PGC87293

LEDA 087293 (also known as PGC 087293) is a strange ring galaxy in the southwest corner of Bootes. NED classifies it as, well, nothing, which I found surprising. Another catalog, the Low Surface Brightness Catalog lists it as a Ring galaxy but then things get confusing. Their position has an error bar radius of 37.5" but the position is about 45" from the galaxy's core. With nothing else looking like a ring it appears they are talking about the ring I imaged. Both LEDA and the LSBC have redshifts for it but again they can't agree. LEDA says 1.72 billion light-years while LSBC says only 520 million light-years, less than one third the distance. But then there seems to be a second galaxy within the ring. A fainter one is seen to the left of the central one. LEDA's position matches the brighter central one. Could it be that they really meant the fainter and possibly more distant one? The GALEX satellite records a UV source halfway between and slightly below the two "cores" but its error bar radius is 3" and thus can include both objects! It is closer to the faint galaxy. So which it means can't be determined. If the LEDA distance is used the ring is 250,000 light-years across. If the LSBC distance is used then it is only 75,000 light-years across. Neither NED nor SIMBAD shows an object at the position of the second core unless it is the GALEX object. Here I thought I was imaging a neat galaxy. I didn't realize I was actually imaging a can of worms.

The LEDA distance of 1.72 billion light-years is echoed by many other galaxies in the field as shown by the annotated image. NED shows several small galaxy groups with this distance and one large galaxy cluster GMBCG J208.39970+09.70305 centered to the easy at 1.69 billion light-years and having 23 members. With no size given, I can't tell if it encompasses all galaxies at about the 1.7 billion light-year distance but I assume it likely does.

The field contains two possible quasars besides some identified ones. One is lists as a candidate quasar by NED so is labeled CQ while the other is listed as an Ultraviolet Excess Source so is listed as UvES in the annotated image.

Transparency was poor for this image. I tried over several nights but much of the data was unusable. One luminance frame was taken a night when an asteroid, (460453) 2014 SV218 was in the frame. It was listed as 19.4 magnitude but appears a magnitude fainter showing how poor the night was. With only a single 10 minute trail, some of which was lost to clouds it hardly looks like an asteroid in the image. Look west of LEDA 087293 to find it in the annotated image. I used the three best color frames for color data due to very low transparency. Turned out one RED one hurt more than it helped so only 2 red ones were used though one happened to be when skies were rather good so that alone likely would have been sufficient though I used two.

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

Related Designations for PGC87293

PHILPLAIT

On February 28, 2009 I attempted to catch the asteroid Philplait. It was a faint one and my asteroid skills were nill at the time. Due to using 10 minute exposures, the asteroid was a short streak in each frame. So the movie shows a short 4.5" streak moving rather than a dot. Today I could either track the asteroid and let the stars make short streaks so I could then take the stars letting the asteroid streak. The two could then be combined so a dot moved through the stars. I didn't know how to do that back then.

The naming citation reads:
(165347) Philplait = 2000 WG11
Phil Plait (b. 1964) is an astronomer, educator and author, currently
based in Colorado. Since 1998 Plait has educated the public and debunked
astronomy myths and misconceptions through his popular website, books and
media appearances.

I've been doing asteroids of folks like Phil that debunk bad science of all types, not just astronomy.

This one used 8 10 minute frames at a resolution of 1.5" per pixel so each streak is about 3 pixels long.

There are two other asteroids in the image 167642 2004 DK50 to the right and 2004 FJ28 to the left. The night was poor with clouds constantly present. You see them, especially in the two fainter trails. That's why the brighter stars have halos. I now can remove those but couldn't back in 2009.

14" LX200R @ f/10, L=8x20x3, STL-11000XM, Paramount ME

Related Designations for PHILPLAIT

PK030+06.1

PK 030+06.1 is a planetary nebula better known as Sh2-68 in Serpens Cauda. It is "A Planetary Nebula Leaving it's Mark on the Interstellar Medium" as one paper on it is entitled. Hey, a paper without some stodgy title for a change. http://adsabs.harvard.edu/full/2003IAUS..209..525K. According to the paper and other sources, its distance is still undetermined.

