Wire for Filar Micrometer

Astronomy

Accession Number: 2018.ast.59

Description:

This is a small rectangular box containing a broken fine gold thread about 4.5cm long. The thread was formerly supported on cardboard supports. Only one end of the thread is now in the right place. The thread is thicker at each end and appears silvery. The box appears to have originally contained three of these threads.

Also in the box there is a small leaflet giving directions on how to remove each gold thread without breaking it.

Primary Materials: Cardboard; Metal: Gold, Other

Markings:

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

“0.0007 AU STRIP 24K”

Written on the top of the box in coloured pencil: “Std 66 44”

Dimensions (cm):

Box: Height = 2.2, Width = 4, Length = 7.8.

Function:

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

Condition:

Poor: While the box is in good condition, the wire has broken and is curled up in one corner of the box.

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.