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ASTRO: Aquarius Dwarf



 
 
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  #1  
Old September 21st 12, 07:05 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
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Posts: 3,085
Default ASTRO: Aquarius Dwarf

The Aquarius Dwarf is a very difficult target for me due to its low
declination and need for lots of exposure time. I wasn't able to get
but 8 image of it with seeing around 3" of arc. All other images were
during worse seeing. I got best result using 4 luminance, two blue and
one each of green and red to make a pseudo luminance channel and the 4
color image for the color data. I'll try again this year if seeing this
low cooperates which isn't all that likely.

There's a debate over its distance as well as to it being a member of
the local group. It's redshift is negative making that of no use though
this close it wouldn't help either way. The latest measurements using
the Tip of the Red Giant Branch stars in the galaxy put it about 3.1
million light years distant. At its direction that would put it in the
local group. It is classed as IB(s)m. To me it is a smudge. For a
resolved view see the HST image at
http://en.wikipedia.org/wiki/File:Aq...le_WikiSky.jpg .
It is a rather raw image not cleaned of cosmic ray hits. Also many
stars seem to have dark holes in their center or break up into a ring of
pixels when seen at the highest resolution. I didn't try to process my
own version. Orientation is north at the top same as my image.

I didn't prepare an annotated image as this one is pretty well out of
the area of most galactic surveys. Only one other galaxy in the image
has any redshift data. It is 2MASX J20475750-1258569, an IR galaxy
located in the lower left of the image. It is about 620 million
light-years distant by redshift measurements.

14" LX200R @ f/10, Pseudo L=8x10' RG=1x10' B=2x10', STL-11000XM,
Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

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  #2  
Old September 24th 12, 09:58 PM posted to alt.binaries.pictures.astro
Stefan Lilge
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Posts: 2,269
Default ASTRO: Aquarius Dwarf

Rick,

I had to take a good look, but it is definately there :-)

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

The Aquarius Dwarf is a very difficult target for me due to its low
declination and need for lots of exposure time. I wasn't able to get
but 8 image of it with seeing around 3" of arc. All other images were
during worse seeing. I got best result using 4 luminance, two blue and
one each of green and red to make a pseudo luminance channel and the 4
color image for the color data. I'll try again this year if seeing this
low cooperates which isn't all that likely.

There's a debate over its distance as well as to it being a member of
the local group. It's redshift is negative making that of no use though
this close it wouldn't help either way. The latest measurements using
the Tip of the Red Giant Branch stars in the galaxy put it about 3.1
million light years distant. At its direction that would put it in the
local group. It is classed as IB(s)m. To me it is a smudge. For a
resolved view see the HST image at
http://en.wikipedia.org/wiki/File:Aq...le_WikiSky.jpg .
It is a rather raw image not cleaned of cosmic ray hits. Also many
stars seem to have dark holes in their center or break up into a ring of
pixels when seen at the highest resolution. I didn't try to process my
own version. Orientation is north at the top same as my image.

I didn't prepare an annotated image as this one is pretty well out of
the area of most galactic surveys. Only one other galaxy in the image
has any redshift data. It is 2MASX J20475750-1258569, an IR galaxy
located in the lower left of the image. It is about 620 million
light-years distant by redshift measurements.

14" LX200R @ f/10, Pseudo L=8x10' RG=1x10' B=2x10', STL-11000XM,
Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

 




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