Dollond, 1760 c.
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Photo

photo - whole telescope
Basic Info

Maker: Dollond

Year: 1760 c.

Year Range: -

Year Notes:

Manufacturing Location: London, England

Signature: DOLLOND

Signature Notes:

Inscriptions:

No stand present.

Collection: National Maritime Museum

Accession #: NAV1534

Sources:

Royal Museums Greenwich. "spy glass telescope". http://collections.rmg.co.uk/collections/objects/43746.html [Accessed: June 2016].

Public Notes:

"Small Galilean telescopes like this were made as personal accessories to fit in the pocket. The barrel of this example is made of tortoiseshell and there is a single draw tube of silvered brass. The lenses are set in turned ivory mounts with the maker's name engraved on the objective lens mount. The original case, which is made of sharkskin over wood, also survives" (Royal Museums Greenwich).

Length (open): 59

Length (closed): 46

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: singlet

Optical style galilean

Physical style spyglass and pocket

Functional style

Materials: tortoiseshell, ivory, glass, brass

Optical/Lab Data

Drawtube data:

Drawtube notes:

Objective Data

Eyepieces

Notes:

WavelengthParaxial70%Whole
652 ± -0.5 ± 0.1 ± ±
575 ± 0 ± ±
482 ± -2.0 ± 0.1 ± ±