Telescopes - Siding Spring Observatory
The 40-inch Telescope
The 40-inch Telescope was the first telescope constructed at Siding Spring Observatory and was designed for photography or photoelectric work.
In addition to housing the telescope, the building also included accommodation and a library.
The telescope took its first images on 12 February 1964, and over its lifetime it was used for important research including Bart and Priscilla Bok's research into the structure of the Milky Way and Magellanic Clouds. Director Olin Eggen also dedicated one week each month to research using the 40-Inch Telescope.
In later years, CCD imagers and spectrographs were built for the telescope and used to extend its capabilities. The Wide Field Imager (WFI), a camera that boasted a mosaic of 8 CCDs, each with 4000 x 2000 pixels, was used extensively from 1999.
Research programs undertaken using the 40-inch Telescope have included those in areas of observational cosmology, the dynamics and evolution of galaxies, the structure and evolution of the Milky Way and Magellanic Clouds, stellar astrophysics, and the search for extra-solar planets.
The 16-inch Telescope
The 16-inch Telescope, purchased from Boller & Chivens, was the next telescope in operation at Siding Spring Observatory after the 40-inch Telescope c. mid-1960s.
In addition to housing the telescope, the building included mechanical and electronic workshops.
The telescope was designed as a photometric telescope to follow up observations made using the 40-inch Telescope, and it proved useful for the provision of zero point standards between 8 and 12 magnitude and for working on brighter variable stars. It also had a 20cm Schmidt camera mounted on it for photographic studies of very large nebulae.
The 24-inch Telescope
The 24-inch Telescope was the third telescope installed at Siding Spring Observatory. Like the 40-inch and 16-inch Telescopes, it was supplied by Boller & Chivens. It was built on site and was commissioned in 1966 under the directorship of Olin Eggen.
In addition to housing the telescope, the building also contains an aluminising plant room to enable the recoating of mirrors up to 40 inches, as well as storage areas.
The 24-inch Telescope is an f/18 Cassegrain on an equatorial mount. Astronomers Don Mathewson and Krzysztof Serkowski began taking polarimetric observations with the double channel polarimeter on the telescope in November 1966. Mathewson went on to use this telescope to compete a two year observation of 2000 stars and collect the most accurate and polarization measures ever obtained. From this he constructed the first consistent magnetic field chart of our local arm of the Milky Way.
In its later years the telescope was primarily fitted with instruments for photometry and imaging work, and used mainly for photoelectric photometry. The telescope has now been decommissioned and the building is now used as the International Telescope Operations office.
The Anglo-Australian (3.9m) Telescope
The stand-out telescope at Siding Spring Observatory was the 3.9m telescope, known as the Anglo-Australian Telescope. This was a joint venture of the Australian and British Governments, announced in 1965. Debates, arguments and delays meant it was not until 1974 that it officially opened by H.R.H. Prince Charles, Prince of Wales, and it was June 1975 before it was in regular use, several years after Bart Bok and wife Priscilla had left Stromlo to move to the University of Arizona.
In 1993, Director Matthew Colless and Richard Ellis led the 2dF Galaxy Redshift Survey, using the Anglo-Australian Telescope to study “both cosmology and the galaxy population with a precision and with a sample vastly superior to anything that had been done before” (Bhathal, Sutherland & Butcher, 2014). This research was highly significant in estimating dark matter.
The AAT is an equatorially mounted telescope and, with a 3.9m-diameter mirror, is the largest optical telescope in Australia. It is equipped with a robotic spectrograph that can simultaneously observe hundreds of galaxies and stars. It has been used to carry out several important southern sky surveys, and plays an important role in the search for planets around other stars.
The Advanced Technology Telescope (2.3 metre Telescope)
In the early 1980s a new telescope was designed for Siding Spring Observatory, known as the Advanced Technology Telescope (ATT) or 2.3m Telescope. The project was driven by Director Don Matthewson and resulted in a telescope that introduced several new technological innovations that had not been combined in a single instrument previously – an uncommonly thin mirror, an alt-az mount, and a rotating building (ANU Research School of Astronomy and Astrophysics, n.d.).
Work on this groundbreaking new telescope was undertaken entirely by the teams at Mount Stromlo and Siding Spring Observatories and its design has been a prototype for advances in telescope design and engineering.
The 2.3m Telescope is currently used by students from ANU and other universities and provides hands-on experience of observing with a large optical astronomical telescope.
