Sydney Observatory and the Carte Du Ciel or Mapping the Stars Project

In Autumn 1886, George Gabriel Stokes, President of the Royal Society of London received a letter from Admiral Mouchez, the Director of the Paris Observatory, "… in response to the presentation of specimens of the admirable star photographs by the MM. Henry, several astronomers to whom they had been sent suggested that it would be well that a conference of astronomers of various nations should be held, with a view to taking concerted action for obtaining on a uniform plan a complete map of the whole starry heavens."



Stokes agreed to the proposal, on behalf of the Royal Society, and the conference was eventually held in Paris in 1887. At the top of the agenda items was Mouchez's proposal which became known as the 'Carte du Ciel' or 'Mapping the Stars' project. Although little known today it was worked on by 18 observatories around the world and heralded the start of one of the most ambitious photographic projects the world has ever seen. Eventually the project became known as the Carte du Ciel or 'Great Star Map'.

H. C. Russell was present at the conference and he agreed, on behalf of Sydney Observatory, to take part in the project. What he could not have guessed, was that Sydney Observatory would still be working on it, 70 years later. H. H. Turner, who developed specialised photographic plate measuring instruments for the project, estimated the project required 22,154 photographic plates, weighing in at around three tons. In addition instruments and lenses all needed to be constructed to the same specifications. These once installed in Observatories around the globe would eventually require countless hours in exposing and measuring of the photographic plates. 

At the close of the 1887 conference the eighteen observatory's involved in the project returned home and set about ordering their equipment and resources for the project. Melbourne and Adelaide Observatory's ordered complete astrographs from Sir Howard Grubb of Dublin, but Sydney requested only the lens. 

H. C. Russell, at Sydney Observatory, oversaw the local manufacture of the casing and mount for the refracting telescope which would house the Grubb lens. This work was divided between two local Sydney firms, Mort's Dock and Engineering Co. and the Atlas Engineering Co. The clockwork microscopes, all the smaller parts and the putting together of the instrument were all done by Mr. W. I. Masters, the instrument maker at The Sydney Observatory. Completed in 1890 this was a very ambitious engineering project for the colony and, in the end, only the Grubb lens and a Troughton and Simms tangent screw wheel, marked with very fine graduations, were made overseas. 

While Russell undoubtedly benefited from experimenting with the Grubb lens his resulting photographs were not able to be used for the ''Mapping the Stars'' project. This was because the lines of measurement on the photographic plates were created with an untested reseau, sent to him by Admiral Mouchez, the Director of the Paris Observatory. 

In time the tested reseaux arrived enabling the 'Star Camera' to be used over many years on the ''Mapping the Stars'' project. In addition it was used by James Short and H C Russell to photograph the moon and other stellar phenomenon. The camera operator for almost all of the photographs produced using the 'Star Camera' was James Walter Short, who was appointed in July 1890 and retired in 1930 after spending much of the intervening forty years taking photographs of stars for this project.

Geoff Barker

References
Nangle, J., 'The Sydney Observatory; its history and work, Sydney Technical College, 1930
Russell, H.C., 'Preparations Now Being Made in Sydney Observatory for the Photographic Chart of the Heavens', in Journal and Proceedings of the Royal Society of New South Wales for 1891, Kegan Paul, Tench, Turner & Co., Limited, London, 1892
Russell, H.C., 'Notes on Some Celestial Photographs recently taken at the Sydney Observatory', in Journal and Proceedings of the Royal Society of New South Wales for 1891, Kegan Paul, Tench, Turner & Co., Limited, London, 1892
Russell, H.C., Description of the Star Camera at The Sydney Observatory, Alfred James Kent, Government Printer, 1923
Todd, David, P., Stars and Telescopes, Sampson Low, Marston, and Co., 1900
Turner, H. H., The Great Star Map, John Murray, London, 1912
Wood, Harley , Sydney Observatory 1858 to 1958, Sydney Observatory Papers
Wood, Harley, Astrographic Catalogue 1900.0, Sydney Section -52° to -64°, from Photographs Taken at the Sydney Observatory, New South Wales Australia, volume LIII, V.C.N. Blight, GovernmentPrinter, 1971