air quality alert due to the smoke at the highest alert level. Manitoba must have it even worse. We are also seeing a bit of smoke from British Columbia fires and the California fires.

The cluster or asterism was discovered by William Herschel on August 19, 1828. I didn't expect any of the other bright or dark nebulae when I took the image. I have no idea why I took this image. It isn't in either H400 program nor do I find it on my to-do list the computer looks to for targets. I had to have interrupted the computer and entered it manually. Was I trying to avoid the lousy weather and it was in a hole? I have no idea.

14" LX 200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick

Related Designations for NGC6883

NGC6888

NGC 6888 is a bubble blown by a Wolf-Rayet star in Cygnus. It was discovered by William Herschel on September 15, 1792. It is in the second H400 observing program. It may be about 5000 light-years distant. Seligman has a good write-up on this one so I'll save my fingers and paste in his words.

"The Crescent Nebula is an emission nebula caused by the collision of two waves of gaseous emissions by the "bright" (7th-magnitude) star near its center, WR 136. The star is an approximately 4.5 million year old Wolf-Rayet star of perhaps 40 to 80 solar masses. Wolf-Rayet stars are very massive, extremely hot stars (originally O-type Main Sequence stars) which are near the end of their lives. A few hundred thousand years ago the star swelled up to become a red super-giant and ejected a few tenths of a solar mass of gas at about 20 thousand miles per hour. About 200 thousand years later, it heated up to several hundred thousand degrees, and began ejecting about a solar mass of super-heated gas per ten thousand years, at nearly 1% the speed of light (3 to 4 million miles per hour). As the faster moving, the hotter gas reached the slower-moving, cooler gas previously released, it created a supersonic shock wave, causing the nebula to emit visible (primarily red H‘) light, as well as ultraviolet and X-radiation. The complex filamentary structure of the nebula is real, but its spherical structure is tissue-thin in comparison to its size. Only the surface of the structure is glowing; the hot gas streaming away from the star is essentially invisible. Within a few thousand years the current nebula will fade away, as its gas disperses into the surrounding space; but within a hundred thousand years, a new and even more spectacular nebula will form when the star supernovas. WR 136 and its nebula are about 4700 light years away. Given that and the approximately 18 by 12 arcmin apparent size of the nebula, NGC 6888 is about 25 light-years across."

This was my first attempt at merging H alpha with color data back in 2007. I didn't do it right as I was working in ignorance. Nor did I take the data correctly for such a combine. This is another image I need to retake but over 10 years later that hasn't happened. Due to my errors, I'm reproducing this one at 2" per pixel rather than my normal 1" per pixel as it hides some of my errors.

14" LX200R @ f/10, Ha=3x30', RGB=3x5', STL-11000XM, Paramount ME

Related Designations for NGC6888

NGC6894

NGC 6894 is a planetary nebula in Cygnus. It may be about 5.000 light-years distant. It was discovered by William Herschel on July 17, 1784. It is in the second H400 program. While many planetary nebulae are teal in color due to strong OIII emission this one is more red than teal. Whether this comes from H alpha or NII emission I don't know. They are very close emission lines and need a 3nm filter to separate these. Not having such narrow filters and not finding much in the literature I don't know the answer to this question. I'm going to guess it is both with NII being stronger but that is a pure guess with nothing to back it up.

Much longer exposures than mine show that it may be interacting with the interstellar medium. Gasses it emitted before the planetary nebula formed appear to have aligned with the magnetic field of the galaxy. If so this may help to understand the interstellar medium at least in this part of the galaxy.

This is another very early image that needs reprocessing if I ever find the time.

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

Related Designations for NGC6894

NGC6905

NGC 6905, a planetary nebula in Delphinus, is also known as the "Blue Flash". Distances to planetary nebulae are hard to determine unless close enough for trigonometric observation. I found estimates of this one ranging from 3,200 to 8,500 light-years with the most modern estimate (2004) coming in at about 5,300 light-years. Put on the hip waders and read about it at http://adsabs.harvard.edu/abs/2004MNRAS.353..589P .

The nebula was discovered by William Herschel in 1784 with his 18.7" reflector. The central star is a pulsating white dwarf which has a hydrogen deficient atmosphere. It is in the original H400 observing program. My notebook from that has an entry from May 20, 1985 with my 10" f/5 at 180x on a good night. It reads; "Round planetary nebula tucked neatly between a bright and dim field star. No detail is seen though the UHC brightens the view and makes it a bit larger." Apparently, I never noticed the "dim" star was inside the nebula's fainter regions. I suspect I was only seeing the bright center since I called it round rather than pointed on both ends.

