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New scope F number question
If you were going to build a 10” newt with a conical primary from R.F.Royce that had specs of say ...
“Wavefront accuracy having an RMS of .032 and a Strehl Ratio of .96 or better at 633 nm for apertures up to 10" at f/5 or larger. Mirrors up to 16" and f/5 or larger have a wavefront accuracy having an RMS of .036 and a Strehl Ratio of .94. Mirrors at f/4.5 and lower ratios have correspondingly lower Strehls due to the difficulty of manufacturing fast aspheres.”
and wanted to get the best possible images of Jupiter, Saturn and Mars by chucking a 1.25” X5 powermate (gain X5-7) or a 2” X2 Big Barlow (gain X2-3) on it with a filter wheel and a spc900nc webcam,
what F number would you choose??
Choices are F4.5, 5, 6 and 8.
Cheers
Stephen
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