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Portable telescope
The barrel of this non-achromatic telescope is made of vellum that has been decorated with gold-tooled motifs. There are seven draw tubes made of white vellum with gold-tooled decoration on the collars. The lenses are set in turned ebony mounts and the objective lens has a screw-on ebony cap.
Black stop lines around the draw tubes indicate an optimum working length of over 1700 mm. The length of the telescope indicates that it was to be used for astronomical observations in conjunction with some form of support to keep it steady. The telescope had to be long since it was only possible at this time to produce accurate lenses with fairly long focal lengths.
The style of the telescope suggests it was made in England around 1700. In particular, the style is similar to that of examples made by the London instrument maker Christopher Cock (worked about 1697).
Black stop lines around the draw tubes indicate an optimum working length of over 1700 mm. The length of the telescope indicates that it was to be used for astronomical observations in conjunction with some form of support to keep it steady. The telescope had to be long since it was only possible at this time to produce accurate lenses with fairly long focal lengths.
The style of the telescope suggests it was made in England around 1700. In particular, the style is similar to that of examples made by the London instrument maker Christopher Cock (worked about 1697).
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Object Details
| ID: | NAV1567 |
|---|---|
| Collection: | Astronomical and navigational instruments |
| Type: | Portable telescope |
| Display location: | Not on display |
| Creator: | Unknown |
| Date made: | circa 1700 |
| Credit: | National Maritime Museum, Greenwich, London, Caird Collection |
| Measurements: | Length: 554 mm (closed); 1718 mm (open to stop lines, max.); Diameter: 65 mm (barrel), 70 mm (max.) |