Still extremely slow progress with this project. One reason is that I took on the job of salvaging a brand new 10" astrograph that came with unusable optics and for which the manufacturer failed to take the responsibility of replacing it with a usable one. Well, it turned out to be a much bigger job that I thought it would be and it's been using up much of my spare time. The primary mirror needed complete regrinding/figuring to get rid of major astigmatism, plus a very long list of other mechanical and optical problems that needed fixing.
Anyway, I purchased 3 slices of aluminium alloy 6061, 178 diameter, for the main structural parts, and I cast an Ultracal30 disc for the R2 test plate lap. I prefer alloy 7075 for my projects, for its hardness, but the 6061 alloy also anodizes very well and it is much easier to obtain.
Last edited by Stefan Buda; 18-06-2017 at 06:03 PM.
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