The 102mm is a bit too long to piggyback on the Dob, but the short tube 80 or 90mm would make a great finder. I've been meaning to buy a right angle finder anyway. Just got to work out what's the most cost effective option. The ED80 has an oversized 4" OTA, so the tube rings of the smaller scopes would not fit it.
Got a quote for EQ5 + tube rings from AOE: $548. So that's just $51 extra for the 4" f/10 + accessories. I read several reviews about 100-105mm f10 Chinese achromats, and the general impression I got is that this sort of scope at best could equal the ED80 on some targets and would be inferior on others. I wonder what the resale value of the 102mm OTA would be.
