THE GREAT MELBOURNE TELESCOPE AND OTHER 19TH-CENTURY REFLECTORS

With the help of hitherto unstudied diaries and log-books, a detailed study has been made of operational aspects of the Great Melbourne Tele scope (GMT), and its performance compared with that of the much more s uccessful 8o cm Foucault reflector at Marseilles Observatory. The GMT failed not through any fault of its staff, but because its design mean t it could be used only for making pencil-and-eye sketches of nebulae: photography and spectroscopy were precluded. The speculum mirror was a handicap but not a fatal one; a silver-on-glass mirror would have ma de no essential difference. Despite its faults the telescope significa ntly influenced the design of the 36-inch Crossley (or Common) reflect or, and through that of later, larger reflectors.