Quote:
Originally Posted by h0ughy
i am with you on this Dennis, i think this method looks far better then the Hartman mask with diffraction gratings. I downloaded the files off cloudy nights but do not have Corel draw. might have a go at a CAD drawing of this and send it to a CAD/Cam cutter to make it up for the 8" vixen, the 127ED and the 8" SCT and the ED80, oh and the 10" lx200R.
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Hi Dave
So far, I have found that the Bahtinov Mask works at the prime focus of the Mewlon and also with a TeleVue x2.5 PowerMate in the optical train, both visually and with a DMK21AF04.AS as the sensor.
So, even though the calculation as written, of Focal Length/(
Range 150-200) = Bar + Space dimension gave me a Bar Width of 6mm and a corresponding Bar Gap of 6mm using a fl of 2160mm, the same mask seems to hold up even at a fl of 5400mm.
At shorter focal lengths of say, 800mm and less, the formula changes to 3xF/(
Range 150-200) so the bars don’t get too thin.
Therefore, for your larger ‘scopes, you may only require the largest mask with some means of fitting it to the smaller scopes, rather than a mask for each?
Cheers
Dennis
PS – I drew up my mask in Corel Draw and would be happy to send you a high res file if you want it.