Today marks the 50th anniversary of the opening of the Anglo-Australian Telescope (AAT) by by the then Prince of Wales, now King Charles. The 3.9m telescope’s excellent optics, exceptional mechanical stability and precision computer-control make it one of the finest telescopes in the world. Not surprisingly, when the Siding Spring Observatory held its Open Day earlier this month as part of annual StarFest weekend the AAT was the main attraction. The day also featured presentations by internationally-acclaimed astronomers, science displays, food stalls, solar observing, AAO and Macquarie Uni information stalls, Rural Fire Service displays, and the Coonabarabran Town Choir singing in the AAT Dome! The image above shows the choir, dressed in black, at top right (on top of the telescope control room). (Image credit: Marilena Salvo)