Quote:
Originally Posted by AG Hybrid
They are 1.8" thick are they not? Must take a while until they are at equilibrium.
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At 1.8" thick crown glass ( 3 X higher coefficient of expansion to Pyrex ) the figure of the mirror is very unlikely to ever reach an equiliberated state. I have had reasonable results with plate up to 1.3" thick. This is essentially one area where there are no free lunches on large low cost scopes.