General Information

Serial #

149

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

metal mechanism, base, casing cover and parts/ casing cover has synthetic window and synthetic dome with metal cover/ brass drum and parts/ liquid spirit in glass & metal level housing/ paper chart

Dimensions

Note: These reflect the general size for storage and are not necessarily representative of the object's true dimensions.

Length

34.0 cm

Width

18.6 cm

Height

26.5 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Meteorology

Category

Sunshine intensity & duration measurement

Sub-Category

N/A

Manufacturer

AKA

Casella

Country

England

State/Province

Unknown

City

London

Context

Country

Canada

State/Province

Unknown

Period

at least 1960's to early 1980's; this instrument was apparently in use for 50 years (Ref. 10)

Canada

A type of actinograph possibly used by the Meteorological Service of Canada. The MSC radiation equipment manuals of the 1950's and 1960's (Refs. 5-6) list an unidentified Robitzch type actinograph (formerly in use but by then obsolete) as well the MSC actinograph like 1987.0742 as part of the MSC's complement of radiation equipment. Actinographs are not mentioned in any of the MSC manuals of the 1970's to 1990's (Refs.7-8). Part of a large collection of meteorological instruments acquired from the Meteorological Service of Canada (previously Atmospheric Environment Service) by the CSTM since 1967. MSC is the government agency responsible for collecting and disseminating meteorological data and forecasts in Canada. It was founded in 1871 in Toronto where it is still headquartered. The MSC was originally on the University of Toronto downtown campus but moved to Downsview in 1971 on land owned by UofT. The headquarters houses laboratories, research facilities and calibration and instrument maintenance facilities (now largely contracted out).

Function

An instrument which records on a chart the shortwave radiation received from the sun and sky on a horizontal surface. It is usually used for obtaining daily totals of solar radiation because it is slower to respond and is less accurate than electrical instruments.

Technical

A Casella actinograph which uses the temperature difference between a black and white bimetals to activate the pen on a mechanical recorder. 1987.0743 is the MSC designed version of the actinograph. They both measure the global solar radiation but are slower to respond and much less accurate than the pyranometers (Ref. 1). This instrument appears in Casella's 1958 and 1963 catalogues (Refs. 2-3) and was designed by the British Meteorological Office. It closely resembles the Robitzch actinograph described in the British Meteorological Office 1982 `Handbook of Meteorological Instruments`(Ref. 4). The sensor consists of two parallel, rectangular strips of bimetal covered by white painted shields between which is placed a similar strip of blackened bimetal, uncovered. At one end the black strip is connected to a lever mechanism and the movements of the strip are recorded by a pen on a chart on a revolving drum. The combination of black and shaded strips is designed to provide compensation for ambient temperature changes which might distort the readings. The sensor is exposed to radiation through a hemispherical glass dome mounted in the casing cover (Refs. 2-4).

Area Notes

Unknown

Details

Markings

incised lettering on brass plate across front reads 'MADE IN ENGLAND CASELLA [CASELLA/LONDON] (logo) LONDON 149'

Missing

unknown

Finish

black sensor on white painted mount/ white painted base, casing cover/ brushed, plated, gold coloured, black painted and metallic parts/ colourless transparent synthetic/ white paper with green markings

Decoration

N/A