Gregg Thompson was one of the founding members of the Southern Astronomical Society (SAS).
[1] Before 1981 he started making a set of charts of bright galaxies, designed to help deep sky observers in their search for extragalactic supernovae.
[2] In 1985 he received the Amateur Achievement Award of the Astronomical Society of the Pacific, together with Robert Owen Evans,[3] who had made several supernova discoveries using Thompson's charts.
[2] Evans wrote that the number of galaxies he was able to observe grew substantially after the charts were produced.
[6] In 1993 he published The Australian Guide to Stargazing, a manual for both naked-eye and telescope observing of the sky of the southern hemisphere with explanatory diagrams, photographs and detailed drawings, describing the basics of the night sky observation to novice amateur astronomers.