Gregorian Reflecting Telescope

Astronomy

Accession Number: 2012.ast.5

Description:

This is a brass telescope with cover, brass pedestal, two objectives, and steel box containing additional reflecting mirror, all inside a wooden box with felt lined holders for the objects.

The telescope is a 61.5 cm (length) by 11 cm (diameter) brass tube, open on end (can be covered). Inside the telescope on the bottom is a 10 cm mirror with a hole in the middle and at the top, a small reflecting mirror is held in line with the bottom aperture. The brass is painted black on the inside. The outside has adjusting knob and smaller cover, which when removed allows for objectives to be attached.

The telescope fits on three legged brass pedestal (height 42cm). Additional reflecting mirror is housed in a steel box that appears to be of later construction. Both reflecting mirrors (inside telescope and additional) have hand written degrees of concavity.

Alternative Name: Gregorian Telescope

Primary Materials:

Metal: Copper Alloy, Glass, Metal: Iron Alloy, Wood, Textile: Felt

Markings:

Engraved in bold print on the bottom of telescope is: “Bate London”.

The label on the inside lid of box reads: “Mathematical instrument maker, by appointment of his majesty’s Hon’ble Board Excise, R.B. Bate, Mathematical, Optical & Philosophical Instruments, Wholesale Retail & for Exportation, 17 Poultry, London.”

Hand written on the back of the small reflecting mirror inside the telescope is: “50 &88 Concave”. Similarly, the additional reflecting mirror has written: “114 & 200”.

Dimensions (cm):

Box: Length = 67.2, Width = 25.4, Height = 14.5; Telescope: Length = 61.5, Diameter = 11.5; Pedestal: Length = 42, Width = 32, Height = 32; Additional Mirror = Length = 10, Width = 7, Height = 4.5; Objective 1: Length = 10.5. Diameter = 4.0; Objective 2: Length = 7.0, Diameter = 4.0

Function:

A telescope is an instrument for magnifying distant objects. The Gregorian telescope incorporates two concave mirrors.

Condition:

Excellent: The box of the telescope is in excellent condition. It has a few marks and stains on the top of the box, and scratches underneath the latches of the box. Over the front of the box on the right hand side the varnish on thee box has been partly removed, and residue left behind, where a wide strip of tape has been applied and later removed.

The instrument is in excellent condition. The surface of the brass exhibits some small marks and scratches. Under the main tube, there are some long scratches towards the objective end of the tube. There is some rainbow-coloured discolouration on the surface of all the brass components, and patches of patches of corrosion along the length of the tube. On the whole, the brass is shiny and bright.

The paper label on the inside of the box is yellowed and peeling slightly around the edges, but in good condition.

Associated Instruments:

Manufacturer: R. B. Bate, London

Date of Manufacture: c. 1830

Provenance:

University of Toronto Department of Astronomy & Astrophysics