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Numéro d'artefact
2002.0291.004
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, GLASS, AND SYNTHETIC MATERIALS OF CONSTRUCTION; .4PT ACCESS PANEL COVER: WOOD PANEL; LEATHER COVERING; BRASS KNOB; .4PT WEIGHT: LEAD
Nombres de pièces
42
Fini(s) de l'artefact
MOST COMPONENTS ARE SILVER (NATURAL METAL OR PAINTED FINISHES); HINGED LENS COVER & PROTECTIVE CASING ENCLOSING ELECTRICAL WIRES PAINTED BLACK. BLACK PADDED RINGS ON BASE./ .4 PT access panel cover: Wood panel covered in black pebble-textured leather; brass knob fitted to top./ .4 PT weight: Presumably lead; designed to be suspended from metal hook secured to monofilament line.
Groupe 1
Astronomie
Catégorie 1
Équipement d'observation
Sous-catégorie 1
Télescopes optiques
Matériau(x)
métal;verre;synthétique