Okay, sighting on downtown lights, I get 89 inches from the back of the cell to the base of the RKE 28mm the stop where it goes in the focuser).
THe cell is 2.5" wide, so if the objective is considered in the middle of that, then I get 91.25" focal length, or f/15.2. If f is measured from the rear of the achromat, then the FL is 89", or f/14.8.
Safe to assume f/15 and build accordingly?
-Tim.
-------------------- "We`re just waiting looking skyward as the days come down.
Someone promised there`d be answers, if we stayed around."
-Orchestral Maneuvers in the Dark, "The Romance of the Telescope"
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Re: 6" f/15 Jaegers - OTAing this weekend!
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