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Other Dollond Instruments

 

Dual-Power Pocket Telescope

Signature Dollond, London

Date Late 1700s
Number of Draws 1
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. 

 


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