SH2

Related Designations for SH2

SH2 120

Sh2-120 and Sh2-121 are a pair of emission nebula in Cygnus about 5 degrees north of the far more well known North American Nebula, NGC 7000. There is a lot of confusion in the catalogs about these two much to my surprise. Sh2-121 is listed as a galaxy in The Sky, PGC 2349711. SIMBAD misses the position of Sh2-120 by about 4 minutes of arc putting it where nothing is to be seen. Galaxy Map says that both 120 and 121 are at the same distance of 7500 parsecs (24,500 light-years) under their entry for Sh2-120. Under Sh2-121 they cite another source as putting it at 4500 parsecs +/- 1000 Parsecs (14,500 light-years +/- 3000 light-years). Then in a third paragraph says it is at a distance of 6500 parsecs (21,000 light-years). In other words, determining the distance to these is full of uncertainties. The citation that puts it at 6500 light-years adds that it is surrounded by an expanding shell containing about 39 solar masses of gas that is about 650,000 years old. All this driven by an O8.5 star. Which star that is I don't know.

The H alpha data was mixed using lighten mode with the percentages shown. I've found this mix retains the color seen in RGB images, at least with my system.

14" LX200R @ f/10, L=4x10'+Ha=2x30', R=2x10'+80% of the Ha data, G=2x10'+5%Ha, B=2x10+20%Ha, STL-11000XM, Paramount ME

Related Designations for SH2 120

SH2 271

SH2-271 and SH2-272 are two emission nebula, part of a much larger mostly invisible to visibly light molecular cloud in northern Orion just east of his club. The naked eye B9 blue giant star, 73 Orionis, is in the upper left of my image. It created havoc in processing this image as it scattered a blue gradient everywhere. I have severely retarded this star so it appears many times dimmer than it really is at magnitude 5.4.

Many catalogs, including the database in my The Sky 6 program say the larger nebula, SH2-271, a planetary nebula calling it PK 197-02.1. It's in other planetary nebulae catalogs as well according to SIMBAD. The nebulae are excited by the two stars seen in their centers, an 09V and B1V stars. For some reason, SIMBAD locates SH2-271 4.5 minutes of arc east of its location and SH2-272 0.4 minutes west of its location. I don't know why the errors. The Sky makes the same error for SH2-271. SIMBAD also places a star cluster midway between the two nebulae's actual positions. Most of these stars are seen in IR rather than visual light as they are buried deep in the molecular cloud, two small parts of which make up the two visual nebulae.

While sources vary for a distance to these nebulae most say it is in the Perseus arm and give a distance of 15,600 light-years. Some include an error bar of 4,000 light-years. Distances for objects like this can be hard to determine. Assuming the 15,600 light-year distance the two nebulae span a distance of about 19 light-years.

Conditions were lousy when this was taken. So bad I threw out all the luminance data as too blurry to use due to fogging from high clouds and 73 Orionis. Instead, I used the two red images as less blasted by the star plus the H alpha data to make a pseudo luminance image. The H alpha data was added 80% to the red and 20% to the blue when making the RGB image. That left a severe issue with blue and to some extent green due to 73 Orionis and high clouds scattering its light. I had to use a lot of gradient tools to restore the color balance. Still, there's some glare around many stars. I need to redo this one on a night of much better transparency. I tried this one another night under slightly better conditions and moved 73 Orionis out of the field but that caused highly distorted ghostly images all over the image. These were even worse to deal with and the halos around the stars from the thin clouds just as bad. I never had weather conditions sufficient to try again.

This is my 6th and last February image. I see I saved quite a few more March images. I haven't had time to look at them to see if they are all usable. I am hoping this means conditions improved in March. I just can't remember. I do see this was taken before the end of February and the March images start about a week later due to weather issues.

14" LX200R, HA=4x30' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for SH2 271

SH2-054

Sh2-54/Gum 85 is a huge star-forming region in Serpens Cauda. It is part of the Serpens OB2 Association, a large star-forming region. I couldn't find any distance for it but most consider it related to the open star cluster NGC 6604 (a couple degrees out of my frame). That does seem to have a good distance measurement of 5,500 light-years based on Hipparcos and other sources. Though I've found a very wide range on the net these seem to be based on older, less accurate measurements. For more on this area of the sky see:
http://www.ifa.hawaii.edu/publications/preprints/08preprints/Reipurth_08-209.pdf

Sh2-54 is far too large for my system being about 9 square degrees in area. It does have a brighter area that does fit my image scale so that's the part I centered on. Note there are several "elephant trunk" features in the image. They all point back to NGC 6604 confirming its association with this nebula.

You can see the entire nebula at Dean Salman's website:
http://sharplesscatalog.com/Sharpless.aspx?Sharp=54

Normally I display images with north up. I am making an exception here and have oriented it south up. This is because my sick brain sees this nebula looking like a chihuahua making a rather rude gesture with its front legs. Maybe it should be known as the Rude Chihuahua Nebula? Since a chihuahua's leg can't bend in that direction without breaking that may explain why it is mad. I should mention I'm no fan of that breed. My maternal grandmother carried one wherever she went (long before Paris Hilton). I was 4 and told to kiss grandma good night. The dog chomped on my nose so hard I needed quite a few stitches. Next night I was told to do the same. I put up quite a fight but lost. This time the bandages helped, I only needed two stitches replaced. A couple days later my cat killed the blankety-blank dog much to my glee. The dog annoyed it one too many times. The cat was 20 pounds of muscle (Maine Coon), chihuahua 3.5 pounds of trembling "Jello" and sharp teeth. Is it getting back at me from the skies? My wife claims it looks like a pig but she had no encounters with that chihuahua.

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

I'm falling more and more behind. This was taken August 13, 2010. I've got to start turning them out like crazy it seems. I need some 36 hour days.

Related Designations for SH2-054

SH2-065

Sh2-65/LBN 91 is a small emission nebula in Aquila just north of Scutum. The bottom quarter of the image is in Scutum in fact. Another emission nebula [KC97c] G029.0-00.6 lies to the west-southwest (right and a bit lower). Many dark clouds are seen in the image. All of these are identified only by their galactic coordinates from the SDC (Spitzer Dark Cloud) catalog so I won't list those. I found one paper putting its distance at 3.3 kpc (~11,000 light-years). The bright star near it, SAO 142615 at a magnitude of 9.65 is listed as an A2 star. These usually aren't strong enough in UV light to cause emission nebulae to glow so I doubt it is the exciting star. I was unable to find any hint of what star or stars are likely supplying the energy to make the clouds glow.

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

Related Designations for SH2-065

SH2-071

Sh2-71/LBN103 is a planetary nebula in Aquila a bit over 3000 light-years distant though the distance is a bit uncertain. Some sources consider the bright star at its center as the center star that created the nebula. It is an eclipsing double star which may explain the nebula's squashed shape. Others however say the central star is the very faint star seen barely in my image to the upper right of the bright star about half way to the double star above it. The nebula was discovered by Rudolph Minkowski in 1946.

14" LX200R @ f/10, L=6x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for SH2-071

SH2-080

I'll get to the new planetary in a bit first the main object.

This is a retake of SH2-80 aka Merrill's star. It is a Wolf Rayet star and bubble rather than a planetary nebula as it is often cataloged. Much of the red likely comes from nitrogen rather than hydrogen as it is a WN 7 or WN 8 object. The N signifies strong nitrogen emission. Those with 3 micron Ha and NII filters can test this.

This time I took it at my full resolution of 0.5" per pixel though the night wasn't quite up to that. Still the result is much superior to the first image. The nebula contains virtually no OIII emission. When I took it in 2010 I was using my old Astrodon 1 filters. The green came up empty of any hint of green emission though most other images of the nebula show green. This puzzled me and others. Now that I have generation 2 Astrodon filters I wanted to see if that changed anything. It did slightly. Now I see a very very faint hint of green emission but it is super weak. The blue of H beta came through in both but is weak compared to the red. Likely because the red is mostly nitrogen rather than hydrogen emission as it is a nitrogen class Wolf-Rayet star. Still why did most images of this nebula show green when you looked at the color channels. I found out that it was the way the saturation of the image was done. If it was done after combining with the initial color data then pushed to normal levels it showed green that wasn't really there. If the saturation was done totally in the RGB combine and not changed once combined the green vanished -- too much, it turned black rather than staying at background levels. This time I did some push in RGB and some after the combine. Thus there is some green if you look at the posted image but that wasn't there in the original color data. It's an artifact of how the color was combined. I'm going to have to somehow download a copy of Pix Insight (takes hours on my slow internet) and see if it handles this more correctly than I and apparently others handle it in Photoshop. It will be an interesting test.

Now for the other reason for retaking this one. After I posted my earlier image a friend who images from central Berlin, Stefan Lilge, took the same field in narrow band and discovered a small uncatalogued planetary image. He checked my first image and it was there though I'd not noticed it. Not nearly as nicely seen as it was in his image but it did confirm he found something real. When he told me about it I contacted Sakib Rasool who got a pro to image it with the 2.1 meter KPNO telescope. It's discovery was released at a conference last week (2013) so I'm now free to cover it. The object is at 19h 12m 10.3s +16d 46' 35.6". That is in the lower left part of my image above and left of a bright (not the brightest) pair of blue stars. There's a field star that blocked much of the planetary in my LRGB image. Stefan's narrowband image dims the star making the nebula more visible. I tried to tone it down in this image but wasn't all that successful. Stefan's discovery image can be seen at http://ccd-astronomy.de/temp8/Sh2-80/Sh2-80colourcropgut.jpg . Orientation is about the same as mine so it too is to the lower left. Only his field is smaller so it is by the only bright pair of blue stars. The offending star on the right edge of the ring is quite faint in narrow band images. Somehow the Kitt Peak image doesn't even show it and severely dims the other stars in the field, completely hiding many in my image making a comparison hard. The planetary is now known as Li1. Li for Lilge of course. That's his only planetary so I've now completed my first catalog! Small as it is. When I took the second image I'd hoped to pick up the central star but failed. Nor is it seen in the Kitt Peak image though it has greatly suppressed stars so that isn't surprising I suppose. Odd they left in their hot pixels.

