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Old 02-02-2010, 02:34 PM
malmac (Mal)
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malmac is offline
 
Join Date: Nov 2009
Location: Geraldton
Posts: 1
Quote:
Originally Posted by Bern View Post
Hello everyone, this is my first post, and I am impressed by the amount of information and knowledge available here. Do people still hand grind their own mirrors, or is this a dying art? My late father made several telescopes in the 1960s and '70s, mainly Newtonians and a casegrain. The primary mirrors varied in size from 4.5 inches to 8 inches. In the final stages of polishing he would assess the accuracy of the optics and focal length using various methods, such as straight-edge and grid tests, I think. He used different hand-polishing manoeuvres to correct optical deficiencies. I recall him referring to turned-down edges and turned-up edges among other things. He never had much time for commercially made or machine-ground mirrors because he felt they weren't up to standard or were just too expensive because of the enormous amount of labour required to make them. So how does the optical quality of current commercially made mirrors compare with hand-made ones? I would imagine mirror manufacturing technology has improved vastly since my father's time, but is a good hand-grind-polish job still regarded as superior to a commercial job? If not, how do you independently assess optical flaws in a commercial mirror before purchasing it? Also is there much optical variation within identical telescope models? Thanks for taking the time to read the post.

Bern
This is my first post. I have started to grind my first mirror (8 inch F 7 to 8). This will be a prolonged project as I am about to relocate from Dongara W.A. to Geraldton W.A. and have packed everything away for the move.
I am keen to hear the opinions of others regarding "bought" vs "handmade" mirrors. My understanding is that few people in Australia grind mirrors now. It is still popular in America and Europe though.

I will look at any responses with interest.

Cheers for now...............Mal
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