SIGHTING QUADRANT FOR DISTANCE RANGING OF TALL SHIPS, ETC.

SIGHTING QUADRANT FOR DISTANCE RANGING OF TALL SHIPS, ETC.

Stock Number: 10192

$1350.

For sale, antique English brass sighting quadrant, which can be used for astronomical or surveying angular altitudes. However, there is a small scale on the reverse which identifies this for maritime use.

Dimensions

6-1/4 inches (16 cm) tall

Circa

c. early 19th century

Country of manufacture

UK and Ireland

Categories: Maritime, Navigational instruments

Description

SIGHTING QUADRANT, English, c. early 19th century. This all-brass instrument stands 6-1/4″ (16 cm) tall, with cross-hair equipped sighting tube moving in altitude over the 0(1)90 degree quadrant, and swinging freely in azimuth on the short pillar mount. Sighting horizontally the scale reads 0°; vertically, 90°. Thus we have a straightforward astronomical quadrant measuring angular altitudes of celestial bodies as well as topographic features, buildings, etc. But a small scale, with index pointer, on the reverse tells a further story, and speaks of probable maritime use. Covering altitudes of less than 8°, this scale is divided from 500 yards to 2000 yards and beyond. The 500 yard mark corresponds to about 7.°25, which is the angular height of an object about 190 feet tall, at that distance. Few things on land have such a typical height but it is a reasonable estimate for the mast heights of the tallest sailing ships. For example, we find in 1830 the 1300 ton merchant ship had a main mast of 179 feet. Contained in a somewhat stained simple pine box, this unusual instrument is in very fine condition.

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US TESSERACT

David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at mail@etesseract.com.

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