The Saga of the Astrographic Telescope at Sydney Observatory

1986 the dome being lifted off the building revealing the astrographic telescope. Photo Nick Lomb.

In 1986, the Astrographic Telescope, together with the dome covering it, was moved from Sydney Observatory to Macquarie University. Its last use was to photograph Halley’s Comet that returned in that same year. The telescope had been the Observatory’s main research instrument but became superfluous when the Observatory came under the auspices of the Powerhouse and research ceased in 1983.

The photographs above were taken by Nick Lomb and show (left to right) the dome being lifted; the telescope being removed by crane; the demolition of the building.

The telescope has two tubes. One has a 13-inch (33-cm) lens and functions as a giant camera, while the other is a guide telescope with a 10-inch (25-cm) lens. The guide telescope was needed as the accuracy with which the mount tracked the apparent motion of the sky was not perfect and sometimes it moved a little fast and sometimes a little slowly. The astronomer looked through crosshairs at a star and if it drifted off, speeded up or slowed down the telescope, as needed. One of the authors (NL)  can attest that this was not easy to do at 3 am in the morning! If he or she drifted off to sleep during an exposure, the star images on the resulting photographic plate were streaks instead of round dots.

The telescope was built by the Dublin telescope maker Sir Howard Grubb. They were built specifically for the Astrographic Catalogue project that originated at a conference in Paris in 1887. This conference decided to use the then new technique of photography to compile a catalogue of star positions over the entire sky. The sky was divided into zones with the zones allocated to various observatories. The NSW Government Astronomer, Henry Chamberlain Russell, accepted a large zone of the southern sky and another large section on behalf of Melbourne Observatory.

Unlike other observatories, Sydney Observatory did not buy an entire telescope for the purpose. Instead, it just purchased the lens and Russell had the tube and mount built locally. This telescope had an English mount, with the telescope inside a fork that allowed it to move up and down, that is, in declination. The fork was aligned north-south and attached to two piers and could rotate east or west, that is, in right ascension. This was similar to the French designed astrographs.

This initial astrographic telescope was replaced with the Grubb telescope from Melbourne Observatory when that observatory closed down in 1944. At Sydney, the telescope was placed in brick housing capped by a rotating dome. As mentioned, in 1986, both the telescope and its dome went to Macquarie University.

The dome was removed to Macquarie University by trailer across the Harbour Bridge

Unfortunately, the planned public observatory and planetarium there did not eventuate, due to lack of funds. However, both the instrument and dome were preserved there for about three decades.

The completed East Dome building showing the restored dome on top of a new building and the Astrographic telescope is in the adjacent connected building on the right. Photograph by Nick Lomb.

Recently, the telescope and its dome came back to Sydney Observatory and housed in a new building topped by the dome at its original location. The building named 'East Dome' was opened on 27 January 2015. The Department of Ageing, Disability and Home Care NSW sponsored the construction of the building, in particular the internal lift that takes people up into the dome, and the purchase of a new accessible telescope fitted with an articulated relay eyepiece. Now people with reduced mobility are able to have an equitable telescope dome experience.  

NSW Public Works supported the project by restoring the dome and the Powerhouse conservators and volunteers restored the Astrographic Telescope that is part of the static display next to the dome. The building, designed by the NSW Government architects Angus Donald, Vivian Soutas and Terry King, won the prestigious 2015 National Trust Award for adaptive re-use.

The Authors

Adjunct Professor Nick Lomb is the Chair of the History of Australian Astronomy Chapter of the ASA. He was the curator of Sydney Observatory in addition to astronomy, horology, surveying and meteorology for the Powerhouse Museum until 2012.

Dr Toner Stevenson is the Secretary of HAAC and was the Manager of Sydney Observatory during the construction of the East Dome when she led the steering group for the project.