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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

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    Plastic lenses

    Swarodur and Meoshield for example. AFAIK the highest Abbe no. among plastic lenses is 59 for CR-39. That is about equivalent to BK-7, the old established crown glass. Most othe plastic materials are in the region of flint glass, so colour correction in binoculars or photographic lenses...