The UK director of the International Year of Astronomy is to give a talk on his debates with astrologers about their beliefs.
Glasgow Science Centre-based Steve Owens, a former pupil at Culloden Academy, is returning to the Highlands to give the talk on Friday in Nairn.
Highlands Astronomical Society (HAS) and Moray group Sigma are hosting the event.
Year of astronomy events are running throughout 2009.
HAS said until a few hundred years ago astrology and astronomy were often held in equal regard, with astronomers such as Galileo practising astrology alongside their astronomy and mathematics.
However, the society said that advances in science had led astronomers to regard astrology as a pseudoscience.