General Information

Serial #

N/A

Part Number

1

Total Parts

1

AKA

N/A

Patents

N/A

General Description

BRASS & GLASS CONSTRUCTION; WOODEN CASE. Ebonite knobs. Paper charts

Dimensions

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

Length

28.7 cm

Width

21.5 cm

Height

15.0 cm

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Physics

Category

Light & electromagnetic radiation

Sub-Category

N/A

Manufacturer

AKA

Brashear

Country

United States of America

State/Province

Pennsylvania

City

Allegheny

Context

Country

Canada

State/Province

Ontario

Period

USED 1905- C. 1930.

Canada

USED WITH THE 15-INCH REFRACTING TELESCOPE AT THE DOMINION OBSERVATORY, OTTAWA ONT. (SEE 700212)

Function

TO DETERMINE THE MAGNITUDE (BRIGHTNESS) OF STARS USING AN OPTICAL WEDGE ARRANGEMENT.

Technical

WEDGE PATTERN PHOTOMETER DESIGNED & MFD BY BRASHEAR. BY COMPARING THE POSITION ON THE WEDGE-SHAPED STRIP OF DARK GLASS AT WHICH THE LIGHT FROM THE STARS IS COMPLETELY EXTINGUISHED, THEIR MAGNITUDE MAY BE DETERMINED. UP TO FORTYOBSERVATIONS COULD BE RECORDED ON THIS INSTRUMENT, MORE EFFICIENTLY AND ACCURATELY, THAN IF RECORDED MANUALLY. IT'S ACCURACY WAS, HOWEVER, WEATHER & OBSERVER DEPENDANT. (REF. 1)

Area Notes

Unknown

Details

Markings

None on photometer, save scale divided 15 to 1, in single increments. Engraved plate fixed inside PT case lid reads " John A. Brashear Co. Ltd./ Allegheny, Pa./ U.S.A ". Recording paper bears columns labelled 15 to 0 (top, left to right), and 1 to 37 ( down right side of page).

Missing

NONE. USED WITH NORMAL TELESCOPE EYEPIECES. From CA of 11/08/2001 by David Daley: No - Complete

Finish

LACQUERED BRASS, SAVE SILVER METAL SCALE (SILVER ?); SOME FITTINGS HAVE BLUED FINISH. CASE HAS DARK BROWN STAINED & VARNISHED FINISH.

Decoration

N/A