It is a very old planetary, at least 45,000 years old according to the above paper. Its expansion and movement through space has been halted by the InterStellar Medium (ISM). Now the nebula is moving with the ISM and no longer following the motion of the central star. This is why it is found off center to the southwest. The nebula has been moving through the ISM for at least 45,000 years and leaving a tail of stripped material behind. Some of this is seen in very deep narrowband images. Being a contrarian I decided to see what I could pick up using LRGB only from my very dark location. I put the nebula low in case I picked up the tail running up and to the left. Turned out my sky that night had severe sky glow which drowns out any attempt at picking up the tail, at least with only 40 minutes exposure time. The off-center, very blue (somewhat cyan), central star stands out against the mostly dust reddened background stars. All those dust reddened stars show the density of the ISM it is passing through. The nebula's prior expansion and now cooling central star means it gets somewhat less ionizing radiation than a young small planetary which results in its faintness. It appears the ISM is putting more drag on the smaller and lighter ionized hydrogen atoms than the OIII as most of the red of the ionized hydrogen is found behind the blue OIII regions. This is far more obvious in narrowband images, however. I do need to revisit this one sometime with narrowband filters.

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

Related Designations for PK030+06.1

PK164+31.1

This nebula goes by several names, Jones-Emberson 1, PK 164+31.1, AG82 95, PN VV 47, The Headphones Nebula and even NGC 2474-5. The latter is a mistake as NGC 2474 and NGC 2475 are a pair of galaxies not far from this planetary nebula in the sky. In case you were wondering PK stands for Perek Kohoutek, two Czech astronomers who compiled this catalog of mostly planetary nebula. It was supposed to be all planetary nebula but some have since turned out to be something other than a planetary nebula. You may have heard of Kohoutek, he found a comet that was predicted to be big and bright beyond anything ever seen and it wasn't. That wasn't Kohoutek's fault, he just found it, others predicted great things that didn't happen. Still, it wasn't a bad comet at all.

While this planetary is often photographed as it is a big challenge being so faint, little is known about it other than a distance estimate of 1600 light-years. To recap, planetary nebula are formed by the gasses puffed off as a dying star evolves from the red giant stage of the death process to the white dwarf stage. Only when the star is really still so hot as to be a blue dwarf does the nebula glow. The dwarf is no longer generating energy by fusion though it may still be contracting and getting some energy from gravitational collapse it is cooling. Within 50 to 100 thousand years the star is either too cool to cause the gasses of the nebula it created to glow or the gases have expanded so far from it they no longer get enough ultraviolet light to glow. Either way, these nebulae are short lived. Big ones like this one are faint for several reasons. The gases have spread themselves so thin there's little gas to glow, the gas is so far from the star it gets little ultraviolet light and the star is now cooling so emits less ultraviolet light. Only dwarfs that start out unusually hot remain hot enough to show planetary nebula of this size. Since it is very hard to measure the distance to a white dwarf the size and distance of planetary nebula are nearly always vague or totally unknown as in this case. Assuming the 1600 light-year distance is correct I get a size for this planetary of 3 light-years for its longest dimension. Its size would indicate it is a very old (for planetary nebula) but that's about all we can learn. Seeing was awful when I took these images so the resolution is poor. For this reason, I downsized it to the equivalent of 3x3 binning though the data was all taken at 2x2 binning -- a mistake considering the seeing. I needed 9 nights to get the data for this object all taken in November and December. Bad seeing makes blobs out of some of the galaxies. Several are seen right through the nebula.

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

Related Designations for PK164+31.1

PK24+5.1

http://www.pbase.com/jshuder/image/136810005/original NB IMAGE
aka MINKOWSKI 4-9
http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?2004MNRAS.353..589P&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf
______________________

On the Edge of Darkness

Minkowski 4-9 aka PK 024+05.1 is a nice planetary nebula in a great field. The dark Nebula to the west is LDN 472 with LDN 469 to the southwest. Strips of dust can be seen even on the eastern side of the field as the color of the stars seems very uneven being redder in thin veins indicating a lot of dust in the area. Distance estimates are all over the place for this one. The newest I could find says about 5,600 light-years. The paper goes into how this was determined showing the difficulties involved with measuring planetary nebulae distances. The PDF is at: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?2004MNRAS.353..589P&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf
Assuming the 5,600 light-year distance the nebula is about 1.3 light-years across its longest dimension and 1.1 across its semi-major axis.

I get asked a lot why I use such a large chip when I image such small objects. This image is a good answer to that question. To me the setting is as important as the object. This one could use an even larger FOV for this small object.

For a great high resolution narrow band image of this nebula see Jim Shuder's image at: http://www.pbase.com/jshuder/image/136810005/original

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

Rick

Related Designations for PK24+5.1

PK49+2.1

PN G049.4+02.4/M 4-12/Hen 2-428/PK 049+02.1 among its many designations is a rather distorted planetary nebula in northern Aquila. Its shape is likely due to distortions caused by its interaction with the interstellar medium. I found one paper putting it at 1000 parsecs +/- 100 parsecs. Several papers say the central star is a binary star.

As a bonus, there's a second planetary in the image. Its central star is very bright and hides most of it. This would be a good candidate for narrowband imaging which would dim the central star allowing the nebula to be seen. It is PN G049.3+02.3. See the cropped annotated image at 0.67" per pixel to find it.

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

Related Designations for PK49+2.1

PK62

M2-48/Hen 2-449/PK 062-00 1/PN G062.4-00.2 among other designations is a small planetary nebula in Vulpecula near the far more famous M27. I found two very different distance estimates for it, one says 1100 +/- 300 Parsecs (3600 +/- 1000 light-years) and the other says 7160 parsecs (23,300 light-years). Now that's a discrepancy! Interestingly the first paper listed many planetary distances from several sources including the source for the 7160 estimate but left that entry blank! Apparently, they didn't trust it enough to include. So, for now, its distance is "still to be determined" as best as I can tell.

More of a mystery is why I imaged it in the first place. I normally keep good notes about this but drew a complete blank on this one. I can't even find it in my to-do list yet I took it anyway. I also come up blank for any amateur images of it on the net. I did file it under one of its catalog names so knew what I was taking. The why is totally lost, however. So this is a short entry.

I did find a somewhat readable paper on it by some astronomers who knew why they looked into it.
http://cds.aanda.org/articles/aa/pdf/2002/23/aa2425.pdf

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

Related Designations for PK62

PLN84+11

K 4-55 aka PLN84+11 is a planetary nebula between the North American/Pelican Nebula complex and Deneb. A very commonly imaged field yet no one seems to notice this planetary. I couldn't find a distance for it. It is a very red ring with an outlying spiral nebula like structure. The red color is due to ionized Nitrogen (NII) rather than Hydrogen-alpha. A picture from the HST is available at http://www.spacetelescope.org/images/opo0921a/ . For this false-color image, red comes from NII, green from H alpha and blue from ionized oxygen (OIII). You can read more about this nebula at the HST link.

I tried several times to get H alpha/NII light (my filter picks up both) on three different nights. All suffered from very poor transparency. I did get a bit of data the third try which I added into the red channel of this image but it really made virtually no difference. Also seeing was lousy as well so I didn't get the resolution I wanted. This is another to revisit if I ever get a better night. I picked up no sign of the central star that causes the gasses to glow but then neither did the HST.

14" LX200R @ f/10, Pseudo L=Ha2x30'+L=4x10' R=80%+Ha+R2x10' G=2x10' B=20%Ha=2x10', STL-11000XM, Paramount ME

Related Designations for PLN84+11

PLUTO

Pluto seen against the Milky Way on the western edge of the M24 star cloud. It is shown between the green dashes in one of the JPG images. The dark nebula to the north is LDN 323.

14" LX200R @ f/10, L=2x20' RGB=1x10', STL-11000XM, Paramount ME

Related Designations for PLUTO

PN G100.4+04.6

PN G100.4+04.6/PM 1-333 is listed at NED as a possible planetary nebula though the most recent paper on it from 2009 considers it has proven it to be a true planetary nebula. In the article, they refer to it as PM 1-333. The abstract has this to say about it: "PM 1-333 is an extended planetary nebula with a high-excitation (He II?4686/Hß up to ~ 0.9) patchy circular main body containing two low-excitation knotty arcs. A low Ne([S II]) of ~ 450/cm3 and Te([O III]) of ~ 15000 K are derived for this nebula. Abundance calculations suggest that PM 1-333 is a type I planetary nebula. The lack of a sharp shell morphology, low electron density, and high excitation strongly suggest that PM 1-333 is an evolved planetary nebula. PM 1-333 also shows two low-ionization polar structures whose morphology and emission properties are reminiscent of collimated outflows. We compare PM 1-333 with other evolved planetary nebulae with collimated outflows and find that outflows among evolved planetary nebulae exhibit a large variety of properties, in accordance with these observed in younger planetary nebula."

The nebula was brought to my attention by Aircrftr who found it at the edge of IC 1396 in one of his images http://www.cloudynights.com/topic/474123-what-do-you-make-of-this/ . It is only about 23 minutes of arc northwest of Mu Cephi, Herschel's Garnet Star which is just out of the field's lower left corner. I tried including it but it sent glare across the image beyond belief and had to be moved off the chip. The planetary is listed as a galaxy in the PGC extended catalog as PGC as #2584974 at magnitude 16.8. I don't know if it has ever been seen visually in an amateur scope.

The cropped larger view of the planetary shows a faint blue star in the center just left of the bright blue streak running from the southern edge up past the center. This is likely the central star causing the planetary to glow mostly in OIII light though it seems rather blue to me for just OIII emission which is more cyan in color.

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

Related Designations for PN G100.4+04.6