Wire for Filar Micrometer

Astronomy

Accession Number: 2018.ast.54

Description:

This is a small rectangular cardboard box containing a single fine (0.0007″) gold thread 5.5cm long. The thread is strung between cardboard supports and each end is slightly thicker and appears silver.

Alternative Name: Thread

Primary Materials: Cardboard, Metal: Gold, Other

Markings:

On the box label”LEEDS & NORTHRUP COMPANY
4901 STENTON AVENUE
PHILADELPHIA, PA”

“0.0007 AU STRIP 24K”

“PACKED SUSPENSIONS”

In pencil on the box: “Job #287-L
1-Std.547-F”

Dimensions (cm): Height = 2, Width = 3.5, Length = 15.5,

Function:

This wire is for use in a filar micrometer used for taking measurements between objects in astronomical instruments.

Condition:

Good: The box is somewhat worn. One wire remains; it appears the box originally held two. The wire is intact.

Manufacturer: Leeds & Northrup Company

Date of Manufacture: Early-Mid 20th Century

Provenance:

This object was likely moved from the David Dunlap Observatory in Richmond Hill in 2008, upon the sale of the observatory. It was stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.