Maker: Dollond

Year: 1775 c.25

Year Range: -

Year Notes:

Manufacturing Location:

Signature: Dollond / London

Signature Notes:

Inscriptions:

Stand present.

Collection: National Maritime Museum

Accession #: AST0933

Sources:

Royal Museums Greenwich. "Miniature refractor telescope". http://collections.rmg.co.uk/collections/objects/11095.html. Images and text.
[Accessed: June 2016].

Public Notes:

"A late 18th century lacquered brass miniature refracting telescope, which is the smallest telescope in the Greenwich collection. Even so, its eyepiece has a rotating wheel of four differing lens powers. The telescope is mounted on a column support with three cabriole legs and stands about 4 inches high. The whole instrument can be easily dismantled and stored within the original fishskin-covered card case. The lens is covered by a screw-on cap. When John Dollond and his son Peter started an optical instrument company in the early 18th century, astronomical observations suffered because of the poor quality of glass available for telescope lenses. John Dollond worked with higher-quality glass to produce a lens free from chromatic aberration (distortion of an image with fringes of coloured light). Within ten years, every observatory in Europe had upgraded its telescopes with this achromatic lens. The Dollond name is still familiar in Britain as part of a chain of opticians" (Royal Museums Greenwich).

Length (open): 116

Length (closed):

F-ratio:

Exit pupil:

Object status:

Objective type: unconfirmed

Optical style

Physical style

Functional style

Materials: fish skin, pasteboard, glass, brass

Drawtube data:

Drawtube notes:

Diameter: 41 mm

Objective Data

Eyepieces

Notes: