Refractor focal reducer help

[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.

[gbeal]

Really, unless you find someone with the exact same scope, and exact same reducer, can you tell. Best bet is to try them, only way for me.
I have used a variety of refractors with the TRF2008, works great, and also the AT2FF (flattener only, not a reducer).
But as our American cousins say YMMV.
Gary

[LewisM]

Bought the Orion 0.8X refractor reducer for $145 today at Sirius Optics in Brisbane, so we shall see how that goes tonight on the ED100. Doesn't reduce it MUCH (from f/9 to f/7.2), but should be a big improvement. Be interesting to put it on the ED80... that would go from f/7.5 to f/6... not much in it :)

[cometcatcher]

The Orion reducer, is it also a flattener or reducer only? I have the Orion field flattener without reducer.

It seems strange that Orion would make one of each but not a combo?