I'm pretty sure it's the low temp of the glass that aids the vaporized Al to coat the mirror. I don't think the mirror is heated. I may be corrected here. We used to use the same process to put the al onto polycarbonate discs to make CD's.
Quote:
Originally Posted by wasyoungonce
1st stupid question for this .....doesn't the main mirror need to be removed form it's carrier to re-coat?
I thought the mirror was placed in a vacuum chamber & baked at temp then the pre-heated to high temperature aluminium was introduced into the chamber thru a 2econdary slot that kept the vacuum intact.
Then the lot was allowed to cool, slowly.
I believe most SCT main mirrors are glued to their carriers with a 2 part epoxy goop that will melt in at temps exceeding around 150°C .
Maybe I'm talking thru my hat  ...anyone else shed advice on this?
If you can get a re-coat for $300-$500...then it's a bargain scope indeed. |