Renseignements généraux

Nº de série

VA-490

Nº de partie

1

Nombre total de parties

1

Ou

S/O

Brevets

S/O

Description générale

Metal casings, controls and parts/ Synthetic indicator casings, controls, parts/ Rubber hoses

Dimensions

Remarque : Cette information reflète la taille générale pour l’entreposage et ne représente pas nécessairement les véritables dimensions de l’objet.

Longueur

69,0 cm

Largeur

52,0 cm

Hauteur

168,0 cm

Épaisseur

S/O

Poids

S/O

Diamètre

S/O

Volume

S/O

Lexique

Groupe

Astronomie

Catégorie

Divers

Sous-catégorie

S/O

Fabricant

Ou

Blue M

Pays

United States of America

État/province

Illinois

Ville

Blue Island

Contexte

Pays

Canada

État/province

Ontario

Période

mid 1970s +

Canada

An instrument used at the David Dunlap Observatory at the University of Toronto, one of Canada's most important astronomical observatories.The David Dunlap Observatory opened in 1935 as the result of a bequest from the wife of David Dunlap. The telescope was a 74 inch (188 cm) reflector built by Grubb Parsons of Newcastle-upon-Tyne in England. The 74 inch was then the largest telescope in Canada (surpassing the 72 inch telescope of the Dominion Astrophysical Observatory in Victoria) and became the second largest in the world after the 100 inch Hooker Telescope of the Mt. Wilson Observatory outside Los Angeles. DDO's reputation grew and following WWII, it began to graduate most of the astronomers produced in Canada with University of Western Ontario far behind. Beginning in the 1960s a number of other astronomy departments were created but UofT/DDO held its place, a position it probably still holds. The DDO had a good technical staff which gave them an advantage and, with most of the 1940s to early 1970s top astronomers coming from UofT, grants from NRC and then ENSERC were almost guaranteed and allowed UofT's top astronomers -- Hogg, van den Berg, Fernie, Bolton, Kamper, Martin, etc. to acquire or build some of the best equipment available in university observatories. For optical observatories, only the DAO had technical staff and budgets that surpassed those of DDO. In 2007, citing increasing light pollution, the University of Toronto announced plans to sell the Observatory property. In June 2008, it was sold to Corsica Development Inc., a subsidiary of Metrus Development Inc. and the Observatory was closed. In 2009 the Observatory buildings and 80% of the site were designated a cultural heritage landscape. Also in 2009 Corsica and the Royal Astronomical Society of Canada, Toronto Centre announced an agreement allowing the RASC to provide public education and outreach programs at the observatory, and to operate the 188 cm telescope.

Fonction

A piece of equipment used to sensitize photographic plates by baking them in a dark, nitrogen environment.

Technique

A device made circa 1970 to 1975 and used to sensitize photographic plates by baking them in a dark environment for several hours (or longer) in a nitrogen environment. Moisture in photographic emulsions significantly decreased the speed of the plates. Different emulsions reacted differently to the type of gas used to bake the plate as did the temperature and the duration. A limiting factor of astronomical plates was the est. 4 - 7% efficiency, i.e. only 4 to 7 photos falling on the emulsion was actually registered. A related technique was to "pre-flash" a plate with or without baking. This was done immediately before exposure and raised the threshold to register the incoming photons. Baked plates, if tightly sealed, retained their increased sensitivity for a few days or weeks. This piece was assembled by DDO using components made by: Oven: by Canlab mod. Blu-M Contoller: " Power-O-Matic -70 solid state proportioning control" by Blu-M Comp. and controls the oven. Temp range (?) and set at 100 C for use at DDO and second ste at 60 C (range 50-75 C by 2.5 C) Vacuum pump (in base): Welsh Duo-Seal mod. 1400-B80 ser. # 151064

Notes sur la région

Inconnu

Détails

Marques

Plate on casing side reads '[logo] BLUE M BLUE M Electric Company [script]/ BLUE ISLAND, ILLINOIS, U.S.A./ MODEL NO. POM-12VA-2 SERIAL NO. VA-490/ 120V/1PH/60HZ/ MAX. WATTS 100C/ TEMP. RANGE TO 300° C/ 572° F'/ Silver lettering on control panel on right reads ' [logo] BLUE M BLUE M Electric Company [script]/ BLUE ISLAND, ILLINOIS, U.S.A.' and on left 'POWER-O-MATIC-70/ CONTROL SYSTEM COVERED BY US PAT NO. 3392268/ SOLID STATE PROPORTIONING CONTROL'; two indicators labeled in silver 'TEMPERATURE' and 'HEATER VOLTAGE', each with black lettering reading '[logo] BLUE M BLUE M Electric Company [script]/ BLUE ISLAND, ILLINOIS, U.S.A.'/ Silver lettering reads '[logo] BLUE M BLUE M Electric Company [script]/ BLUE ISLAND, ILLINOIS, U.S.A.' on both controls on control panel/ 'Silver lettering for control functions on control panel/ Plates on oven door read '[logo] BLUE M' and 'canlab'

Manque

Unknown

Fini

Grey hammertone painted casing/ Black painted control panel/ Colourless transparent indicator dial casings and white faces on control panel; Black controls; Red lamp/ Brushed metal oven and door and frame, plated handle with black synthetic grip/ Black, red and brown hoses/ Black painted indicator dial with white face mounted on top, with black synthetic handle/ Black painted, gold painted, unfinished metal parts

Décoration

Silver stripe painted around edges of control panel and around edges of circular dial controls