The 30-inch Reynolds telescope was the first reflecting telescope on Mount Stromlo and the largest operational telescope in the Southern Hemisphere until the 1950s.
It was donated by British amateur astronomer John H. Reynolds in 1924 and came into operation at the observatory in 1929.
Renowned astronomer and instrumentalist Ben Gascoigne used the Reynolds in the 1950s to study stars in the Magellanic Cloud galaxies, leading to the discovery that the universe was twice the size and age than previously thought.
During the 1990s, the Reynolds was used to monitor supernovae, and contributed to Professor Brian Schmidt's Nobel Prize winning discovery of an accelerating universe.
The telescope was destroyed in the 2003 firestorm, however with the dome remaining intact - the building is now used for research by the ANU Research School of Earth Sciences.