SH2-261

Sh2-261 also known as Lower's Nebula is an HII region probably illuminated by the O7.5 runaway star HD 41997. That is the bright blue star toward the top center of my image just above the brightest part of the nebula. I found distance estimates to the nebula ranging from 1000 to 3000 parsecs distant. If the closer is right it is part of the Orion arm of our galaxy. If the more distant ones are correct it is part of the Gemini OB1 complex. The Sky lists the Hipparcos data as showing the star to be 909 parsecs distant making it part of the Orion arm and not the Gemini OB1 complex quite a few papers seem to show it. Sounds like more work needs to be done on this one.

The nebula gets the name Lower's Nebula as it was photographed by an amateur father and son team (Harold and son Charles Lower) in 1939 with their 8" f/1 Schmidt camera they'd constructed a few years earlier.

The nebula is a huge squashed ring several times larger than my field of view. I just selected the brighter part of the bottom of the ring. It is best seen in H alpha light but it contains some reflection components around the illuminating star that I wanted to pick up so I used LRGB imaging without any H alpha added. Unfortunately, conditions were rather poor for this image with high clouds creating a glow around the brighter stars that I only sort of eliminated. It also reduced my ability to pick up the fainter parts of the nebula without more noise than I'd normally tolerate. Probably another for the reshoot list that probably won't happen.

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

Related Designations for SH2-261

SH2-269

Sh2-269 also known as LBN 876 is a small star-forming region in northern Orion just east of the top of his club. It is thought to be ionized by the B0.5V star in its western (right) half. Just which star that is I've not determined. A second similar star is so buried in the nebula it is seen only in IR and likely also helps to ionize parts of the cloud. Its distance is thought to be about 12,400 light-years. A recent paper says 13,200 but has error bars that put it somewhere from 11,600 to 15,300 light-years. This was based on parallax measurements radio masers in the nebula. The problem is they have their own motion about the star cluster that is forming in the cluster which makes determining their radio parallax difficult hence the large error bars.

There's a nasty B1V star at 1370 light-years just east of the nebula. It created a huge blue circle running right through the nebula about where the dark lane runs. My usual technique is to take a similar blue star, remove the stars then subtract that star from the one in the image. That sort of worked but if I totally removed the artifact I damaged the nebula as well. I think I finally found a compromise that got rid of most of it and left the nebula alone. Bright blue stars and Schmidt Cassegrain corrector plates don't play well together.

Most images of Sharpless objects are done narrowband. I took this in LRGB without any narrowband. I suppose NB would have eliminated the issue with the B1V star but otherwise seems to add little to this object.

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

Related Designations for SH2-269

SH2-274

SH2-274 also known as the Medusa Nebula and Abell 21. Young planetary nebulae are small and usually blue but old ones are huge and red. The size is related to age since these are shells of gas puffed off when a red giant star runs out of fuel and the core collapses. The intense heat generated by the collapsing core pushes the outer envelope of the star away faster than its escape velocity so the gasses just keep going making an ever larger shell about the star. Eventually, these gasses run into the interstellar medium. When the star was still "alive" it blew a hole in the interstellar gases making a nice hole for itself. But when it died at became a white dwarf (actually they are so hot they are blue so the name is rather wrong) it could no longer keep the hydrogen and other gasses between the stars away and it slowly starts to fill in the "hole". At the same time the shell it blew off expands until it hits the more slowly moving incoming gases. The collision usually glows red. The color of HII emission caused by this collision. In this case, the bubble has hit the interstellar medium first on the left side. The right side as only hit a small amount of material so the bubble looks unsymmetrical. Since the blue "white" dwarf is pretty much in the center we know either the gasses blown off were less toward the right or they haven't yet made contact to any extent. The latter appears to be the case. As the planetary ages, the white dwarf cools and no longer has the energy to cause the gasses to glow on its own. In this case, some blue can still be seen mixed with the red indicating it is just barely able to excite the bubble to glow. The cooling of the star plus the increasing size of the bubble has reduced the radiation hitting the bubble to the point most of the glow is coming from the collision with interstellar gases. The "white" dwarf still shows strongly blue in color indicated it is still quite hot and it is mostly distance that has limited its ability to light up the nebula rather than its temperature. Seeing was lousy the night I took this image, much as it usually is this time of the year. Another for the reshoot list that never happens.

