Maker: Unknown

Year: 1720 c.

Year Range: 1670-1740

Year Notes:

Manufacturing Location: France

Signature:

Signature Notes:

Inscriptions:

No stand present.

Collection: National Maritime Museum

Accession #: NAV1494

Sources:

Royal Museums Greenwich. "Hand-held telescope: telescopes". http://collections.rmg.co.uk/collections/objects/43706.html [Accessed: June 2016].

Public Notes:

"The design and style of this non-achromatic telescope suggest that it is French. The barrel and lens hoods are covered in red leather decorated with gold-tooled motifs. The five draw tubes are made of green waxed paper and are also decorated with gold-tooled motifs. The other fittings are of turned wood. The large number of draw tubes allows the telescope to be extended to a great length. This was necessary in this period, when telescopes used lenses with long focal lengths to avoid the problems of chromatic aberration - the appearance of coloured fringes around the image. The black stop lines on each of the draw tubes indicate that the optimum working length of this telescope was over 1500 mm" (Royal Museums Greenwich).

Eyepiece Notes:
3-lens eyepiece, consisting of a 2-lens component inserted into last draw, with lenses equally separated.

Length (open): 1500

Length (closed): 650

F-ratio:

Exit pupil:

Object status:

Objective type: singlet

Optical style terrestrial

Physical style

Functional style

Materials: leather, parchment, wood, glass, gold tooling, pasteboard

Drawtube data:

Drawtube notes:

Objective Data

Eyepieces

Notes: