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ASTRO: NGC 2841 A flocculent galaxy
NGC 2871 is a flocculent galaxy in Ursa Major that reminds me of M63
with its tufts of star clouds rather than defined arms. The distance to this one is rather vague. I've seen estimates from 45 to 80 million light years. Red shift and Cepheid measurements favor the shorter estimate while Tulley-Fisher measurements and a type 1a super nova estimate put it further away. Considering large earth based scopes have resolved a few stars in it I'd favor the shorter estimates. Hubble easily resolves it into stars. Though there's no published Hubble image, you can see some good examples at the Hubble Legacy Archive. NED classes it a SA(r)b:;LINER Sy1 indicating it has a very active nucleus. The NGC project takes the simple route with Sb I as its classification. While the Arp Atlas of Peculiar Galaxies has been my main target of late I'm also working on the objects in the Astronomical League's Herschel 400 list from the early 80's. This was one of the nicer ones in that list. One that deserves more attention than most astrophotographers give it. The eastern (left) side appears to be the side closest to us. The flocculent nature of the west side is somewhat hidden by what appears to be a gauze of halo stars. Though after a pass through the high pass filter this difference was greatly reduced. There are a lot of background galaxies so I prepared an annotated version. One object is considered a quasar in some catalogs and a just a galaxy with a strong AGN by another. Looking at the PSF in my image it is that of an extended object rather than a point source so it appears I'm picking up some of the galaxy the quasar is in. Not all that common but considering it is only about 2.44 billion light years distant not surprising. It is labeled as Q/G in the annotated image since more catalogs say quasar than galaxy. The brightest background galaxy in the image is CGCG 265-009. I found no attempt to classify this odd blue galaxy. It looks like a two armed barred spiral with lots of disconnected star clouds in the disk unrelated to the arms. It would seem to fit somewhere in Arp's atlas of peculiar galaxies.ASTRO: NGC 2841 A flocculent galaxy The Sloan image of NGC 2841 is at: http://astronomerica.awardspace.com/SDSS-19/NGC2841.php It doesn't show the flocculent nature very well, probably because of its heavy weighting toward IR light. The dark line is the gap between the CCDs that make up its imaging array. 14" LX200R @ f/10, L=6x10', RGB=2x10'x3, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
#2
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ASTRO: NGC 2841 A flocculent galaxy
I imaged this one in 2005 and overexeposed the core when processing.
Need to revisit (so many galaxies, so little time). Last evening was prefect but unfortunately house was filled with family, in-laws and out-laws so all I could do was cast wistul glances towards the western sky as the soon slowly set silhouetting the costal range in sharp detail. Oh well, forecast indicates a chance for clear skys next Tuesday. On Sat, 20 Nov 2010 15:36:30 -0600, Rick Johnson wrote: NGC 2871 is a flocculent galaxy in Ursa Major that reminds me of M63 with its tufts of star clouds rather than defined arms. The distance to this one is rather vague. I've seen estimates from 45 to 80 million light years. Red shift and Cepheid measurements favor the shorter estimate while Tulley-Fisher measurements and a type 1a super nova estimate put it further away. Considering large earth based scopes have resolved a few stars in it I'd favor the shorter estimates. Hubble easily resolves it into stars. Though there's no published Hubble image, you can see some good examples at the Hubble Legacy Archive. NED classes it a SA(r)b:;LINER Sy1 indicating it has a very active nucleus. The NGC project takes the simple route with Sb I as its classification. While the Arp Atlas of Peculiar Galaxies has been my main target of late I'm also working on the objects in the Astronomical League's Herschel 400 list from the early 80's. This was one of the nicer ones in that list. One that deserves more attention than most astrophotographers give it. The eastern (left) side appears to be the side closest to us. The flocculent nature of the west side is somewhat hidden by what appears to be a gauze of halo stars. Though after a pass through the high pass filter this difference was greatly reduced. There are a lot of background galaxies so I prepared an annotated version. One object is considered a quasar in some catalogs and a just a galaxy with a strong AGN by another. Looking at the PSF in my image it is that of an extended object rather than a point source so it appears I'm picking up some of the galaxy the quasar is in. Not all that common but considering it is only about 2.44 billion light years distant not surprising. It is labeled as Q/G in the annotated image since more catalogs say quasar than galaxy. The brightest background galaxy in the image is CGCG 265-009. I found no attempt to classify this odd blue galaxy. It looks like a two armed barred spiral with lots of disconnected star clouds in the disk unrelated to the arms. It would seem to fit somewhere in Arp's atlas of peculiar galaxies.ASTRO: NGC 2841 A flocculent galaxy The Sloan image of NGC 2841 is at: http://astronomerica.awardspace.com/SDSS-19/NGC2841.php It doesn't show the flocculent nature very well, probably because of its heavy weighting toward IR light. The dark line is the gap between the CCDs that make up its imaging array. 14" LX200R @ f/10, L=6x10', RGB=2x10'x3, STL-11000XM, Paramount ME Rick |
#3
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ASTRO: NGC 2841 A flocculent galaxy
Moonrise would soon have put an end to it anyway. Snow here.