14" LX200r @ f/10, L=4X10' RGB=2X10', STL-11000XM, Paramount ME

Related Designations for SH2-274

SH2-282

Sh2-282 is an emission nebula excited by HD 47432, an O9 star which is the bright star that gave me fits in the upper left of the image. It seems to be surrounded by a faint bubble or maybe just an arc of HII emission. I thought it part of the horrid reflection it gave me but it is real. Galaxy map puts it about 5000 light years distant one place and another says it is about 4000 light years away. Take your pick. I can't fit it all into my frame so picked the more interesting, to me at least, part to include. Galaxy map says it contains 8 cometary globules. What I see are lots of dense shock fronts all pointing right to the exciting star.

This is an HaLRGB image. HA was added to the luminosity data using the lighten mode. It was added at 80% to the red image, 10% to the green and 20% blue also using lighten mode. Stars were removed from the H alpha image before the blend so are pure LRGB. The image is noisy. I needed considerable more H alpha time. If I find time to get more I'll rework it. This data is from last January.

Due to the noise and lack of fine detail, I've reduced this one to 1.5" per pixel. It fits monitors better at this size as well.

14" LX200R @ f/10, Ha=3x30' L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for SH2-282

SH2-80

Sh2-80 goes by so many designations I don't know which to use (SIMBAD lists 30!). But since I've been imaging some small Sharpless objects I'll use that. It is an 11th magnitude Wolf Rayet star, WR 124 (Merrill's Star, for Paul W. Merrill who specialized in spectroscopy of strange stars -- he also has a lunar crater named for him) surrounded by a nitrogen rich bubble. Some catalogs, well many, consider it a planetary nebula but it is really a Wolf Rayet bubble much like NGC 6888, the Crescent Nebula, in Cygnus. Thor's Helmet is another such bubble. The star is classed as spectral type WN 7 or 8 depending on who you listen to. The N means it is nitrogen rich, the 7 and or 8 means the NIII line is stronger than the NIV line. NIV is weaker in WN8 than WN7 in case you were wondering.

I can't find much on this guy, no distance estimate so no size estimate, no age info etc. Just a ton of names for the star and nebula, many being incorrect PN designations such as M 1-67 and G050.1+03.3.

Last fall Bill W posted a nice shot of it. At the time I thought I'd not imaged it. It has been on my list for years as Merrill's Star. Turns out this was taken the end of August but under the Sharpless name. My brain failed to connect the two. After seeing how much time Bill put into his shot I was doubtful I'd get it, but it came through very nicely with only 40 minutes of luminosity data.

Seeing was poor this night. No H alpha was used. I had several nasty satellites go through the color data and one in the luminosity data. With only 4 frames noise rejection didn't work well, my algorithm needs at least 6 to be of lower noise than a simple add or average combine. So it was left in rather than clone out a bunch of stars along with the satellite. I did remove the color ones as they didn't harm many stars. Just too many stars to clone it out of the L image. This bubble must not contain any OIII emission. That falls partly in my green and blue filters which overlap a tad at the OIII line. Yet the green filter showed no hint of the nebula while the blue showed the right intensity for H beta emission without any OIII contribution. Maybe someone with an OIII filter can verify this. Taken August 27, 2009 UTC.

Cropped image enlarged to 0.5" per pixel for those with small dot pitch monitors.

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

Related Designations for SH2-80

SHK166

Shk 166 (Shakhbazian 166) is a chain of galaxies within the much larger galaxy cluster Abell 2247. It is located in Ursa Minor not far from Epsilon. It lies about 520 million light-years away. Since all of the galaxies in my image with redshift data are members of the group and cluster I didn't include distance information. A single flat plane estimate of its distance also comes up with the same distance, a surprisingly good agreement!

Abell 2247 is listed as having 30 to 49 members in a 3.25 degree circle. That's many times the size of my image. I've labeled the center position in the Annotated image. Oddly the galaxy closest to the point has no redshift or other distance data at NED. This far north (81.6 degrees) there has been little study made on galaxies. In fact, the only listing for the blue galaxy above the Abell 2247 label is as an Ultraviolet source not even recognized as a galaxy at NED. I find a lot of interesting objects that lie out of the area of major studies and thus lacking information I'd like to have. A case of too many galaxies for the few grad students available to study them. Especially when there are bigger questions to be worked on than just basic data collection.

