Unknown, 1710 c.
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Photo

photo - whole telescope
Basic Info

Maker: Unknown

Year: 1710 c.

Year Range: 1700-1740

Year Notes:

Manufacturing Location: England

Signature:

Signature Notes:

Inscriptions:

No stand present.

Collection: National Maritime Museum

Accession #: NAV1523

Sources:

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).

Provenance:

Caird Collection.

Length (open): 600

Length (closed): 225

F-ratio:

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

Eyepieces

Notes: