Quote:
Originally Posted by raymo
Over a number of years back in the 70's I had three Newts I imported from the U.K, 6", 8.5" and 10". All had the primary mirror permanently attached
to the rear cover plate with adhesive. So to inspect or clean the mirror I just had to undo the 3 [6" and 8.5"] or 4 [10"] retaining screws and remove the rear cover complete with mirror. As the cover plate retaining screws were a very snug fit, the only collimation adjustment possible was the secondary mirror. I used these scopes for years for public outreach, and rarely had to make any adjustments. From memory the permanent attachment didn't seem to introduce any aberrations.
raymo
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Thanks Raymo,
at f4 focal ratio the collimation is very critical.
I have had the time to investigate my collimation more closely
and to look for a solution which would allow me
to use the 3 collimation screws normally and to easily adjust it.
I already found that my laser wasn't orthogonal and I fixed that.
The 3 strong anti-lateral movement springs I chose have worked quite well but only
a night out under stars will confirm it -
the bench tests still confirms some small movement -
however I am now looking at
ball joint rods to replace the springs
which would more effectively lock the primary mirror in place
but allow normal collimation adjustment.
https://www.ebay.com.au/itm/165602750441\
I'm not sure how to implement it yet.
see pic
cheers
Allan