Arp had a classification for galaxy chains like this one. But this wasn't one he included. Whether the chain, in this case, is real or just chance alignment due to our position in space is subject to debate. Like most clusters, it appears the galaxies have throttled down star formation so only red an dead galaxies are seen in most clusters, even those, like this, without a major central galaxy to serve as a gravitational center. Even the one spiral is made up of mostly old stars.

Romelia Shakhbazian (1926-2012) was an Armenian astronomer who cataloged compact galaxy groups, mostly not making Hickson's more limited list. Some like this one are dense portions of much larger galaxy clusters. I found only a few interested me enough to make my to-do file. I've already posted Shk 1 and Shk 16. The latter as part of my effort to catch as many of Arp's entries as possible. It is Arp 330. A few more are still on the list but not yet taken. Maybe another year. Romelia died in 2012 at age 85 mostly unheard of by amateurs.

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

Related Designations for SHK166

SHK30

SHK 30 also known as HCG 69 is a group of galaxies in southwestern Pisces. In the HGC it consists of 5 galaxies, A through E. In the SHK list those are 1-5 respectively. But it goes on with 6 through 11 and A through D for 15 galaxies. While all of the HCG galaxies and thus the SHK 1-6 galaxies are about 270 million light-years distant that isn't true of some of the other SHK galaxies. C, for instance, is listed at over 3 billion light-years. Others have no redshift data at NED. The most interesting of these is B which is an obviously disrupted galaxy of some sort. In my image, it appears to be two galaxies but high-resolution images show it to be one disrupted galaxy. The star at the southern end makes it appear comet-like further confusing things. I wish I could find something on it but I can't. Its blue color differs greatly from the other members. That may just be due to star formation caused by the disruption.

Another odd galaxy is NSA 152639. Its distance indicates it could be a group member. In my image, it too is somewhat comet-like with a head at the south end. At first, I suspected it and B might have tangled in the past. But high-resolution images of it show it a double galaxy. The NED position points between the two, a bit closer to the eastern member. It is larger and has an off-center core causing the "comet" head. So it may be an interacting pair of dwarf galaxies.

The two PGC galaxies to the southeast have redshifts that indicate they too could be members of the group, just too far removed to make either compact group catalog.

My system imaged this one on a very poor night. So poor it retook one green and both blue frames. Once I saw the data I realized all data from the first night needed to be retaken but by then it was too far west. Why my system accepted such poor data I don't know. When I ran it through the filter all was rejected but it only three color frames were rejected that night, yet it's the same filter. This isn't the first time that's happened but I thought I knew the problem and corrected it. Apparently not. The red data was one third the strength of the retaken blue and green and due to clouds, the stars were much smaller. This made reconstructing the color difficult. Even eXcalibrator couldn't help much. Color is mostly adjusted to what I am guessing it should be. The luminance data too, is very weak and very noisy, falling a good 2 magnitudes short of normal. A lot of fainter features of these galaxies is lost.

All 5 HGC members are in the IC catalog. They were discovered by Edward Barnard sometime in 1889. His records are too incomplete to pin it down further.

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

Related Designations for SHK30

SSTC2DJ033044.0+303247

Deep in the Perseus Dark Cloud is the cometary reflection nebula GN 03.27.6. It is lit by emission line star LkHa 326. This is also a young stellar object candidate. The cloud is thought to be about 300 parsecs distant or about 1000 light-years. With the field deep in the cloud, it has a dark and dreary appearance, about like the weather I've had trying to image it. Several other young stellar object candidates (Y*Oc) are in the field as are T Tauri stars (TT*). Both would be considered protostars still heated mostly by gravitational collapse rather than their yet to ignite nuclear furnace.

I wasn't able to find much on the field. Seemed many of the papers were behind paywalls. What I did learn about the field is shown in the annotated image.

I don't recall what drew me to put this field on the to-do list. Probably someones posted wide field of this area in which the cloud showed up as a small low-resolution object that peaked my interest. Usually, I note whose image that was but I failed to do so for this one.

