ASTRO: 23rd Magnitude and beyond!

The weather has been awful for the last 10 months. My todo list is
growing far faster than the weather has allowed me to reduce it. Ever
since I built the observatory I've had one target I always figured was
beyond its ability but I was bound and determined to try if conditions
ever allowed. They never did. Until this new moon. After 10 clouded
out new moons I had a clear one. Not only that it was the steadiest
seeing I've ever had. And my goal was just crossing the meridian at the
end of astronomical twilight. What could be more perfect. I gathered 2
hours of the most fantastic data I've ever captured. FWHM was down to
1.1" of arc! I was super excited. So excited I never noticed AutoSave
was turned off!! It all went in the bit bucket. By now the target was
lower in the sky and seeing had fallen to 1.5" but I did get two more 20
minute frames with autosave one. Over the next two nights I got a bit
more Lum data, not what I lost however.

What I was imaging was Abell 2218. It is quite famous. It has more
mass packed into a small space than most galaxy clusters so was one of
the first places astronomers looked for gravitational lensing. Sure
enough, when the big scopes looked at the cluster at high resolution
some were seen. My question was whether an amateur observatory like
mine not located on a mountain with laminar air flow could image this.
Considering the arcs were mostly 23rd magnitude and fainter plus were
less than a second of arc wide it seemed a pipe dream.

The first photo is the cluster at my normal 1" of arc per pixel. No
arcs are seen. But with seeing so good I did the imaging at 0.5" per
pixel. Then I blew that up to 0.25" per pixel. That's the second
image. It is grainy due to the lack of exposure time but seeing at the
needed level happens here only once in 3 years and I lost the 6 best
frames! So we'll have to go with this. In a separate post I've put ID
on some of the arcs. Some are 24th magnitude according to NED!

The big blue galaxy is UGCA 413 at magnitude 14.68 and is only about 320
million light years away. Abell 2218 is 2.07 billion light years away
light travel time. More on the lensed galaxies in the next post.

14" LX200R @ f/10, L=6x20' binned 1x1, RGB=2x20' binned 2x2,
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".

WOW!!! That is deep!

Joe


"Rick Johnson" wrote in message
om...
The weather has been awful for the last 10 months. My todo list is
growing far faster than the weather has allowed me to reduce it. Ever
since I built the observatory I've had one target I always figured was
beyond its ability but I was bound and determined to try if conditions
ever allowed. They never did. Until this new moon. After 10 clouded
out new moons I had a clear one. Not only that it was the steadiest
seeing I've ever had. And my goal was just crossing the meridian at the
end of astronomical twilight. What could be more perfect. I gathered 2
hours of the most fantastic data I've ever captured. FWHM was down to
1.1" of arc! I was super excited. So excited I never noticed AutoSave
was turned off!! It all went in the bit bucket. By now the target was
lower in the sky and seeing had fallen to 1.5" but I did get two more 20
minute frames with autosave one. Over the next two nights I got a bit
more Lum data, not what I lost however.

What I was imaging was Abell 2218. It is quite famous. It has more
mass packed into a small space than most galaxy clusters so was one of
the first places astronomers looked for gravitational lensing. Sure
enough, when the big scopes looked at the cluster at high resolution
some were seen. My question was whether an amateur observatory like
mine not located on a mountain with laminar air flow could image this.
Considering the arcs were mostly 23rd magnitude and fainter plus were
less than a second of arc wide it seemed a pipe dream.

The first photo is the cluster at my normal 1" of arc per pixel. No
arcs are seen. But with seeing so good I did the imaging at 0.5" per
pixel. Then I blew that up to 0.25" per pixel. That's the second
image. It is grainy due to the lack of exposure time but seeing at the
needed level happens here only once in 3 years and I lost the 6 best
frames! So we'll have to go with this. In a separate post I've put ID
on some of the arcs. Some are 24th magnitude according to NED!

The big blue galaxy is UGCA 413 at magnitude 14.68 and is only about 320
million light years away. Abell 2218 is 2.07 billion light years away
light travel time. More on the lensed galaxies in the next post.

14" LX200R @ f/10, L=6x20' binned 1x1, RGB=2x20' binned 2x2,
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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Nice work Rick!

Rick Johnson wrote:

What I was imaging was Abell 2218. It is quite famous. It has more
mass packed into a small space than most galaxy clusters so was one of
the first places astronomers looked for gravitational lensing.

John N. Gretchen III
N5JNG NCS304
http://www.tisd.net/~jng3