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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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