Another Ebay adventure: I impulsively made a “best offer” on ebay over the Thanksgiving Day weekend and wound up with a 16″ blank … to be sure, at a bargain basement price, but – gulp – is this really something I need? Well, no … not need; but you never do know when it’ll be useful ;>) . We’ll just have to store it in the basement for a rainy day and’ll see what happens without, in the meantime, compromising the 12.5″ project.
This mirror is 16″ in diameter and 3.125″ think. A ground face has a sagita of ca .85″ and thus a focal length of 188″ and a focal ratio f/11.8. The ground surface is coated. The coating has a yellow/gold tint.
There are a few chips on the circumference of the ground face of the blank. The back face of the mirror is unblemished and relatively flat. There is an odd imperfection in the pyrex, but not one that would be ground into.