Author Topic: Optical Quality of Coulter 13.1 Inch Mirrors?  (Read 232 times)

rennlispuring

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Re: Optical Quality of Coulter 13.1 Inch Mirrors?
« Reply #15 on: January 25, 2018, 11:09:41 PM »
I did not know that, Jon. You are absolutely right. A Coulter would be the worst choice for that project. I can hardly believe anybody would do that. Glen

swittetsakee

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Re: Optical Quality of Coulter 13.1 Inch Mirrors?
« Reply #16 on: January 30, 2018, 12:20:36 AM »
unless you refigure it before cutting it up. sometimes its a cheap way of getting a nice mirror. all the grinding and polishing are done just fix the figure. and since a lot were only figured to 1/2~...strip the coatings and finish the figure.

I'd stick with a full 13" mirror.

on Vlad's site he states that the off axis segment [either cut out or masked off] reduces the wavefront error by a factor of 4. so if the parent mirror starts out as a 1/2~....

coachroninil

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Re: Optical Quality of Coulter 13.1 Inch Mirrors?
« Reply #17 on: January 31, 2018, 12:23:37 PM »
The optical quality of my 13.1 Coulter was poor. So was the mechanical quality. I sold the telescope and decided to spend more to get better quality.