Observing Log for Mike Durkin
I wanted to test out and see if I could use the Bower 500mm catadioptric lens for
DSLR photometry. I decided to use AG Dra as my target since according to the
AAVSO data, it should be somewhere around magnitude 9.5-9.6, which is about the
magnitude that I think this lens might be good for. Since the field of view is
fairly tight, roughly 1-2 degrees, it took me about an hour to get the star
centered. I had to star hop Kochab in UMi, since that was bright enough to
show up in live preview.
Testing tonight to see how well the tracking of the Star Adventurer
out would do with a lens at 300mm. It seems that at 300mm, I would probably
have to discard about 1/4 to 1/2 of the total frames, which is a bit more
than I woud like. The exposure limit for my lens at 300mm is about 45 seconds
to 1 minute. The area I focused on was M31, but towards the end I kicked
one of the tripod legs a little and didn't bother trying to find it in the field
of view again. I am wondering if for the Star Adventurer mount I should limit
myself to 200mm, unless I want to do 30-45 seconds as a limit for the light
frames.
It has been a year exactly since my last DSLR photometry session, and like
last year I measured P Cyg and VV Cep. Last year I measured CH Cyg as well,
but I did not have time for that. I also wanted to test out the 500mm lens
for photometry, but I did not get time for that either.
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