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Positional Astronomy at Melbourne Observatory
Image: Album - Photographs
Source: Museum Victoria
Along with the observations required for timekeeping, positional astronomy occupied the largest part of the Observatory's work. Positional astronomy consisted of the accurate and repeated observations of stars, and then the reduction of the observations to provide a precise location of the star in the sky and its magnitude. When the Melbourne Observatory commenced, this involved the use of the transit telescope and accompanying equipment to fix the location. By the 1880s celestial photography had improved so that it was possible to take series of photos of the sky, then measure the position and magnitude of stars on the photographic plates.
The work of the Melbourne Observatory was of particular importance because it was one of the best equipped observatories in the southern hemisphere, and thus able to observe stars that could not be seen from the European and North American observatories.
In the early years Melbourne Observatory became involved in several international projects. In 1863 Government Astronomer Robert Ellery took observations of the parallax of Mars in conjunction with Greenwich Observatory near London and Pulkowa Observatory in St Petersburg; this was to provide measurements that would aid the calculation of the distance of the Earth from the Sun. The following year, in collaboration with Greenwich Observatory, the Observatory was making observations of the polar distances of stars, to measure the amount of apparent displacement due to the refraction of the Earth's atmosphere. Prior to the Transit of Venus in 1874, the Observatory made large numbers of transit observations of stars that would be used by expeditions from the northern hemisphere observatories to locate the precise position of their field observatories.
Several projects were aimed at measuring as accurately as possible the distances between the planets and the Sun, and therefore understanding the mechanics of the solar system. For example, in 1931 the Observatory used its astrographic telescope to photograph the passage of the minor planet Eros; the photographic plates were sent to Greenwich where astronomer Spencer Jones used them with those from other observatories to more accurately measure solar parallax. His work would not be improved upon until the advent of radio astronomy after the Second World War permitted radar measurements of the distance between Earth and Venus.
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Photograph of comet, probably taken at Melbourne Observatory. Photograph in a photograph album used at Melbourne Observatory, late 19th century. The photographs show the main Melbourne ...
The 8 inch South Equatorial Telescope, Melbourne Observatory. The telescope was built by Troughton & Simms, London and installed in 1874. Photograph in a photograph album used at Melbo ...
Photograph of the Moon at first quarter, taken by Joseph Turner with the Great Melbourne Telescope at Melbourne Observatory around 1874. Photograph in a photograph album used at Melbou ...From: South Yarra, Australia Images: 2
Photograph of the Moon, taken by Joseph Turner with the Great Melbourne Telescope at Melbourne Observatory around 1874. Photograph in a photograph album used at Melbourne Observatory, ...From: South Yarra, Australia Images: 2
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Terrestrial radiation thermometer, made by Negretti & Zambra, London. Range - 10 to +130 degrees Farhenheit. Used at Melbourne Observatory.From: London, United Kingdom Images: 0
Main observatory building, Melbourne Observatory, from northwest. Photo taken between 1883 (after construction of East Transit Room, on left, and 1892, when Computing Room was construct ...
Chronograph for recording exposures on the Astrograph Telescope, Melbourne Observatory. The Astrograph, by Grubb of Dublin, was installed at Melbourne Observatory in 1891. Photograph i ...
Robinson's anemometer, recording equipment. Possibly at Melbourne Observatory. Photograph in a photograph album used at Melbourne Observatory, late 19th century. The photographs show t ...
Altazimuth instrument, probably one used at Melbourne Observatory. Photograph in a photograph album used at Melbourne Observatory, late 19th century. The photographs show the main Melb ...
Chronograph for recording exposures with the Astrograph Telescope at Melbourne Observatory. The Astrograph, by Grubb of Dublin, was installed at Melbourne Observatory in 1891. Photogra ...