Unknown, 1710 c.
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photo - whole telescope
Basic Info

Maker: Unknown

Year: 1710 c.

Year Range: 1700-1740

Year Notes:

Manufacturing Location: England


Signature Notes:


No stand present.

Collection: National Maritime Museum

Accession #: NAV1523


Royal Museums Greenwich. "Non-achromatic telescope". http://collections.rmg.co.uk/collections/objects/43735.html [Accessed: June 2016].

Public Notes:

This telescope has a shagreen case cover attached to the main draw, along with shagreen end caps.

Year Notes:
Mottled leather suggests 1700-1740. Rayskin is more common at a later date. Blotched, mottled leather pattern suggests early 18th century date.

Objective Notes:
Focal length measured directly in collimated beam. Grozed objective.

Eyepiece Notes:
Eyepiece consists of 2 lenses in a removable component, plus an ocular in last draw. The fittings are made of ivory and the lenses are grozed.

Museum Description:
"The three draw tubes of this non-achromatic telescope are made of mottled vellum decorated with gold-tooled motifs. The barrel is covered with rayskin that has been dyed, as are the hinged cover for the objective lens and the slide-on eyepiece cover. The other fittings are made of turned ivory. Black stop lines on the draw tubes indicate the optimum working length of the telescope" (Royal Museums Greenwich).


Caird Collection.

Length (open): 600

Length (closed): 225


Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style terrestrial

Physical style

Functional style

Materials: shagreen, vellum, ivory, glass, pasteboard, rayskin, gold tooling

Optical/Lab Data

Drawtube data:

Drawtube notes:

Reinforcing rings starside on Draws 1 and 2. Ivory fittings for objective cell and ocular.

Objective Data

CA curvature (diopters): CB curvature (diopters): PD lens power (diopters): fD focal length (mm): t thickness (mm): free aperture (mm): full aperture (mm): nD refractive index: ν Abbe No.:
Lens 1 360.00