pixel scale: under sampling, image appears jagged or blocky 2.393 arcsec / pixel: original photo here over sampling 0.131 arcsec / pixel: original photo here The original photo is downsized to 12.5% for easier comparison. Stars are supposed to be bloated, but this is not obvious. same image, without downsizing but cropped: The stars surely are spiky, but are they bloated or not? As nowadays, stacking or lucky imaging(low arcsec per pixel), together with powerful post-processing techniques, over-sampling seems to be less of an issue IMHO, good focus and tracking, long cumulative exposures, high signal to noise ratio, good post processing is more important for 0.3 arsec / pixel scale, usually it is use with large aperture (> 1m) telescope in observatory skyandtelescope telescopes available to UK astronomers