Light Table

Astronomy

Accession Number: 2019.ast.234

Description:

This item is contained in an open rectangular wooden box with rounded rectangle openings at the end for carrying the box.

The instrument is partially disassembled. It consists of a wooden frame, a rectangular mirror, and a rectangular ground glass screen, contained in a cardboard container. When assembled, the frame supports the mirror and screen, which both fit into cut rims in the wooden frame. The mirror is held at a shallow angle resting from the floor to about ten centimeters off the ground; this is raised by two wooden feet. The ground glass screen is held at a steeper angle rising from the feet end of the instrument, forming about a 30-degree angle with the mirror. The screen is held at a comfortable viewing angle for the user.

Primary Materials: Wood, Glass, Metal (Mirror)

Markings:

Written in black marker on the cardboard packaging for the ground glass screen: “GROUND GLASS SCREEN”

On a red sticker stuck to the same packaging: “FRAGILE HANDLE WITH CARE”

Dimensions (cm):

Box: Height = 24.3, Width = 32.5, Length = 51.

Function:

The easy viewing of glass plate photographs and images. The mirror directs light towards the ground glass plate, which dissipates light permitting the viewing of glass plate slides and photographs without the need for a projector.

Condition:

Very Good: The box (likely not original) that contains this item is very worn, and covered with chips, particularly around the top edges and corners. There is a significant crack along the length of one side. However, it appears strong and intact.

The wooden frame of the instrument is dusty but in very good condition. There are a few chips and dents along the edges of the instrument. The mirror is very dirty and dusty, but in good condition, with a few minor spots of corrosion on the metal base. The ground glass piece is in excellent condition.

Date of Manufacture: Early-Mid 20th Century

Provenance:

This artifact was kept at the David Dunlap Observatory until 2009. Upon the sale of the Observatory in that year, it was moved to the University of Toronto’s Department of Astronomy & Astrophysics at the St George Campus. In 2017 it was moved to a new storage location in McLennan Physical Laboratories.