Quote:
Originally Posted by Peter Ward
Sorry, that's not quite right, 2 arc sec per pixel would result in tragic planetary images hence high res-planetary imagers use FL's that sample the sky well beyond Nyquist .
All I'm saying is you simply can't divorce the seeing that easily from the equation. Oversampling through longer FL's can and does give tighter stars and also helps with deconvolution.
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Well Peter, if you can take deep sky shots at 60fps then knock yourself out. It is only that and the stacking of hundreds of exposures that freezes out the seeing. As long as the image is adequately sampled, longer focal length on influences image scale. Some level of oversampling is required for deconvolution (particularly Maximum Entropy based algorithms) to work properly. As soon as the exposures ar more than a second or so you are at the mercy of seeing and Nyquist holds quite well. Like I said there is a good series of articles from Craig Stark at CloudyNights, read them for a proper explanation.
Cheers
Stuart