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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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Negative - View of Melbourne Observatory, 1929
View of Melbourne Observatory, taken from the 50 foot anemometer tower, looking south and southwest. Anemometer erected 1906.
From: South Yarra, Australia Images: 1 -
Negative - Main Building, Melbourne Observatory, post 1883
View of northern elevation of main building at Melbourne Observatory (post 1883, when East Transit Room was erected), and prior to erection of Computing Room in 1892.
From: South Yarra, Australia Images: 1 -
Negative - South Equatorial House & Photoheliograph House, Melbourne Observatory, 1969
View of South Equatorial House and Photoheliograph House, Melbourne Observatory.
From: South Yarra, Australia Images: 1 -
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Glass Negative - Main Building, Melbourne Observatory
View of Main Building, Melbourne Observatory, and gardens leading to entrance. Photo taken post 1902, after the erection of the Astrophotographic Room, visible on the right.
From: South Yarra, Australia Images: 0 -
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Telescope & Striding Level - Theodolite, Troughton & Simms, 10 Inch
Telescope and striding level of 10 inch theodolite made by Troughton & Simms, London. Used at Melbourne Observatory.
From: London, United Kingdom Images: 0 -
Negative - Erection of Great Melbourne Telescope, 1869
Erection of the Great Melbourne Telescope at Melbourne Observatory, 1869.
From: South Yarra, Australia Images: 2 -
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Stand & Horizontal Circle - Theodolite, Troughton & Simms, 10 Inch
Stand and horizontal circle of 10 inch theodolite made by Troughton & Simms, London. Used at Melbourne Observatory.
From: London, United Kingdom Images: 0 -
Electron Tubes
Geissler tubes, which show various effects of the passage of electricity through rarified air, gases, etc. The tubes have platinum or aluminium terminals. 6 examples with different shap ...
From: South Yarra, Australia Images: 1 -
Negative - Equatorial Telescope, 8 Inch, Melbourne Observatory
Eight inch equatorial telescope at Melbourne Observatory. Telescope made by Troughton & Simms, London, and installed at the observatory in 1874, in time for Transit of Venus observation ...
From: South Yarra, Australia Images: 1 -
Negative - Jeffree Telescope, Melbourne Observatory, circa 1960
The Jeffree telescope in the Astrograph House at Melbourne Observatory, circa 1960. The Jeffree Telescope was built in the 1930s at the Bendigo Railway Workshops, and purchased by the ...
From: South Yarra, Australia Images: 1
