Australia’s first observatory was built on the shores of Sydney Harbour by Lieutenant William Dawes of the First Fleet, on the point where the southern pylon of the Sydney Harbour Bridge now stands. Optical astronomy was essential for maritime navigation, and for providing precise location measurements for surveying the new continent.

The country’s first major observatory was established in 1821 at Parramatta by Thomas Brisbane, Governor of New South Wales and, later, President of the Royal Society. The observatory was used to discover and record the galaxy NGC 5128—a now much-studied galaxy that radio astronomers know as Centaurus A, within which sits a super-massive black hole (see Recording the impact of a super-massive black hole).

Great Southern Sky

Sydney Observatory took over from Parramatta in the late 1850s. Its main purpose was timekeeping, but it was heavily involved in studying the southern sky. Meanwhile, following the Victorian gold rush in the 1850s, booming Melbourne opened its own observatory in 1863. The Great Melbourne Telescope at Melbourne Observatory was, for a while, the largest fully steerable telescope in the world.

In the 1890s, the Sydney, Melbourne and Perth observatories began mapping the southern skies as part of the international Astrographic Catalogue (Carte du Ciel) project, perhaps one of the first multinational scientific endeavours. The final parts of the vast Catalogue were completed at Sydney Observatory in 1971.

In 1924, the Federal Government established the Commonwealth Solar Observatory at Mount Stromlo outside Canberra, concentrating on solar and atmospheric investigations. During the Second World War it was pressed into service for the production of ‘optical munitions’, such as gun sights. Post-war, the focus shifted to stellar astronomy in general, and in 1957 it joined the Australian National University (ANU) as the Mount Stromlo Observatory. The Observatory was badly damaged by bushfire in 2003, but has since been revitalised with new facilities for building instruments for its own and other telescopes (see Mount Stromlo Observatory rising from the ashes).

Although observations were made from Stromlo up until 2003, by the 1960s light pollution from Canberra had become so bad that the ANU decided to establish an observatory at Siding Spring Mountain, near Coonabarabran in northern New South Wales. Since that time, the ANU has opened Siding Spring Observatory to a wide variety of telescopes operated by external groups. Today, a dozen external facilities are operating or planned there, including telescopes operated remotely by researchers in countries such as Poland, Korea, Chile, the US and the UK.

Optical excellence

In 1973, Britain built the UK Schmidt Telescope at Siding Spring, a 1.2-metre telescope specially designed for taking wide-field survey photographs. The Schmidt made several photographic surveys of the whole southern sky, creating an archive that has been hugely valuable to professional astronomers and has now been incorporated into public tools such as Google Sky and Microsoft’s Worldwide Telescope. That imaging survey role has now passed to the ANU’s new automated telescope at Siding Spring, SkyMapper, which is embarking on the first complete digital survey of the southern sky (see next page). However, the UK Schmidt—now an Australian-run facility—continues to operate, carrying out large-scale spectroscopic surveys, capturing and analysing the light from 150 stars or galaxies at once. One such survey is the international RAdial Velocity Experiment (RAVE), which seeks to trace how our galaxy developed (see Profiling and fingerprinting the stars).

In 1974, just a year after the UK Schmidt Telescope began operating, a new, large optical telescope opened its doors at Siding Spring: the Anglo-Australian Telescope, a joint UK-Australian project. At the time it was one of the largest telescopes in the world, and one of the first large telescopes to be controlled by computer. Today the AAT is no longer one of the world’s largest telescopes, but it is still one of the best. It is the top-ranked 4-metre-class telescope in the world (with more than twice the number of citations than the second-placed). In fact, among all telescopes—including the Hubble Space Telescope and ground-based telescopes twice its size—the AAT is ranked fifth in productivity and impact. It became a wholly Australian facility in July 2010.

Extremely large telescopes

The new cutting-edge for optical astronomy is the current generation of 8-metre-class telescopes, and the coming generation of ‘extremely large telescopes’. Australia does not have a suitable mountain-top site for such facilities, so Australian institutions, supported by the Australian Government, are collaborating in projects offshore.

One of those projects is Gemini, the world’s largest publicly funded optical/infrared telescopes. The twin telescopes, located in Chile and Hawai’i, can collectively access the whole night sky. Australia has also joined the Giant Magellan Telescope project, to build one of the next generation of extremely large telescopes, an instrument capable of producing images ten times sharper than the Hubble Space Telescope.

PHOTO: SIDING SPRING MOUNTAIN’ IS HOME TO OVER A DOZEN AUSTRALIAN AND INTERNATIONAL TELESCOPES. CREDIT: FRED KAMPHUES.

National Committee for Astronomy, Australian Academy of Science, Canberra
Professor Elaine Sadler, Tel: +61 (2) 9351 2622, ems@physics.usyd.edu.au