Maker: Unknown

Year: 1710 c.

Year Range: -

Year Notes:

Manufacturing Location: England

Signature:

Signature Notes:

Inscriptions:

No stand present.

Collection: National Maritime Museum

Accession #: NAV1544

Sources:

Royal Museums Greenwich. "Non-achromatic telescope". http://collections.rmg.co.uk/collections/objects/43756.html [Accessed: June 2016].

Public Notes:

"The barrel of this non-achromatic telescope is made of vellum decorated with gold-tooled motifs that are now only just visible. The two draw tubes are also made of vellum but are not decorated. The brass fittings include a sliding eyepiece cover. In the early 18th century it was only possible to make lenses with a relatively long focal length meaning that telescopes had to be very long - this example can extend to over 2000 mm. Stop lines have been marked on each draw tube to indicate its optimum working length. An inscription on one of the tubes that holds the correcting lenses states, 'These 2 Glasses... to be taken out when used at night'. This would reduce the amount of light lost, but would also mean that the observed image was inverted" (Royal Museums Greenwich).

Length (open): 2338

Length (closed): 1193

F-ratio:

Exit pupil:

Object status:

Objective type: singlet

Optical style

Physical style

Functional style day or night

Materials: vellum, brass, glass, gold tooling, pasteboard

Drawtube data:

Drawtube notes:

Diameter: 75 mm

Objective Data

Eyepieces

Notes: