You must differentiate imaging from visual. A visual reflector can get by with a tiny secondary obstruction. And even an 8" APO refractor isn't going to cut it for the really faint fuzzies, visually. That said, I agree with you 100% where imaging is concerned. That's the reason I bought my 80mm and 100mm EDs. Even a 120mm ED scope is a chunk of change ($1.5K-ish), although the prices have been dropping lately (someone please tell TeleVue...lol) On Tue, Mar 23, 2010 at 12:54 PM, David Rankin <David@rankinstudio.com>wrote:
I think they are sweet scopes. It's just a bummer they get so expensive over 120mm. They also don't have the 30% + obstruction of the primary element, and having no secondary elements eliminates optical alignment problems. I think this is why smaller apo's have a better astrophotography reputation than medium/larger reflectors.
Mike Clemens posts on the cloudy nights dslr imaging forums. He shoots with a TEC200mm F9 ED refractor. The images he captures are amazing.
http://www.pbase.com/mclemens1969/galaxies
If I had the funds, I would switch to a 150mm apo in a heartbeat.