An investigation of star/galaxy separation from matched direct and objective-prism plate samples

Abstract

The authors report on a novel investigation of star/galaxy separation using matched samples from direct and low dispersion objective-prism plates taken with the UK Schmidt telescope (UKST). The plates were measured with the COSMOS machine. The extra information provided by the image match between the two types of plate gives a powerful means of discriminating between stars and galaxies. The results highlight the difficulty of classifying the two types of image using direct plate data only stressing the need for a careful and objective approach to the problem.