Thread: Gso rc 200mm question
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Old 11-07-2014, 02:20 PM
pjphilli (Peter)
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Join Date: Jan 2008
Location: Thornleigh Sydney
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Gso rc 200mm question
Hi

When I was cleaning the mirrors of my GSO 200mm RC scope I noticed that the secondary mirror has a black spot marked in its centre. What is the purpose/use of this black spot?

Cheers Peter
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