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I own a Vixen ED-80 refractor which is used with a custom focuser by Telescope Service.

(pictured below)

A Celestron f/6 SCT reducer corrector did not provide decent images either because it is not appropriate or because I did not maintain the correct distance. 

I am thinking of buying the Sky-Watcher .85x Reducer/Flattener instead, as it is made for similar ED80 telescopes. 

I do not know what is the correct distance of the SkyWatcher reducer for my setup and more important, I do not know if it will focus with the custom TS focuser.

Do you have any similar setup that you have used successfully?

Clear Skies!



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Hi @Stardweller,

From what I have read, I believe you have just answered your question.

The SCT is a catadioptric and the field flattener/focal reducer, (FF/FR), is purely meant for those made by Celestron, Meade and other brands. I have used mine on my 're-modded' Meade ETX105, (see below), purely as an extension when using the Crayford focusser. Without it the focus wheel/knob of the ETX gets in the way of the locking collar and I am unable to attach it. I can attach the diagonal without it.

PIC023.JPG.9015768a3cb121416d49ca9a58c896aa.JPG<--- My ETX105 with Celestron FF/FR and Crayford focusser...

PIC022.JPG.ad2dde5173f39613817eb9f4f768708c.JPG<--- with a 2" star diagonal...

PIC021.JPG.317e3ab5bc2a32848d576782c9caf3ab.JPG<--- and without the FF/FR.

I do have an SCT threaded skylight [#1A] filter which does give me enough space and slightly reduced weight to fit the Crayford focusser without the stock focus wheel/knob getting in the way. That said, I am still looking for a lighter weight extension ring.  

Edited by Philip R

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