>> >>> 1. How much would a 10 - 12 inch blank of these >>> material cost? >> >>I looked at a Sitall blank 16" in diameter, with hole cut for a Cassegrain >>and about 3" thick. Cost would have been about $3,500. Stew, At that price you may order a complete set of 16" Cassegrain optics here in Moscow. Alexander Yascovich, Moscow Russia