Quote:
Originally Posted by Astro_Bot
Permit me to jump in with a similar question:
Cost aside, is an ED120, f/7.5, FL=900mm a better choice for a "rich field telescope" mostly for imaging but maybe some visual work as well? Is a 3 degree TFOV realistically achievable with an ED120? Or, is the ED80 quite sufficient for that purpose and greater 'bang for the buck'?
I note that the light-gathering power of an RC 8" is much greater that an ED80, so I'm wandering why the ED80 is so popular.
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Assuming a 0.8 flattener, APS-C chip and Andrews' prices:
BD-ED80 600mm f/7.5 gives you 158x106 arcmin for $899
GSO RC8 CF 1600mm f/8 gives you 58x39 arcmin for $1099
BD-ED120 900mm f/7.5 gives you 105x80 arcmin for $1999