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Carte du Ciel

CDC-Archives

The collection contains prints produced from photographs taken with telescopes of various sections of the sky, and from different observatories throughout the world, as part of the 1887-1964 Carte du Ciel celestial mapping project. The prints, some produced on plain paper and some on photographic paper, date between 1892 and 1933.\n \n All the prints show a square section of the sky, on which a grid is overlaid. Each print is centered on a line of declination horizontally, and on a line of right ascension vertically. These coordinates are recorded in the headings or captions included on each print. The coordinate scale of the grid sometimes differs between observatories, but most range from -65 to +65 arcsecs/mm on both the x and y axes.\n \n Each print is a composite of three images of the same section of sky, taken from slightly different angles and overlaid on each other. The exposure time for each image was generally 20 minutes. This technique was used to help identify flaws in the photographic plates, and to identify objects that passed briefly through the sections of sky during the exposures, such as asteroids. As a result of the overlay, the stars can be seen to have three "points."\n \n The collection does not represent the complete collection of celestial mapping prints from all participating observatories in the Carte du Ciel project.

Approximately 20 linear feet of astrographic charts or photographic prints of such charts. Approximately 3,750 charts total.

Celestial charts, Carte du ciel, Observatoire de Bordeaux (France), Observatoire de Paris, Observatoire de Toulouse, Observatoire d’Alger, Observatoire royal de Belgique, Observatorio de San Fernando, Royal Observatory, Greenwich, Specola vaticana

cartographic material

COLLECTION