"surprising how much oversampling you really need"
The Nyquist criterion for sampling a Gaussian PSF is FWHM = 3.3 pixels. So?"3.3 times oversampling" may actually be proper sampling for the best frames.
The PSF?of very short exps?is not Gaussian?but rather a?variably convolved Airy disk/ring function, for which?the Nyquist criterion for?Gaussian PSF is not fully adequate.? Additionally, stacking introduces alignment issues that potentially degrade?sampling and thus benefit from "oversampling".
Stan
