... There will likely be science programs that do not fit exactly into any one of these categories, or that have different requirements. Very Short Exposures : If each target is observed for less than a few minutes then the extra overhead for dithering can significantly impact the overall S/N, thus offsetting any advantages gained by dithering . ... Even if sub-pixel dithering is not necessarily required, dithering each exposure by an integer pixel shift reduces the impact of hot pixels. ...