This is a transparent yellow glass disk 16.5cm in diameter and 0.5cm thick. It is wrapped in a piece of cream-coloured cloth and plastic with a masking tape label stuck around it.
Accession Number: 2019.ast.215 (DAA-0110)
Primary Materials: Glass, Fabric (Cotton?), Plastic.
Handwritten on the masking tape: “YELLOW FILTER OPTICAL QU[ality?] GLASS”
Dimensions (cm): Filter: Height = 0.5, Diameter = 16.5.
A yellow filter absorbs all colours of light except yellow.
Very Good: The plastic wrapping of the object is ripped and crinkled. The masking tape has been broken up when the package has been opened. The fabric is dirty and somewhat yellowed.
Date of Manufacture: 20th Century
This object was kept at the David Dunlap Observatory 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.
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