Saturday, March 24, 2012

Imaging with my 8" SCT

I felt just like a bear coming out of hibernation yesterday. For the first time in many months a group of friends joined me up on Mount Seymour for a great night of stargazing. I had a hard time deciding whether or not I was going to use my 8" Schmidt-Cassengrain telescope or my 2.5" Refractor.  After much thought I settled on the 8" telescope simply because I haven't had much of a chance to use it for imaging.

Ironically most of the pictures I've taken have been through my much smaller (although much nicer!) TV85. However I wanted to get some practice imaging with a long focal length so  I packed up the 8" and dragged it up to the mountain. The results were encouraging but not stellar (no pun intended) mostly because the freezing temperatures drained my computer battery and stalled my imaging session. I started out trying to image a faint group of galaxies called the Hickson 44 group. 

Given that the galaxies in this image are rather faint (the brightest one is magnitude 11.4) and I took about 1/10 the exposures that I wanted to I'm relatively pleased.  The focus and tracking were both pretty good.  However I did realise two things; first there is something on either my camera or my telescope because I can see some dark spots that are obviously not part of the picture.  Second its obvious that my SCT is not designed for photography; The field is curved and only the center of the field is suitable for photography. That being said I'm still pretty happy since this is my first serious attempt at using my SCT for imaging.

The second image I took was sort of ad hoc. I wasn't planning on shooting anything in Ursa Major but because of the way the light pollution from the city and the ski hill were working it was the only place there was dark sky.  Again, I got about 1/10 the exposures I needed but it just confirmed that my SCT can be used but not particularly well.

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