Light Table

Astronomy

Accession Number: 2019.ast.231.1-2

Description:

2019.ast.231.1 – A rectangular wooden box with part of one side open, and a glass top. About two centimeters under the glass top there is an opaque plate with a piece of paper, folded, lying on top of it. Underneath this, and accessible through the open section of the side is another glass plate slanted at a diagonal angle in the box, and a light bulb in a ceramic base that is fixed to one end of the table so the light bulb is held horizontally. with a long brown coiled cable with textile insulation. At the end of this is a two-pronged plug.

2019.ast.231.2 – With the object, there is a 1939 photographic plate depicting a globular cluster inside a paper envelope.

Primary Materials: Wood, Glass.

Markings:

On a sticker affixed to the top glass panel: “LIGHT TABLE USED BY H.S.H.”

On the paper envelope: “NGC 6205
4817
9490.597

1939 Aug. 14 EST
21 05 – 21 41
(clouds)

2 14 W”

On a label with the object: “Light Table
Used by Helen Sawyer Hogg with one of her photographic plates from 1939 of Messier 13 (M13, NGC 6205), also called the “Great Globular Cluster in Hercules”, one of the most prominent and best known globulars of the Northern celestial hemisphere.”

Dimensions (cm):

Box: Height = 13, Width = 15.2, Length = 28; Plate: Height = 0.2, Width = 9.2, Length = 12.

Function:

The easy viewing of glass plate photographs and images. The lightbulb and translucent glass surface provides a back-lit surface for the viewing of two or three 3″ slides. The clear glass is removable and may provide separation from the hot surface next to the lightbulb.

The object was once on display; the plate with the object was used to demonstrate the function of the light table.

Condition:

Very Good: The box is in good condition. The glass plates are intact, although the top section has some residue in the centre and the affixed sticker. The wooden surfaces are in very good condition. The piece of paper on top of the translucent glass is yellowed, particularly around the edges.

Manufacturer: Unknown

Date of Manufacture: c. 1920s-1940s

Provenance:

According to an affixed label, this item was used by University of Toronto astronomer Dr. Helen Sawyer Hogg, possibly at the David Dunlap Observatory in Richmond Hill. If so, the table was kept at, or moved to, the David Dunlap Observatory, where it stayed until 2009. Upon the sale of the Observatory, 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.

Historical Notes:

According to an affixed label, this table was used by University of Toronto astronomer Professor Helen Sawyer Hogg, who moved to the David Dunlap Observatory in Richmond Hill when her husband received a job there in 1935. She continued her work, including taking the included 1939 plate of the globular cluster M13, while also traveling for her research. She took on teaching duties at the university during WWII and later advanced to full professor in astronomy at the Department of Astronomy at the University of Toronto.