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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.
Navigational instruments are instruments used by nautical navigators and pilots as tools of their trade. The purpose of navigation is to ascertain the present position and to determine the speed, direction , etc. to arrive at the port or point of destination.
All nautical instruments that measure the speed of a ship through water are known as logs. [2] This nomenclature dates back to the days of sail, when sailors attached a piece of lumber (a "log" of wood) to a rope knotted at regular intervals off the stern of a ship. Sailors counted the number of knots that passed through their hands in a given ...
1859 Helmsman's marine sandglass, in a four-column wood stand. A marine sandglass is a timepiece of simple design that is a relative of the common hourglass, a marine (nautical) instrument known since the 14th century (although reasonably presumed to be of very ancient use and origin).
A binnacle (/ ˈ b ɪ n ə k əl /) is a waist-high case or stand on the deck of a ship, generally mounted in front of the helmsman, in which navigational instruments are placed for easy and quick reference as well as to protect the delicate instruments.
Three Mariner's Astrolabes in the Museum of the Forte da Ponta da Bandeira; Lagos, Portugal. The mariner's astrolabe, also called sea astrolabe, was an inclinometer used to determine the latitude of a ship at sea by measuring the sun's noon altitude (declination) or the meridian altitude of a star of known declination.
In the following lists, the designation letter ("Des." column) is a reference assigned to the chronometer while it was on board ship and was used to identify the instrument in logged tables of chronometer readings during the voyage. It was a temporary designation with no relevance once the ship's mission was over.
A marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship's position by celestial navigation.It is used to determine longitude by comparing Greenwich Mean Time (GMT), and the time at the current location found from observations of celestial bodies.