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

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  1. T

    How can 60mm be better than 80mm (help needed)?

    Thanks again. I was sort of hoping that a good birding scope would get very close. I once put up my ATM65 HD against a TV60 using a 3,5 mm Nagler and had the impression that the Swaro didn't give anything away. However, magnifications differed due to the focal lengths (460 and 360 mm). John
  2. T

    How can 60mm be better than 80mm (help needed)?

    Thanks, Joachim, but I was thinking more in terms of astro vs. birding, i.e. the ED80 vs. your TSN. John
  3. T

    How can 60mm be better than 80mm (help needed)?

    I read recently that US and British military use a 12-40x60 Leupold scope for a certain application. Would have thought that if they needed a milrad reticle, a Swarovski STR-80 weould have been the better choice. Surely not a case of 60 mm being better than 80 mm? Regards, John
  4. T

    How can 60mm be better than 80mm (help needed)?

    A big reflector or big achromat will certainly allow more magnification than a good spotter but terrestrially the reflector will lack contrast and the achromat will show false colour. There was a thread on CN recently, asserting that smaller faster apochromats could outperform long achromats...
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