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Old 06-06-2020, 09:34 PM
Sitt (Simon)
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Join Date: Jul 2007
Location: Perth
Posts: 34
Back focus issue

I have a Skywatcher Espirit 120 that I'm having back focus issues with. I've read numerous sites and read the Espirit instructions over but having difficulty getting focus for some reason when used with a Celestron OAG with a filter drawer.
Everything I've read says 75mm back focus from start of the threads on the end of the reducer to the sensor. I obtained focus this afternoon playing with various adapters and managed to get focus on a house around 1km away with 100mm back spacing. Yet to test 100mm out on the stars but I think this spacing is going to cause me issues.
Any pointers?
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