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Pocket sextant
The sextant consists of circular polished brass plates with a lid that when screwed on the back of the instrument serves as the handle. The index arm is moved by a milled screw on the upper plate. The instrument has two index shades in red and green, which are moved by levers. Horizon-glass adjustment is made by a milled key shipped in the upper plate.
Attached to the sextant is a single lens magnifier on a 45mm swivelling arm. The telescope is 65 mm in length with an erect image and an angled bracket for attaching it to the instrument by a milled screw. It has a sliding pinhole shutter.
The instrument has an inlaid silver scale from -5° to 170° by 30 arcminutes, measuring to 139° (the digits are read from the pivot). The sextant has a silver vernier, reading to 1 arcminute, with zero at the left.
The sextant is contained in a fitted leather case, lined with velvet.
Attached to the sextant is a single lens magnifier on a 45mm swivelling arm. The telescope is 65 mm in length with an erect image and an angled bracket for attaching it to the instrument by a milled screw. It has a sliding pinhole shutter.
The instrument has an inlaid silver scale from -5° to 170° by 30 arcminutes, measuring to 139° (the digits are read from the pivot). The sextant has a silver vernier, reading to 1 arcminute, with zero at the left.
The sextant is contained in a fitted leather case, lined with velvet.
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Object Details
| ID: | NAV1150 |
|---|---|
| Collection: | Astronomical and navigational instruments |
| Type: | Box sextant |
| Display location: | Not on display |
| Creator: | Unknown |
| Date made: | circa 1850 |
| Credit: | National Maritime Museum, Greenwich, London |
| Measurements: | Overall: 28 mm; Diameter: 70 mm |
| Parts: | Pocket sextant |