Dollond Pocket Telescope

Dual-Power Pocket Telescope

Signature

Dollond, London

Date

Late 1700s

Number of Draws

Dimensions

English

Metric

Main Tube Length

3.0in

77mm

Main Tube Diameter

1.4in

35mm

Total Length

4.8in

121mm

Closed Length

3.7in

93mm

Objective Clear Aperture Diameter

1.2in

30mm

Description

This monocular has a round parallel brass barrel that may have had a covering. It has a screw-on objective lens cap. The objective is an achromatic doublet. It has one brass draw (with no retention) and two single eye lenses. They are used one at a time by sliding a pin on the face of the eyecup to either position "1" or "2." These two lenses are mounted in a small metal plate inside the eyecup and pivot from one position to the other. There are two lines scribed around the draw and they are also numbered "1" and "2." The eye lens and draw set at position "1" gives approximately 3X magnification and at position "2" about 6X. It has a flared eyecup and when the sliding pin is set between "1" and "2," the pivoting lens plate served as a cover for the eye lenses. It is signed "Dollond London" on the draw, with the eyecup to the left.

College of Optical Sciences
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