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

Related Designations for NGC6905

NGC6910

NGC 6910 is an open star cluster in Cygnus. Cygnus is either a Swan or the Northern Cross depending on how you look at it. Where the cross arms meet or where the wings and body meet on the swan is the star Gamma Cygni also known as Sadr. Around this star is a huge HII region usually just called the Gamma Cygni complex. NGC 6910 is in this part of the constellation. When a club member (Earl Moser) first pointed it out to me in the mid 60's he called the Stickman Cluster. Visually it does look like a stick man though his arms are very short, one carries a bright light. He seems to have a fog light on one foot to help see through all the hydrogen I suppose. Rotate the photo a bit over 90 degrees clockwise to see him standing up. Visually you don't notice the hydrogen at all. Most photos don't show it either as it is very faint. But by using my Hydrogen Alpha filter that shows only hydrogen light it shows up nicely. One source puts it about 3700 light-years distant with an age of about 13 million years. It is reddened by nearly a magnitude yet its stars still look blue. A sign it is a rather young cluster as the age of 13 million years indicates. It was discovered by William Herschel on October 17, 1786. It isn't in either H400 program.

Visually I saw no hint of the hydrogen alpha emission seen in my image. It is rather faint but the main reason it isn't seen visually is that our eyes are quite insensitive to the very deep red color of H alpha light. While my camera has a problem with deep red as well it is nowhere near as bad as our eye's at this frequency and by isolating this frequency, blocking all others, I can take 60 minutes of data without it being lost in the colors it sees better. Our eyes are limited to what they see in about 1/10th of a second. So even using such a filter won't help visually. In fact, we see other wavelengths such as OIII and H beta far better and there are filters for these that can help see faint emission objects. Our eyes are very sensitive to teal and blue compared to deep red so we can see these other colors even if they are much fainter. The camera isn't fooled like the eye so it sees the dominant H alpha with the other colors lightening it up so it's no longer deep red but still quite red.

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

Related Designations for NGC6910

NGC6911

NGC 6911 is a very strange spiral galaxy in eastern Draco about 105 light-years distant by redshift and other methods. It has a drawn out eastern arm and nothing much in the way of an arm on the other side other than the ring the one arm comes off of. Instead there's a disorganized puff of stars where the other arm would be. This is a very lonely galaxy with no others in the field. NED came up empty looking for a related galaxy even far outside my field. So how did it get so screwed up. Is it the product of a merger? I found virtually nothing on this galaxy in the literature. NED has no redshift data on anything else in the image and only a half dozen or so other galaxies are even listed. Those lack even a magnitude reading.

Located far to the north it isn't surprising to find the field full if galactic cirrus, aka IFN. This is dust well above the plane of the galaxy reflecting and sometimes emitting light due to the illumination of the stars of our galaxy below rather than by an individual star as is the case with most reflection or emission nebulae. Unfortunately August turned out to start off as poorly as July with horrid transparency. While the image uses 7 luminance frames I took 16 over three nights to get the 7 I used. They likely have fewer photons than 2 normal frames would. The color data was taken the second and third night with 4 frames each color each night of which one each night was usable. Though I doubt there's even 10 minutes worth of signal in all 8 of each color and only slightly less in the 2 of each I used. So this one is highly suspect as to color. There wasn't anywhere near enough color to pick up the IFN so it is not colored at all. The galaxy is surprisingly red. I think it likely due to dust reddening as it is near the edge of the Milky Way. The "bright" star in the upper right corner is a G3V star so nearly white and that is how it came out indicating the color is likely correct. The blue tinge is normal due to chromatic issues with the corrector lens of the scope which is not color corrected and thus can show this blue tinge on very bright stars.

Again this is an object I can't find posted anyplace on the net in color. At least not under the NGC 6911 name. Nor did I note in my notes why it was on my list other than the notation "IFN?" beside it so somehow I suspected it was there. It is hinted at in the POSS plates so that might be why the note.

NGC 6911 was discovered by Lewis Swift on june 9, 1885.

