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Old 03-12-2016, 08:19 AM
Stefan Buda
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Stefan Buda is offline
 
Join Date: Jul 2013
Location: Melbourne, VIC
Posts: 841
Quote:
Originally Posted by bratislav View Post
Harrie Rutten told me that he is aware of several Companars successfully built, the largest one being 12 inches. It was also commercially offered (at least at some stage) by Oldham Optical in UK. I don't know how many of those mentioned by Harrie were amateur creations though.

Bratislav

PS most of that old "landfill" glass was made by Chance Pilkington and on larger pieces it has melt data numbers scribed on the glass
Bratislav,
It would be nice to actually see some proof as I don't think that Harrie has actually seen any of those instruments. Why would professional astronomers waste money on such a large and expensive instrument?
Remember that the Companar is huge relative to its focal length. And if those were amateur instruments then we should have seen some results.

Anyway, back to the topic:
In the late 90s I cobbled together a curve generating machine for my 16" Dall-Kirkham project and I've been using it ever since for making all sorts of lenses and mirrors. It is this machine that I used for shaping the glass for the BRH.
Here you can see the shaping of one of the 6" grinding tools.
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