Quote:
Originally Posted by Atmos
It's more to do with image scale than focal length. For your camera something around the 1000mm range would be good. So a 8" F/5 or 10" F/4 or 12" F/3 
http://www.astrobin.com/full/287438/D/
This was shot at 677mm on a night of awful seeing. |
I remembered this article from way back which has a great nomogram showing the relationship between pixel size, focal length and image scale.
Interesting article as well.
http://www.skyandtelescope.com/astro...ocal-reducers/