The Antares 0.5x FR is inserted into the imaging train as would a 2" filter. Different spacing can be used to achieve various reductions factors, as described on the vendor web site, seen here - http://agenaastro.com/antares-2-0-5x-focal-reducer.html

I have also used the reducer visually with a NexStar 8SE and it is very acceptable for that purpose. In fact, I inserted a 1/2 inch spacer between the eyepiece bottom (23mm Celestron Axiom LX) and the reducer and got very good views of nearly 2 degrees, encompassing most of M31, The Andromeda Galaxy, and nearly all of M45, The Pleides. Although not as convenient as a reducer that mounts to the rear cell of an SCT, for the price, I feel it's a keeper. I have also mounted it in an eyepiece adapter so it can be used with any eyepiece.

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