ASTRO: NGC 278

NGC 278 is a brilliant, face on, flocculent spiral in southern
Cassiopeia about 6.5 degrees north of M31. That's about all I can find
on it that astronomers agree upon. Distance estimates range from 14.8
to 38.5 million light-years. Some, including NED and the NGC project
classify it as a barred spiral SAB(rs)b. Yet others say it is just Sb
adding: "Both optical and near-IR images indicate that this SAB galaxy
is not actually barred." Others point to the spiral structure being
traced to within 2" of the core which is either a point source or a 2"
diffuse disk depending on which paper you read. There's little
agreement on anything about this galaxy it seems. The spiral structure
while of high surface brightness (unusually high in fact) has a very
muted fuzzy look to it. I get the feeling I'm looking at it through a
thick fog. The spiral structure is surrounded by a diffuse reddish
disk. Or is it a sphere and this is what is creating the "foggy" look.
I did a lot of pushing to get the spiral structure to show. Still
there's a foggy look to the galaxy to my eye. Processing the very
bright spiral disk and the faint outer disk makes this one rather a
challenge as the brightness range is unusually high.

As to the distance issue; if the galaxy is only 14.8 million light-years
away then it is only 9500 light years across. That seems way too small
to me to have such ordered structure. Galaxies this small are usually
devoid of much recognizable structure. Even at the 38.5 million
light-years it is only about 25,000 light-years across. While that fits
its structure it seems unusually well behaved for such a small galaxy.

Conditions were poor for this image as noted by the broken trail of the
bright asteroid (45878) 2000 WX29 to the left and a bit down from NGC
278. The gap is due to clouds. Note too the very start of the trail is
the brightest portion (conditions were good when I started) then there's
a very short break and it continues fainter as the trail fades away. I
had to shut down for some time. Conditions did then looked rather good
so I started in. Note the start of the second trail is a bit brighter
than the rest indicating it again went somewhat downhill. Color data
was taken days later when the asteroid was long out of the field.
Seeing was well below average though this is quickly becoming the new
average unfortunately.

The only other galaxy in the image that NED had any redshift data on is
CGCG 550-017 below and a bit left of the start of the asteroid trail.
It's redshift puts it somewhat over a half billion light-years distant.
With only the two galaxies and one asteroid I didn't bother to prepare
an annotated image.

October was a rotten month for imaging. This was my last one of the
month. I'm glad to leave it. Next up was a much more successful November.

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

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

Rick,

at last an object I have imaged :-)
At first look I wondered about the stark contrast between the spiral arms
and the halo, but it looks similar in my image.

Stefan


"Rick Johnson" schrieb im Newsbeitrag
...

NGC 278 is a brilliant, face on, flocculent spiral in southern
Cassiopeia about 6.5 degrees north of M31. That's about all I can find
on it that astronomers agree upon. Distance estimates range from 14.8
to 38.5 million light-years. Some, including NED and the NGC project
classify it as a barred spiral SAB(rs)b. Yet others say it is just Sb
adding: "Both optical and near-IR images indicate that this SAB galaxy
is not actually barred." Others point to the spiral structure being
traced to within 2" of the core which is either a point source or a 2"
diffuse disk depending on which paper you read. There's little
agreement on anything about this galaxy it seems. The spiral structure
while of high surface brightness (unusually high in fact) has a very
muted fuzzy look to it. I get the feeling I'm looking at it through a
thick fog. The spiral structure is surrounded by a diffuse reddish
disk. Or is it a sphere and this is what is creating the "foggy" look.
I did a lot of pushing to get the spiral structure to show. Still
there's a foggy look to the galaxy to my eye. Processing the very
bright spiral disk and the faint outer disk makes this one rather a
challenge as the brightness range is unusually high.

As to the distance issue; if the galaxy is only 14.8 million light-years
away then it is only 9500 light years across. That seems way too small
to me to have such ordered structure. Galaxies this small are usually
devoid of much recognizable structure. Even at the 38.5 million
light-years it is only about 25,000 light-years across. While that fits
its structure it seems unusually well behaved for such a small galaxy.

Conditions were poor for this image as noted by the broken trail of the
bright asteroid (45878) 2000 WX29 to the left and a bit down from NGC
278. The gap is due to clouds. Note too the very start of the trail is
the brightest portion (conditions were good when I started) then there's
a very short break and it continues fainter as the trail fades away. I
had to shut down for some time. Conditions did then looked rather good
so I started in. Note the start of the second trail is a bit brighter
than the rest indicating it again went somewhat downhill. Color data
was taken days later when the asteroid was long out of the field.
Seeing was well below average though this is quickly becoming the new
average unfortunately.

The only other galaxy in the image that NED had any redshift data on is
CGCG 550-017 below and a bit left of the start of the asteroid trail.
It's redshift puts it somewhat over a half billion light-years distant.
With only the two galaxies and one asteroid I didn't bother to prepare
an annotated image.

October was a rotten month for imaging. This was my last one of the
month. I'm glad to leave it. Next up was a much more successful November.

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

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