Nairne Reflecting Telescope

Signature

Nairne, London

Date

circa 1770

Dimensions

English

Metric

Main Tube Length

13.7in

348mm

Main Tube Diameter

2.9in

73mm

Total Length

29.3in

432mm

Height of Base

11.0in

280mm

Primary Mirror Diameter

2.7in

68mm

Description

This telescope has a small brass cylindrical barrel. The primary speculum mirror is a concave paraboloid, with a central hole, and is kept in place at the rear 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 for several inches along the front interior part of the barrel. This configuration of primary and secondary mirrors is called Gregorian. The focusing thumbscrew, at the eyepiece end of the barrel, is the long shank design, attaching to the secondary mirror carrier through a slot near the front end of the barrel. The eyepiece tube screws into a hole in the center of the backing plate, which holds the primary mirror in place. The two-lens eyepiece is the Huygens type. The Telescope is signed "Nairne London" in large script on the top of the barrel, at the back end, with the eyepiece to the left. The scope mounts on a brass column, with horizontal and vertical swivel joints, to a folding tripod with cabriole legs. It comes with a fitted mahogany case.

College of Optical Sciences
The University of Arizona, 1630 East University Boulevard, Tucson, Arizona U.S.A. 85721-0094