14" LX200R @ f/10, L=7x10' (equal to about 2x10' on a good night) RGB=2x10' (more like 1x2' on a good night), STL-11000XM, Paramount ME

Related Designations for NGC6911

NGC6914

This object in Cygnus has an identity crisis. Is it the red emission nebula, the top blue reflection nebula or what? Simbad says it is an emission nebula but points different places depending on how you enter Simbad. NED points to the top blue reflection nebula, Seligman points to a bit different area and quotes Dreyer saying "very faint, very large, irregularly round, diffuse, 2 stars attached on west". That might point to the entire region or just what? I can't tell what is meant by 2 stars attached on the west. APOD takes the easy way out and calls it a "complex of Nebulae" and shows a very deep picture of the blue emission nebula rather centered on the lower of the two reflection nebulae near the center of my image but includes the southern one I didn't fully include. There are many images of this region, again with little agreement as to what is NGC 6914. In any case, most agree the reflection nebula I cut off at the bottom is vdB 131 and the middle one is vdB132. I'm going with the upper being NGC 6914. Otherwise, I'd have thought it too would have a vdB designation. Vdb 133 is a very different reflection nebula in Cygnus which I've also imaged. The bright emission nebula along the left side is LBN 273 (south part) and LBN 281 (northern part). The dark nebula above and right of NGC 6914 is LDN 899. At least that's my take on this field.

This was one of my first attempts on a field like this taken back in 2007 when I had poor processing skills and tools. I had started to learn what it takes to image such a field. I got lucky with the processing. I tried several more times in 2007 to improve this image and each time it got worse. I put it down ignorant beginner's luck. The original data is on a hard drive in the basement buried who knows where with a backup in the safe deposit box 22 miles from here. I lost my entire film collection when a large oak limb on a tree came through the roof in the attic where all prints, negatives and slides were stored. Except for a few elsewhere nearly 50 years of film work was wiped out. Now I'm paranoid and have backups of original data two places miles apart and the TIF and JPG images several more places.

Due to no H alpha, the emission nebula was weak. I hoped 80 minutes rather than my usual 40 of luminance would compensate but it didn't. Due to the noise being a bit higher than normal due to insufficient data I reproduced this at 1.5" per pixel rather than my usual 1" per pixel. That hides a lot of the noise.

14" LX200R @ f/10, L=8x10', RGB=2x10' no H alpha, STL-11000XM, Paramount ME

Related Designations for NGC6914

NGC6922

NGC 6922 is a very strange face on spiral in Aquila. Not exactly a constellation known for its galaxies. NED classifies it as SA(rs)c pec: with HII emission. The HII seems well below my poor seeing limits. Its redshift puts it some 250 million light-years distant which doesn't help my resolution any. It is about 70,000 light-years across at its widest point. A note at NED asks: "Small companion superimposed?" I assume this refers to the small fuzzy white object to the right (west) of its core. Unfortunately, this field is located deep in the Zone of Avoidance so there are few surveys of galaxies conducted in this area. Whatever that white fuzz ball is it isn't listed in any catalog I found. It appears to be either a huge star cloud in the galaxy or another galaxy. If a galaxy is it beyond or in front of NGC 6922? If the latter it is likely a compact dwarf of some sort. NGC 6922 was discovered by Albert Marth on July 24, 1863 using a 48" reflector. You can see a drawing of this nightmare to use scope at: http://www.klima-luft.de/steinicke/ngcic/persons/lassell.htm . I have to wonder what these astronomers would think of what we amateurs can do today with far more convenient scopes and computer imaging.

The one odd arm of this galaxy is what drew my interest. It seems to fit Arp's class for spiral galaxies with one heavy arm. Though the entire shape of the galaxy is distorted. The arm also has at the southern end a short linear "thumb" sticking out to the east. Really odd. The overall distortion of the disk portion points to the fuzzy white object. Putting all this together it appears quite possible the white fuzzball is the core of something it is digesting after having stripped many of its outer stars away. Though this is only conjecture on my part. No one has studied this galaxy that I find so until then speculation is about all I have to go on.

With a field so deep in the Zone of Avoidance, only two other galaxies in the field have redshift data. The near edge on galaxy at the top center of the image is 2MFGC 15552 or PGC 064812 for those telling me to use the PGC catalog. I prefer the 2MFGC because it helps describe the galaxy as being a flat edge on galaxy but telescope pointing programs often prefer non-descriptive names. In this case, NED makes no attempt to classify it so the name is all we have to go on. It is also about the same distance at 240 million light-years. That makes it a bit less than 50,000 light-years in length. At the bottom left of the image is PGC 064854 at 260 million light-years. It too is unclassified at NED though appears to be an S0 type galaxy about 60,000 light-years in size.

Many other, mostly severely reddened galaxies can be seen in the image but NED has nothing useful on them, most aren't even listed at NED. Though some galaxies aren't reddened significantly, including the three we have data on. This indicates to me the dust that is reddening these distant galaxies lies more than 250 million light-years beyond our galaxy rather than being due to dust in our galaxy.

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

Related Designations for NGC6922