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Non-typical Secondary mirror on 20" RC?

Fri Mar 23, 2018 3:43 pm

We recently discovered that the secondary mirror of our 20" RC has a hole that runs through the center. On the side of the secondary facing the primary there is a metal tube (for lack of a better description) that projects towards the primary (see pictures). My colleagues and I have not encountered this configuration before. We discovered this issue when attempting to collimate the telescope with a Takahashi scope, which has obviously not been successful. Apparently our telescope has had focus issues for as long as anyone at the University can remember and I'm curious if the secondary mirror could be contributing to this. Does anyone have any insight?
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Re: Non-typical Secondary mirror on 20" RC?

Fri Mar 23, 2018 4:20 pm


Does anyone have any insight?, Please

Re: Non-typical Secondary mirror on 20" RC?

Wed Mar 28, 2018 5:33 pm

I've never seen an RC telescope but know that the design of the secondary mirror is to eliminate coma.
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