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Mariner's quadrant
Mariner’s quadrant with an engraved scale along the circular edge of the instrument, from 0° to 90° by 1°. Every five degree line has been extended to the apex of the instrument.
A polished brass quarter circle with two sights on the right-hand edge. The back of the instrument is blank apart from a thinly engraved circle with a diameter of 108 mm. The plumb bob is probably a later replacement.
The mariner's quadrant is a simple instrument that enabled navigators to determine their latitude (position north-south). To use the instrument, the sun or the pole star is observed through the sights and the line with the plumb bob marks the altitude of the celestial body above the horizon in degrees along the curved scale. The instrument was developed from the astronomical quadrant, which was known to ancient Greek astronomers and was used in navigation by the mid-15th century. The instrument can also be used for surveying.
A polished brass quarter circle with two sights on the right-hand edge. The back of the instrument is blank apart from a thinly engraved circle with a diameter of 108 mm. The plumb bob is probably a later replacement.
The mariner's quadrant is a simple instrument that enabled navigators to determine their latitude (position north-south). To use the instrument, the sun or the pole star is observed through the sights and the line with the plumb bob marks the altitude of the celestial body above the horizon in degrees along the curved scale. The instrument was developed from the astronomical quadrant, which was known to ancient Greek astronomers and was used in navigation by the mid-15th century. The instrument can also be used for surveying.
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Object details
| ID: | NAV1053 |
|---|---|
| Collection: | Astronomical and navigational instruments |
| Type: | Mariner's quadrant |
| Materials: | Brass |
| Display location: | Not on display |
| Creator: | Unknown |
| Date made: | circa 1600 |
| Credit: | National Maritime Museum, Greenwich, London. Caird Fund. |
| Measurements: | Overall: 10 mm x 180 mm x 250 mm |