Quote:
Originally Posted by morls
Hi Don, the main reason is because I want to have finer control than I can get with the internal focuser, and the elimination of mirror shift will be a bonus as well.
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Then replace the focuser with a Starlight Instruments 2-speed focuser replacement or add the JMI 2-speed add on. Both of those give you very fine control without adding focal length to the scope.
For every 10mm of additional rear length you add, you add 31mm to the focal length of the scope. You'll end up with an even longer focal ratio than the long f/ratio the scope already has.
Your scope already has a narrow field of view; you probably don't want to make it even narrower.