Pallant Gregorian Telescope

Signature

Pallant, London

Date

circa 1825

Dimensions

English

Metric

Main Tube Length

11.5in

292mm

Main Tube Diameter

2.8in

70mm

Total Length

14.0in

357mm

Closed Length

20.8in

62mm

Primary Mirror Diameter

2.4in

30mm

Description

This telescope has a lacquered brass cylindrical barrel, with a push-on cap. The primary mirror is a concave paraboloid, with a central hole, and is kept in position at the rear end of the barrel with a screw-in backing plate. The small secondary mirror is a concave ellipsoid. It is attached by a slender arm to a screw-driven carrier which slides on guide rails fixed along the forward interior part of the barrel. This configuration of primary and secondary mirrors is called Gregorian. The focusing screw is the short shank design, attaching to the secondary mirror carrier by a slot near the back end of the barrel. The short eyepiece tube screws into a hole in the center of the backing plate, which holds the primary mirror in place. The eyepiece is a Huygens type and has two lenses. There is a slightly flared eyecup that screws onto the end of this tube and it has a stop with a very small aperture. This stop blocks extraneous light from the inside of the barrel. The telescope mounts on a brass stand with folding scroll-footed cabriole legs. The scope is not signed by the maker. However, it comes with a fitted mahogany box which has a label inside the lid reading "Pallant, Optician, 51 Strand London W.C."

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