Backstaff - Wikipedia
The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the Sun or Moon. When observing the Sun, users kept the Sun to their back (hence the name) and observed the shadow cast by the upper vane on a horizon vane.
Backstaff - Ages of Exploration - Mariners' Museum and Park
Backstaff is the name given to any instrument that measures the altitude of the sun by the projection of a shadow. Invented by John Davis in the 16th century, it became a useful tool for navigators at sea.
ION Museum: Back-staff
Item History: The back-staff, also known as the Davis quadrant (called a quadrant because it could measure up to 90º), was the first instrument specifically designed for finding latitude at sea.
Backstaff - (US History – Before 1865) - Vocab, Definition ...
The backstaff is a navigational instrument that was invented in the late 16th century, allowing sailors to measure the altitude of the sun without directly looking at it.
backstaff | Objects | The Collection of Historical Scientific ...
This is a standard English-style backstaff. The small semi-circle scale is graduated from 0-65°, divided in degrees. A small "4" is marked on this arc and the top is decorated with small stars. The large graduated limb has two distinct scales: 65°-90° and 0-25°, the latter divided every 5'.
Backstaff | nautical instrument | Britannica
sextant, instrument for determining the angle between the horizon and a celestial body such as the Sun, the Moon, or a star, used in celestial navigation to determine latitude and longitude. The device consists of an arc of a circle, marked off in degrees, and a movable radial arm pivoted at the centre of the circle.
The backstaff is a navigational instrument that was used to measure the altitude of a celestial body, in particular the sun or moon. When observing the sun, users kept the sun to their back (hence the name) and observed the shadow cast by the upper vane on a horizon vane.
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