[LewisM]

Got an f/9 100ED. Want to reduce it for astrophotography, and a bit uncertain how to proceed.

Orion offers a reducer SPECIFICALLY for the 100ED, with one lens being apo - this is a 0.85x reducer. They also offer a generic 0.8X refractor reducer. Both are the same price.

Then there is the GSO 0.5x reducer for a LOT less (like $80 less) - are these specifically Newtonian?

I will be using a 2" one - all photographic, no visual.

Never dabbled with reducers on a refractor, so don't know the ins and outs and appreciate the help.