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RE: RE: I Need Help Identifying Glass!

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Posted by Steve Henderson on August 4, 2000 03:22:50 UTC

The lens design is a cooke triplet. Made by Projection Optics, with a plano convex, double concave, double convex with unequal curves.

My preliminary results are:

The plano convex has an index of about n=1.61 which is likely to be BAF4.

The double convex has an indes of about n=1.58 which is likely to be BALF4 or LF5.

The flint double concave is about n=1.65 which might be SF2.

I determined these by measuring the curves with a spherometer, and measuring the back focus using a red light source at a measured distance. I plugged the info into the OSLO LT program and checked which common glass types fit best.

I`ll keep you posted when I get better info.

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