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

Related Designations for SSTC2DJ033044.0+303247

STOCK12

Stock 12 is an open cluster in Cassiopeia. Webda puts it at 1300 light-years and shows an age of just under 300 million years. It has virtually no reddening other than my smoke may have added. The cluster is classed as IV 2 p. The smoke was nearly gone for this one so the colors were easy to adjust after far too many that were so damaged I have no idea how accurate the color is. This one stands out strongly after weeks of images so low in contrast thanks to the thick smoke. There's little on this cluster. Only one galaxy has redshift data. It is to the upper left of the center of the image and the brightest galaxy in the image it is 2MASX J23362696+5242419 at 480 million light-years. I didn't prepere an annotated image for this one galaxy. Many others are visible thanks to little smoke for a change but they have no data at NED other than position. Most don't even have a magnitude.

I am following in the footsteps of Dan Crowson who took it over a year ago. Except for his much lower resolution image I've not seen it posted here before. I picked a previously imaged cluster because I was after something simple to process after weeks of super nasty smoke. For that it worked nicely.

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

Rick



http://www.mantrapskies.com/image-archive/OTHER/STOCK12/STOCK12L4X10RGB2X10-67.JPG
http://www.mantrapskies.com/image-archive/OTHER/STOCK12/STOCK12L4X10RGB2X10.JPG
http://www.mantrapskies.com/image-archive/OTHER/STOCK12/STOCK12L4X10RGB2X10CROP-67.JPG

Related Designations for STOCK12

Thommes Nebula

On November 21, 2009 amateur astronomer Jim Thommes took an image of the rarely imaged LBN 1022. He noticed a small nebula south of LBN 1022 where none was charted nor does any show in the POSS 1 plates though a hint of something is seen in the POSS 2 plates taken mid-sixties. The later IR plate shows a bright round patch south of the nebula's position but nothing at its location other than a faint 20th magnitude star. Jim reported this find to the pros and now, over 2 years later, a preprint of the resulting paper is now available on the net.
http://www.ifa.hawaii.edu/users/reipurth/PREPRINTS/ms_V900Mon.pdf

This is very similar to McNeil's nebula though smaller and in a rarely imaged part of the sky in Monoceros. When Jay McNeil announced his find it quickly became known as McNeil's Nebula. Amateurs rushed to get an image of it. Oddly that isn't happening with this suddenly appearing nebula. Likely because it doesn't lie in a spectacular part of the sky. In an effort to remedy this I'm calling it Thommes' Nebula in hopes it will gain traction in the amateur community.

The paper indicates a preliminary distance estimate of 1100 parsecs which is about 3600 light-years.

While the paper refers to the small nebula north of Thommes Nebula as RNO78 this is not quite correct. That refers to a patch of interstellar matter that is dark in visible light unless lit by embedded stars. Its position is a bit west of the visible light nebula which is the reflection nebula GN 06.54.8.02. Technically it is likely part of RNO78 but has its own designation. LBN1022 is the large, mostly H alpha emitting nebula further north. It has a reflection nebula component as well that is blue rather than H alpha red.

I took this image under very poor conditions in 2009 right after Jim announced his discovery mainly for verification purposes and to see it at a larger image scale. Then I forgot about it until cleaning the hard drive. Forgetting entirely about its history I tried to identify his nebula after seeing it in a 2012 image I took of LBN 1022. Since it isn't yet in the formally published literature I came up empty and was getting all excited. Then I found the preprint paper and it all came back to me. Oh well.

Jim's discovery image is at:
http://jthommes.com/Astro/LBN1022.htm

The best image of this one was taken recently with a 32" scope on Mt. Lemmon by Adam Block. It doesn't appear to have changed all that significantly since Jim found it. I hope to try again if the sky will ever cooperate. Hard to compare Adam's super image to my blurry one and tell if it has brightened or not.
http://www.caelumobservatory.com/gallery/lbn1022.shtml

Since the area is so poorly imaged no one has pinned down when it actually appeared that I can determine. Hints can be seen in the POSS 2 red plate taken sometime in the mid 60's (I don't know the exact date) but that could be noise. After that until Jim's image nothing is known. If anyone knows of any images of this field between these dates it could be very helpful in learning when the eruption began. The preprint paper seems surprisingly confident about their conclusions on this object. Most first papers take a far more cautious approach. I don't think I've ever seen such a paper use terms like "bona fide" before. "possible" would be the normal term to use.

For those I hope will image this one the coordinates are 6h 57m 22s -08d 23' 22". I'll get a current image if the sky every cooperates.

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

Related Designations for Thommes Nebula