Renseignements généraux

Nº de série

40264

Nº de partie

1

Nombre total de parties

1

Ou

S/O

Brevets

S/O

Description générale

Metal casing, controls and parts/ Synthetic meter casing, controls, carrying strap, feet, parts

Dimensions

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

Longueur

48,5 cm

Largeur

38,5 cm

Hauteur

13,5 cm

Épaisseur

S/O

Poids

S/O

Diamètre

S/O

Volume

S/O

Lexique

Groupe

Communications

Catégorie

Équipement de service et d'essais

Sous-catégorie

S/O

Fabricant

Ou

Keithley

Pays

United States of America

État/province

Ohio

Ville

Cleveland

Contexte

Pays

Canada

État/province

Ontario

Période

mid 1960s +

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

Generally, an instrument for measuring low current, an ammeter with a scale which indicates current in picoamperes. This one was used with the photoelectric photometers of a telescope at an astronomical observatory.

Technique

One of a group of instruments used in the DDO Electronic Shop for calibration and testing of the Observatory's observational instruments. This one was used with photoelectric photometers at the telescope. It has a Keithley Input Head model 4170. Range: 10(-5) to 10-(12) amps (picoamp range). This type of picoammeter is useful for high-speed measurements of low-level currents generated by high-impedance sources such as photo-multipliers, high-speed mass spectrometers, ion chambers, ans flame and beta-ray ionization detectors. Other applications include transient current measurements, noise studies and flash filament testing. This example is identical to the Keithley model 416 picoammeter (2008.0209) except that the 417 has provides a suppression current at the input up to 1000 times full scale on most ranges. This permits a full-scale display of 0.1% variations of a signal or suppression of a steady background signal (Ref. 2).

Notes sur la région

Inconnu

Détails

Marques

Black lettering on picoammeter front reads '417 HIGH OUTPUT PICOAMMETER'/ Black lettering on input head casing reads '4170 INPUT HEAD'/ Label on back reads 'K [logo] 40264/ KEITHLEY INSTRUMENTS/ INC. CLEVELAND OHIO USA'/ Black lettering for control functions on front and back

Manque

Plug of electrical cord

Fini

Glossy grey painted casing front/ Metallic grey casing sides, top, back, underside/ Black meter casing with white face/ Black painted and brushed metal controls with colourless synthetic dials/ Black synthetic cords and parts/ Gold coloured connector

Décoration

Black 'K' logo on input head