Anyone every use a spotting scope for an autoguider? Not sure why it wouldn't be more in use, I mean, 80 mm APO, light, F6, 1.25" eyepeice. Why wouldn't someone use for instance one of the celestron spotting scopes?
I'm thinking it might be that it can be manipulated in the software. Or if you really wanted to get fancy pants you could cross the wires in the cable going from guider to mount.
Honestly, all you need out of a guide scope is that you can stick the camera into it and get it to focus on astronomic targets. Everything else about image orientation and the likes is handled by the software when you "calibrate" the guider. This is especially true about PHD or MaximDL, these will calibrate to any guidescope with any "optical plumbing" in the way.
So when you choose your spotting scope, pick one you can take the eyepiece out of. The rest doesn't matter.
PS: spotting scopes typically have a 45deg erecting prism in them so that terrestrial targets aren't upside down. I got a 102mm spotter that I use to guide now and it came with a removable 45degree prism. The only slight problem there is that the prism may have a seam in the middle of it like mine has in which case you don't want to guide on a star close to center of the view.
My spotting scope is a discontinued celestron 102mm f/5. The thing shows massive chromatic aberration (i saw it on the guider before I put an IR filter on) but as far as a guider goes its' great.
In the pics i posted about my "balcony observatory" it's the black scope on the bottom.