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Celestron 11" f/2.2 Rowe-Ackermann Schmidt Astrograph (RASA) optical tube
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10-07-2014, 07:26 AM
RickS
(Rick)
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A back of the envelope calculation shows that increasing back focus from 55mm to 110mm would add about an inch to the diameter of the front corrector lens assembly. I'd say that the 55mm back focus was an economic decision...
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