Old 05-09-2013, 08:53 AM
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graham.hobart (Graham stevens)

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Location: hobart, tasmania
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focal reducer for GSO RC8?

Does anybody use a reducer on a GSO Rc 8?
If so which one and is it any good?
What spacings does you use with the camera?
I am interested in the Astro Physics on on the Teleskop_Servic website but would appreciate any thoughts
Would be using it with a QSI 683 and or a DSLR.
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Old 05-09-2013, 06:27 PM
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naskies (Dave)
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Location: Brisbane
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I've used an AP CCDT67 successfully on my RC8:


My STF-8300M + FW + OAG + Baader 2" nosepiece places the image plane at 85 mm behind the reducer, giving exactly 0.67x reduction, i.e. f/5.36. The image circle is small though - you definitely can't use it with a full frame DSLR.

This reducer consumes a lot of back focus - with the reducer attached, I only needed one 25 mm extension tube behind my RC8 (with a 2" Moonlite focuser).

There wasn't enough back focus for my adaptive optics unit, so I stopped using the reducer. I might look at using the AP 27TVPH reducer (much more generous with back focus) when I can afford to upgrade to a larger focuser.
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