General Information

Serial #

25085

Part Number

1

Total Parts

4

AKA

N/A

Patents

N/A

General Description

Aluminum (possibly) ring, screw; brass (possibly) tip

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

6.3 cm

Thickness

N/A

Weight

N/A

Diameter

5.3 cm

Volume

N/A

Lexicon

Group

Astronomy

Category

Miscellaneous

Sub-Category

N/A

Manufacturer

AKA

NALDER

Country

England

State/Province

Unknown

City

Westminster

Context

Country

Canada

State/Province

Ontario

Period

c. 1905-1970

Canada

A precision measuring device used at the Dominion Observatory, Ottawa (c. 1905-1970). This spherometer may have been used on a variety of astronomy, survey or metrology instruments employed there.

Function

A spherometer is a type of micrometer that measures the radius of a sphere. It is commonly used in optics to determine the curvature lenses.

Technical

The instrument is placed on ant part of a mirror or lens and the central micrometric screw is turned carefully until it just touches the lens or mirror surface. The measurement is the reading on the vernier scale. This instrument was designed to measure small spherical curvatures. (Taken from the worksheet)

Area Notes

Unknown

Details

Markings

There is a scale around the circumference of the ring from 0-199, marked in single units and numbered every 10.

Missing

Appears complete.

Finish

Silver-coloured metal with some copper-coloured parts.

Decoration

N/A