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Description: | Airy's Transit Circle. There are parts marked AST0991.1-66 which can be found via the Whole/Part toggle. Object glass 8.1 inches aperture, 11 feet 7 inches focal length, magnification 195 (180 for the Sun). Eye-end: originally 7 vertical fixed wires & 1 horizontal wire movable by micrometer; 6 additional vertical wires added in 1854 with introduction of chronograph to give 9 wires for galvanic registration & 7 for 'eye-and-ear': in 1891 a 10-wire galvanic system was introduced to simplify arithmetic: travelling wire micrometer fitted in 1915. Bohenberger nadir eyepiece for ascertaining level errors. Handle by window replaced by conservation department.
Inscription. Parts in FH717 11C
caption: Record Shot - Do not reproduce. | Publisher: | "http://collections.rmg.co.uk/" | Rights holder: | "Royal Museums Greenwich" | Source: | Royal Museums Greenwich | Identifier: | http://collections.rmg.co.uk/collections... | Go to resource |
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