Of course when you automated I just have to get away long enough to hit the button to open the roof. Then two hours later when it is dark I just start the imaging script running and go back to dinner or whatever. Spent the afternoon clearing drifting snow off the one km drive out to a township road (which has drifted shut thanks to their not spending any money to clear it. I may end up doing 3 more km of snow blowing. Rick On 11/26/2010 3:06 PM, glen youman wrote: I imaged this one in 2005 and overexeposed the core when processing. Need to revisit (so many galaxies, so little time). Last evening was prefect but unfortunately house was filled with family, in-laws and out-laws so all I could do was cast wistul glances towards the western sky as the soon slowly set silhouetting the costal range in sharp detail. Oh well, forecast indicates a chance for clear skys next Tuesday. On Sat, 20 Nov 2010 15:36:30 -0600, Rick wrote: NGC 2871 is a flocculent galaxy in Ursa Major that reminds me of M63 with its tufts of star clouds rather than defined arms. The distance to this one is rather vague. I've seen estimates from 45 to 80 million light years. Red shift and Cepheid measurements favor the shorter estimate while Tulley-Fisher measurements and a type 1a super nova estimate put it further away. Considering large earth based scopes have resolved a few stars in it I'd favor the shorter estimates. Hubble easily resolves it into stars. Though there's no published Hubble image, you can see some good examples at the Hubble Legacy Archive. NED classes it a SA(r)b:;LINER Sy1 indicating it has a very active nucleus. The NGC project takes the simple route with Sb I as its classification. While the Arp Atlas of Peculiar Galaxies has been my main target of late I'm also working on the objects in the Astronomical League's Herschel 400 list from the early 80's. This was one of the nicer ones in that list. One that deserves more attention than most astrophotographers give it. The eastern (left) side appears to be the side closest to us. The flocculent nature of the west side is somewhat hidden by what appears to be a gauze of halo stars. Though after a pass through the high pass filter this difference was greatly reduced. There are a lot of background galaxies so I prepared an annotated version. One object is considered a quasar in some catalogs and a just a galaxy with a strong AGN by another. Looking at the PSF in my image it is that of an extended object rather than a point source so it appears I'm picking up some of the galaxy the quasar is in. Not all that common but considering it is only about 2.44 billion light years distant not surprising. It is labeled as Q/G in the annotated image since more catalogs say quasar than galaxy. The brightest background galaxy in the image is CGCG 265-009. I found no attempt to classify this odd blue galaxy. It looks like a two armed barred spiral with lots of disconnected star clouds in the disk unrelated to the arms. It would seem to fit somewhere in Arp's atlas of peculiar galaxies.ASTRO: NGC 2841 A flocculent galaxy The Sloan image of NGC 2841 is at: http://astronomerica.awardspace.com/SDSS-19/NGC2841.php It doesn't show the flocculent nature very well, probably because of its heavy weighting toward IR light. The dark line is the gap between the CCDs that make up its imaging array. 14" LX200R @ f/10, L=6x10', RGB=2x10'x3, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
#4
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ASTRO: NGC 2841 A flocculent galaxy
Excellent picture Rick. It is very difficult to achieve the level of detail
of your image. In bad seeing this galaxy can look quite boring... Stefan "Rick Johnson" schrieb im Newsbeitrag ster.com... NGC 2871 is a flocculent galaxy in Ursa Major that reminds me of M63 with its tufts of star clouds rather than defined arms. The distance to this one is rather vague. I've seen estimates from 45 to 80 million light years. Red shift and Cepheid measurements favor the shorter estimate while Tulley-Fisher measurements and a type 1a super nova estimate put it further away. Considering large earth based scopes have resolved a few stars in it I'd favor the shorter estimates. Hubble easily resolves it into stars. Though there's no published Hubble image, you can see some good examples at the Hubble Legacy Archive. NED classes it a SA(r)b:;LINER Sy1 indicating it has a very active nucleus. The NGC project takes the simple route with Sb I as its classification. While the Arp Atlas of Peculiar Galaxies has been my main target of late I'm also working on the objects in the Astronomical League's Herschel 400 list from the early 80's. This was one of the nicer ones in that list. One that deserves more attention than most astrophotographers give it. The eastern (left) side appears to be the side closest to us. The flocculent nature of the west side is somewhat hidden by what appears to be a gauze of halo stars. Though after a pass through the high pass filter this difference was greatly reduced. There are a lot of background galaxies so I prepared an annotated version. One object is considered a quasar in some catalogs and a just a galaxy with a strong AGN by another. Looking at the PSF in my image it is that of an extended object rather than a point source so it appears I'm picking up some of the galaxy the quasar is in. Not all that common but considering it is only about 2.44 billion light years distant not surprising. It is labeled as Q/G in the annotated image since more catalogs say quasar than galaxy. The brightest background galaxy in the image is CGCG 265-009. I found no attempt to classify this odd blue galaxy. It looks like a two armed barred spiral with lots of disconnected star clouds in the disk unrelated to the arms. It would seem to fit somewhere in Arp's atlas of peculiar galaxies.ASTRO: NGC 2841 A flocculent galaxy The Sloan image of NGC 2841 is at: http://astronomerica.awardspace.com/SDSS-19/NGC2841.php It doesn't show the flocculent nature very well, probably because of its heavy weighting toward IR light. The dark line is the gap between the CCDs that make up its imaging array. 14" LX200R @ f/10, L=6x10', RGB=2x10'x3, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
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