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Numéro d'artefact
2002.0291.017
contexte Fonction
USED TO MEASURE LATITUDE, AND FOR TIME DETERMINATION.
contexte technique
PZT IS VERTICALLY MOUNTED TELESCOPE USING POOL OF MERCURY AT BOTTOM TO ENSURE THE LINE OF SIGHT IS EXACTLY TO/AT THE ZENITH. CONCEIVED BY SIR GEORGE AIRY IN 1854, THE 1ST PZT WAS BUILT C.1909 BY FRANK ROSS. IN 1911 IT WAS PLACED IN OPERATION IN MARYLAND FOR USE BY THE US COAST & GEODETIC SURVEY. BY 1960, 9 OTHERS WERE BUILT & INSTALLED IN OBSERVATORIES AROUND THE WORLD. (REF. 1)
contexte Canada
2ND, LATER PHOTOGRAPHIC ZENITH TELESCOPE (PZT) BUILT AT US NAVAL OBSERVATORY C. 1967-8, AND USED AT DOMINION OBS. IN OTTAWA UNTIL EARLY 1990S. IT REPLACED ORIGINAL PZT BUILT IN 1951 BY DOMINION OBSERVATORY SHOPS (PRECISION COMPONENTS); VICKERS LTD., MONTREAL (CASTINGS); AND PERKIN ELMER CO., GLENBROOK, CT (OBJECTIVE). ( REF.1)
Description
METAL; SYNTHETIC
Nombres de pièces
42
Fini(s) de l'artefact
Goldtone and silver metal casing; bright yellow windings; black synthetic covering on electrical cords. Central post is not secured within solenoid; marked .17 PT.
Marques sur l'artefact
Logo- "G" within shield- stamped into one end of casing. "0099" (?) stamped in black ink on one long side of casing. "GUARDIAN [logo] ELECTRIC/ 4 DC- 1- 24 V DC" stamped in black ink on one side of windings coil.
Groupe 1
Astronomie
Catégorie 1
Équipement d'observation
Sous-catégorie 1
Télescopes optiques
Matériau(x)
métal;synthétique