ASTRO: CTB1 = Abell 85

Supernova remnant CTB1 (also classified as no. 85 in Abell's catalogue of
planetary nebulae) has been a rather popular object a few month ago in
several astro forums.
I imaged it in September, using my Skywatcher 80ED scope with a Celestron
f/6.3 SCT-reducer to get a sufficient field of view. I had Halpha data from
two nights with different optical configurations (once with filter wheel,
once without), which not only gave different scales but also a slightly
different geometry (distortion) of the image, so adding both nights hurt
star shapes a bit.
Also it probably would have been better to use a narrower Halpha filter (I
used the 13nm Astronomik, the 7nm Baader does not fit into my very slim
filter wheel) to get better contrast and keep stars back a bit.
I also have one hour of OIII data, didn't get more because I could not see
anything in the single raw frames. I should have continued the series as I
can see parts of the nebula in the stacked OIII frames.

Taken from the middle of Berlin with a Skywatcher 80ED at f/5 on a G11
mount, SXV-H9 camera, 43x10 minutes for Halpha, 5x5 minutes for green and
blue, combined to a Ha:Ha:G:B image.

The picture can also be found at
http://ccd-astronomy.de/temp/Abell85-CTB1-colourgut.jpg

Stefan

I'd have not expected you to be able to image the whole bubble from your
location. Amazing job and great color. I do need to add a small scope
for such objects.

Next you'll be doing that new possible planetary or whatever bubble near
the Crescent Nebula.

Rick



Stefan Lilge wrote:

Supernova remnant CTB1 (also classified as no. 85 in Abell's catalogue of
planetary nebulae) has been a rather popular object a few month ago in
several astro forums.
I imaged it in September, using my Skywatcher 80ED scope with a Celestron
f/6.3 SCT-reducer to get a sufficient field of view. I had Halpha data from
two nights with different optical configurations (once with filter wheel,
once without), which not only gave different scales but also a slightly
different geometry (distortion) of the image, so adding both nights hurt
star shapes a bit.
Also it probably would have been better to use a narrower Halpha filter (I
used the 13nm Astronomik, the 7nm Baader does not fit into my very slim
filter wheel) to get better contrast and keep stars back a bit.
I also have one hour of OIII data, didn't get more because I could not see
anything in the single raw frames. I should have continued the series as I
can see parts of the nebula in the stacked OIII frames.

Taken from the middle of Berlin with a Skywatcher 80ED at f/5 on a G11
mount, SXV-H9 camera, 43x10 minutes for Halpha, 5x5 minutes for green and
blue, combined to a Ha:Ha:G:B image.

The picture can also be found at
http://ccd-astronomy.de/temp/Abell85-CTB1-colourgut.jpg

Stefan




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