PST Mod

[Carabela]

What is the purpose of using a SCT focuser for a PST Mod and why can't I use a 2" Crayford Focusers for refractors instead?

[Carabela]

If a SCT must be used then what adapter should I use to attach it to a 80mm Vixen?

[swisswalter]

Hi Chris

you can use any focuser, but using the sct focuser let you attache the end of the PST directly to it

[Merlin66]

Depending on your set-up, you can use any focuser. The 2" fitting is normally used in conjunction with a 2" nosepiece adaptor on the PST etalon. Infact, you can use a "spacer" rather than a focuser to hold the etalon....once it is positioned correctly (at the majic 200mm inside prime focus) it NEVER moves.
What is required is a focuser after the etalon, between it and the camera/ eyepiece. This final focus will be 200mm behind the etalon. I, and others, use a Borg helical focuser in this position.
Hope this helps.

[solarchat]

I moved this to the scope mods section..