Quote:
Originally Posted by bratislav
Harrie Rutten told me that he is aware of several Companars successfully built, the largest one being 12 inches. It was also commercially offered (at least at some stage) by Oldham Optical in UK. I don't know how many of those mentioned by Harrie were amateur creations though.
Bratislav
PS most of that old "landfill" glass was made by Chance Pilkington and on larger pieces it has melt data numbers scribed on the glass
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And as Stefan has intimated with respect to the huff and puff about melt data... it really isn't that important on a two element, zero power corrector (of the same glass). It has very little bearing on over all system performance other than to shift the wavelength at which spherical aberration is at a minima.
It's a bit like agonising over the spherochromatism of a Schmidt plate.... you don't need anything more exotic than white water plate (as long as it is homogeneous) and have a rough idea of the refractive index.
~2c