General Information

Serial #

6771/42

Part Number

2

Total Parts

2

AKA

N/A

Patents

N/A

General Description

Wooden case stained dark brown; fitted with khaki colour woven fabric carrying strap; hinged lid has brass fittings; brass hook closures; green felt pads on internal supports; paper label.

Dimensions

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

Length

N/A

Width

N/A

Height

N/A

Thickness

N/A

Weight

N/A

Diameter

N/A

Volume

N/A

Lexicon

Group

Astronomy

Category

Miscellaneous

Sub-Category

N/A

Manufacturer

AKA

Dominion Electric

Country

Unknown

State/Province

Unknown

City

Unknown

Context

Country

Canada

State/Province

Unknown

Period

This type of instrument probably used c. 1940s +; possibly also used earlier/later.

Canada

Unknown

Function

To contain, protect and identify contents when not in use.

Technical

An astro compass is generally a navigational tool used in aviation. In its most basic form, the astro compass consists of a base plate marked with the points of the compass, with a mechanism known as an equatorial drum mounted on it. On this drum is a set of adjustable sights and a scale of declination. More advanced versions may have built-in chronometers or default settings for bodies such as the Sun. To use the compass, the base plate is first levelled with the horizon then pointed roughly to what the user believes to be north. The equatorial drum is then tilted in relation to this base according to the local latitude. The sights are then set using the local hour angle and the declination of whatever astronomical body is being used. Once all these settings have been made, the astro compass is simply turned until the astronomical body is visible in the sights: it will then be precisely aligned to the points of the compass. Because of this procedure, an astro compass requires its user to be in possession of a nautical almanac or similar astronomical tables, one of its chief disadvantages (Ref. 1).

Area Notes

Unknown

Details

Markings

" FSSO NO. 88-C-770/ AN-5738-1" stencilled in off-white on lid. "ASTRO COMPASS MK. II/ REF. NO. 6A/1174/ CANADA/ DOMINION ELECTRIC PROTECTION COMPANY" stencilled on box front. "S/N 6771" and "974" printed by hand in black on box lid. "GFE/ PV-1" stamped in silver ink on lid. "PACKING/ Set course to South/ and place in box with/ Levels uppermost." printed on paper label fixed to inside of lid.

Missing

Appears complete.

Finish

Wooden case stained dark brown; fitted with khaki colour woven fabric carrying strap; hinged lid has brass fittings; brass hook closures; green felt pads on internal supports; paper label.

Decoration

N/A