Hey John,
I know its an older thread but I thought I'd chime in my opinion too
As Poita said, I was very lucky to have the lodestar borrowed to try it out on my RC8 as an OAG. Here are my thoughts on the Lodestar, and OAG in general (See the second last post) -
http://www.iceinspace.com.au/forum/s...d.php?t=102001. In essence, I just wish I shelled out the $600 and bought it in the first place. Its one of those things what no matter what imaging train you use, this thing is practically guaranteed to give you stars. I mean the RC8 has a 50% secondary and even though its a F/8 (1600mm) I *always* found a guidestar.
In your case it's a f/5 so I personally think you *might* be able to get away with the QHY5L-II or the likes since you wont have such dim stars. But I know that at 1600mm with my RC8 the FOV is severely restricted so chances of finding a bright star no matter where in the sky you point is also slim. Also I think at 1600mm you'd be hardpressed to guide with a guidescope. A good OAG costs ~$200; the ST80 is more expensive. A QHY5L-II costs $320. So its not that expensive to go OAG. If it doesnt work worst case sell the QHY5L-II for $40 cheaper (Since its so new and still in demand) and then get the lodestar. A $40 or so loss isnt that big a deal I personally think to have known first hand you tried with a cheaper guidecam
food for thought.