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same as Suavi - SGP, 9 point with 2x2 binning and restrict the size of the focus field for broadband (who needs 700 stars?). at f4 expose for 4 sec broadband and 10s through NB filters (may need to use full field for NB - not many stars). focus is real quick, so redo every 12 minutes (generally works OK, but may decide to use shorter updates if focus is likely to be drifting in rapidly varying temps)
use fairly small steps to get a u curve around focus, rather than a sharp v - seems to work best and the symmetry of the curve is a good visual check on collimation (which needs occasional tweaking).
Astronomik filters seem to be true parfocal - no offsets needed on this system.
Last edited by Shiraz; 26-02-2017 at 10:11 AM.
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