Bausch & Lomb/Milton Roy Diffraction Grating

Astronomy

Accession Number: 2019.ast.119

Description:

This object is a rectangular diffraction grating inside a cardboard box with a red top and black bottom. The grating is packed in a large quantity of black foam cut to fit the grating.

The grating is rectangular and quite deep (4cm). A layer of glass, a cover, 1cm thick sits on the grating surface. Beneath this there is a block of clear material. In the centre of the top glass surface there is etched a Bausch & Lomb logo. On the rear side there is a green sticker giving information about the grating, including the grooves per mm and blaze angle. Most of this is unreadable.

Masking tape is wrapped around the upper rim of the grating, holding the glass cover on top of grating.

Primary Materials: Glass: Fused Silica, Metal: Iron Alloy

Markings:

On stickers on the front of the box: “Masterpieces of Precision from MILTON ROY COMPANY
Analytical Products Division”

“NOTICE:
STORE GRATING IN ENVIRONMENT
SUITABLE FOR SPECTROMETRIC
INSTRUMENTS.
355305-104”

On the surface of the cover: “B&L”

Handwritten in pencil around the edge of the grating: “199 – FUSED SILICA”
“?971-2-7-3-5”

Dimensions (cm):

Box: Length = 35.8, Width = 28.6, Height = 11.6

Function:

This is for use in spectroscopic work–the splitting of light into a spectrum and the subsequent analysis of that spectrum.

Condition:

Very Good: The box is in good condition, with signs of wear across the surface and some tearing at the corners; at one point the lid has been taped on.

The grating has signs of wear; the grating surface appears to be corroded in patches, but is relatively clear. The glass cover is scratched. The tape holding the lid on is peeling around the top, but intact.

Manufacturer: Milton Roy, Bausch & Lomb

Date of Manufacture: 1985-1995

Provenance:

The grating was moved from the David Dunlap Observatory in Richmond Hill in 2009, upon the sale of the observatory. They were stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.