ASTRO: FGC 163 and friends

FGC 163, also known as NGC 522 is another flat galaxy I had on my to-do
list. To make the FGC catalog the galaxy's disk must be at least 8
times that of its central bulge. These galaxies tend to not only be
flat but have small to negligible central bulges.

Unfortunately the night was horrible. south winds of 65kph (40mph) were
blowing but thanks to the wind being from the south I didn't have much
worry about branches coming my way so gave it a try anyway. Skies were
horribly bright. My normal background is about 400 ADU in a 10 minute
frame. It was over 2000 or over 5 times normal this night and
transparency awful. But not having imaging weather for a while I had to
try. The result is pretty poor. Maybe the worst image I've posted.
There were three galaxy clusters in the field I'd hoped to bring out as
they are rather rich but since only one or two members of each got
through the gunk I didn't bother showing them. Normally a magnitude
18.8 asteroid would be quite bright and show color trails before or
after the luminance trail but that didn't happen. I think I lost 2.5
magnitudes or more.

FGC 163 is located in eastern Pisces. Redshift puts it about 110
million light-years distant though Tully Fisher measurement say 160
million light-years. If the 110 million light-year distance is correct
it is about 75,000 light-years in diameter. If the more distant is
right it is 105,000 light-years across. Either are reasonable. With IC
101 showing about the same redshift I'll vote that the 110 million
light-year distance is more likely the case. Unfortunately there is no
other distance measurement for IC 101.

There's a little galaxy peeking out of the eastern side of FGC 163 but I
found no catalog entry for it in NED. In fact many galaxies show now
entries in NED and only a few have redshift data. All that NED lists
are shown in the annotate image. Those few NED classified have that on
the annotated image as well. In the case of NGC 163 the NGC project
says Sbc: while NED say Sc one place and Sbc: another. I put both on
the annotated image. It is so edge on this discrepancy is not unexpected.

There are several asteroids in the image that normally would have come
through quite strongly. Conditions were so poor only one came through
and it is quiet weak. I've marked only it on the annotated image to the
upper right. I'd estimate I lost over 2 magnitudes to sky conditions.
While normally I handle high winds well the stars are somewhat elongated
by the winds this time. A roll off roof can catch wind rather well
sometimes. This was one of those times. Also blue frames were hit hard
by lowering transparency and only half the intensity of the red frame
with the green frames both nearly twice that of red. This wide
difference makes color balance difficult as the blue frames picked up no
faint features seen by the red and especially the green frames. This
likely cost me a lot of blue in the disks of the many distant disk
galaxies in the image. Consider the color data somewhat suspect. Star
shapes were horrid. No star looked like its neighbor. They had flares,
elongated on any of 180 degrees, etc. I tried a few tricks to round
them out. Some rounded rather well when only slightly off round. The
rest look better than they did but are still rather poor.

While the data is as low as any I've tried to process it is far better
than the dozens I've had to throw out entirely in 2012-2013 so far.
Really been a bad 18 months for imaging here. No improvement is sight
either. For now it too is added to the reshoot list.

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

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

Rick,

that's a delicate small thing. I tried not to look at it too hard, otherwise
it might break ;-)

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

FGC 163, also known as NGC 522 is another flat galaxy I had on my to-do
list. To make the FGC catalog the galaxy's disk must be at least 8
times that of its central bulge. These galaxies tend to not only be
flat but have small to negligible central bulges.

Unfortunately the night was horrible. south winds of 65kph (40mph) were
blowing but thanks to the wind being from the south I didn't have much
worry about branches coming my way so gave it a try anyway. Skies were
horribly bright. My normal background is about 400 ADU in a 10 minute
frame. It was over 2000 or over 5 times normal this night and
transparency awful. But not having imaging weather for a while I had to
try. The result is pretty poor. Maybe the worst image I've posted.
There were three galaxy clusters in the field I'd hoped to bring out as
they are rather rich but since only one or two members of each got
through the gunk I didn't bother showing them. Normally a magnitude
18.8 asteroid would be quite bright and show color trails before or
after the luminance trail but that didn't happen. I think I lost 2.5
magnitudes or more.

FGC 163 is located in eastern Pisces. Redshift puts it about 110
million light-years distant though Tully Fisher measurement say 160
million light-years. If the 110 million light-year distance is correct
it is about 75,000 light-years in diameter. If the more distant is
right it is 105,000 light-years across. Either are reasonable. With IC
101 showing about the same redshift I'll vote that the 110 million
light-year distance is more likely the case. Unfortunately there is no
other distance measurement for IC 101.

There's a little galaxy peeking out of the eastern side of FGC 163 but I
found no catalog entry for it in NED. In fact many galaxies show now
entries in NED and only a few have redshift data. All that NED lists
are shown in the annotate image. Those few NED classified have that on
the annotated image as well. In the case of NGC 163 the NGC project
says Sbc: while NED say Sc one place and Sbc: another. I put both on
the annotated image. It is so edge on this discrepancy is not unexpected.

There are several asteroids in the image that normally would have come
through quite strongly. Conditions were so poor only one came through
and it is quiet weak. I've marked only it on the annotated image to the
upper right. I'd estimate I lost over 2 magnitudes to sky conditions.
While normally I handle high winds well the stars are somewhat elongated
by the winds this time. A roll off roof can catch wind rather well
sometimes. This was one of those times. Also blue frames were hit hard
by lowering transparency and only half the intensity of the red frame
with the green frames both nearly twice that of red. This wide
difference makes color balance difficult as the blue frames picked up no
faint features seen by the red and especially the green frames. This
likely cost me a lot of blue in the disks of the many distant disk
galaxies in the image. Consider the color data somewhat suspect. Star
shapes were horrid. No star looked like its neighbor. They had flares,
elongated on any of 180 degrees, etc. I tried a few tricks to round
them out. Some rounded rather well when only slightly off round. The
rest look better than they did but are still rather poor.

While the data is as low as any I've tried to process it is far better
than the dozens I've had to throw out entirely in 2012-2013 so far.
Really been a bad 18 months for imaging here. No improvement is sight
either. For now it too is added to the reshoot list.

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

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