Unknown Optical Coloured Filters

Astronomy

Accession Number: 2019.ast.264.1-2

Description:

These are two similar rectangular metal pieces with a row of eight circular openings along their length, grouped at one end of the rectangle. Each of the openings has a brass threaded interior. Screwed into all the openings on 2019.ast.264.1 and six of the openings on 2019.ast.264.2 are circular differently-coloured glass filters mounted in brass surrounds. Aligned with each opening there is an indentation along one side of the rectangular metal piece.

Affixed by screws at one end of both of these metal pieces there is a small metal attachment that has a solid section that sticks out above the main metal section.

Primary Materials:

Metal: Iron Alloy, Metal: Copper Alloy, Glass.

Markings:

2019.ast.264.1: Engraved at the end of the main metal piece, by the brass attachment: “B”

2019.ast.264.2: Engraved at the end of the main metal piece, by the brass attachment: “H”

Dimensions (cm):

Both: Height = 1.5, Width = 7, Length = 33.

Condition:

Very Good: The surface of the silver metal is patchily oxidized and dulled along its length, and covered in fine scratches. There are striations along both larger faces and one narrow face of the rectangular metal pieces, suggesting the instrument has been repeatedly slid into a slot. The brass sections are dulled but in good condition.

Manufacturer: Locally made

Date of Manufacture: Early-Mid 20th Century

Provenance:

These artifacts was collected from a room marked “Instrument Room” on the 15th story of the McLennan Physical Laboratory, U of T in November 2019, along with two other objects (2019.ast.264.1-2). Prior to its collection, its history is unknown, but they may have been constructed for use at the David Dunlap Observatory in Richmond Hill.