Ironically I am always harping on "Know what's in your image". I failed in this case, fortunately Stefan didn't and it is Li1 rather than Jo1. I've included a link to the poster from the conference showing all 37 candidates (greatly reduced to meet size limits) and a full size crop of Li1 from the poster. Note his discovery was made through the severe light pollution of his central Berlin balcony! That shows his great skills as a astrophotographer!

14" LX200R @ f/10, L=8x20' RGB=2x10'x2, STL-11000XM, Paramount ME

Related Designations for SH2-080

SH2-082

Sh2-82/LDN129 is often called the Little Cocoon which it does resemble with the inner emission region and halo of reflection blue though it is much fainter and lower in the sky being in Sagitta. Galaxymap.org puts it at about 3600 light years. It is also known as the Little Triffid though I can't see the resemblance other than both emission and reflection elements are involved with both. The bright star in the center of the emission (red) region is HD 231616 which Galaxymap credits as being the illuminating star. There are several dark nebulae in the image identified at Simbad. But some I really wanted to know about aren't listed. Those that are I've noted on the annotated image though I left off a few that were so indistinct I couldn't see anything at those locations. Yet some very dark ones have no listing. It's very discouraging. SDC stands for the Spitzer Dark Catalog. Since the Spitzer space telescope operates deep in the infrared part of the spectrum it might be these stand out well at those wavelengths. I found no LDN or other visual dark catalog entries for this field.

This one needs a much wider field of view than I can give it. For that See Tom Davis' superb image at: http://tvdavisastropics.com/astroimages-1_000086.htm He used nearly 14 hours of data, over 10 times what I used so shows fainter detail.

Due to two massively bright satellites, one in red and one in green frames that I didn't know were there until I went to process this I am limited in color data for those channels. All attempts to process them out with only two frames failed miserably. Even my old darken combine trick didn't work, leaving some nasty color traces. I really need to put a lot more time into this one this summer.

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

Related Designations for SH2-082

SH2-083

SH2-83A is a small emission nebula with an infrared star cluster hiding within it from some reports. It is in Vulpecula just north of the far more famous Coathanger asterism. In fact, some images of the Coathanger pick up this nebula as well. The Coathanger dwarfs this tiny nebula. I can't find much on it, not even a distance estimate.

I wondered if it was SH2-83A where was SH2-83. According to Simbad, that object is 161 arcseconds southwest of SH2-83A. That puts it a bit over half way from SH2-83A to the right edge of my 0.8" per pixel cropped image on an angle of about 240 degrees from SH2-83A (4 O'clock -- remember west is to the right not east). There's a medium bright (for the frame) orange star just to the upper right of its position. Nothing is seen there in any image of the area I located. If anything exists there it is exceedingly faint. Many amateurs label SH2-83A as SH2-83 though according to SIMBAD that isn't correct. I don't know if the A version is just a correction of the position from an erroneous one or if there really are two objects here. I find working with many of these small nebulae can be very confusing at times.

Since this object is located in the Milky Way the starfield is very rich but held nothing of interest. The stars just blew up the JPG size without adding much. So I cropped the image down to about two thirds size by area but leaving the image scale at my usual 1" per pixel since this one is so small. The cropped image is at 0.8" per pixel.

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

Related Designations for SH2-083

SH2-087

SH2-87 is a faint emission nebula 3.6 degrees northwest of M27 in Vulpecula. Distance estimates range 2100 parsecs +/- 200 parsecs. That's 6,800 light-years +/- 650 light-years for the parsec challenged out there. Another source put it at 7,500 light-years. It seems to consist of a large very faint cloud with two bright condensations and a moderately bright region east of the eastern bright region. Unfortunately, it was very low transparency the night I took this so I missed most of the faint region that extends east and north of the two bright regions. Also due to clouds of the 4 color frames per channel, I took only one of each color was usable and the blue channel was especially poor so my color is very suspect, especially in the fainter regions. I need to put this one back on the redo list for next summer.

The two condensations carry the very odd names of [CZY2003] S87E and [CZY2003] S87W, left to right or I should say east to west as the last letters indicate. These house Infrared star clusters. The eastern one appears to be the result of a collision of two star clouds.

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

Related Designations for SH2-087