"Originally used for any instrument used for observing stars; afterwards used for an instrument for measurement of altitute; replaced, in modern times, by the quadrant." — Williams, 1889

Astrolabe

"Originally used for any instrument used for observing stars; afterwards used for an instrument for…

"The horizontal angular distance between two meridians. <em>Magnetic A.</em> the horizontal angular distance of the magnetic from the geographical meridian. <em>A. compass</em>; a variety of ship's compass." &mdash; Williams, 1889

Azimuth

"The horizontal angular distance between two meridians. Magnetic A. the horizontal angular…

A pilot's cockpit from a propeller aeroplane, or airplane. The diagram illustrates the different parts of the cockpit used to control the plane. The cockpit contains gauges; watch; joystick controlling ailerons and elevators; and wires to adjust wings.

Aeroplane Cockpit

A pilot's cockpit from a propeller aeroplane, or airplane. The diagram illustrates the different parts…

A magnetic compass.

Compass

A magnetic compass.

A tool to know your direction.

Compass

A tool to know your direction.

"Compass, Mariner's, is the name given to the instrument by which sailors are enabled to steer their course on the ocean out of sight of land, and when neither sun nor stars are visible. the ancients, to whom it was unknown, could seldom venture to lose sight of the coast. The direct power of the magnet seems to have been unknown in Europe till late in the 12th century." &mdash; Chambers' Encyclopedia, 1875

Compass

"Compass, Mariner's, is the name given to the instrument by which sailors are enabled to steer their…

Compass card, part of ship's compass.

Compass Card

Compass card, part of ship's compass.

"It has four cardinal points, N, E, S, and W marked, as well as a circle graduated in degrees from sero to 360 degrees, clockwise around the circle." &mdash; Moss, 1914

Box compass

"It has four cardinal points, N, E, S, and W marked, as well as a circle graduated in degrees from sero…

Diagram of a ship's compass.

Compass, Ship's

Diagram of a ship's compass.

An illustration of the plane flying over land from point A to B by flying the plane with the direction of the plane. Then, flying to point D by creating a diagonal line at 100 mph onto destination point B.

Aeroplane Flying Over Plane

An illustration of the plane flying over land from point A to B by flying the plane with the direction…

A gimbals is a contrivance designed to keep a marine compass, chronometer, lamp, or other instrument in the horizontal position on board ship, notwithstanding the rolling and pitching of the vessel. The instrument is suspended in the diametral axis of a ring, which is again suspended in the diametral axis of another ring, the two axes being at right angles to one another.

Gimbals

A gimbals is a contrivance designed to keep a marine compass, chronometer, lamp, or other instrument…

A gimbals is a contrivance designed to keep a marine compass, chronometer, lamp, or other instrument in the horizontal position on board ship, notwithstanding the rolling and pitching of the vessel. The instrument is suspended in the diametral axis of a ring, which is again suspended in the diametral axis of another ring, the two axes being at right angles to one another.

This illustration shows a diagram of a gimbals, showing the angle of the ship (A), the perpendicular axes of the rings, and the compass suspended horizontally in the gimbals (B).

Gimbals (Diagram)

A gimbals is a contrivance designed to keep a marine compass, chronometer, lamp, or other instrument…

A gimbals is a contrivance designed to keep a marine compass, chronometer, lamp, or other instrument in the horizontal position on board ship, notwithstanding the rolling and pitching of the vessel. The instrument is suspended in the diametral axis of a ring, which is again suspended in the diametral axis of another ring, the two axes being at right angles to one another.
This illustration shows a gimbal joint.

Gimbals (Joint)

A gimbals is a contrivance designed to keep a marine compass, chronometer, lamp, or other instrument…

An illustration with multiple instruments used for navigation. These items include a globe, compass, map and books.

Globe

An illustration with multiple instruments used for navigation. These items include a globe, compass,…

"The sextant, an instrument of reflection used by navigators for measuring the altitudes of heavenly bodies."&mdash;Finley, 1917

Sextant

"The sextant, an instrument of reflection used by navigators for measuring the altitudes of heavenly…

"Sextant. An important instrument of navigation and surveying, for measuring the angular distance of two stars or other objects, or the altitude of a star above the horizon..." a, handle; b, c, mirrors; d, ring; e, telescope; f, arm; g, reading-lens; h, arc; i, screw; j, tangent screw. -Whitney, 1911

Sextant

"Sextant. An important instrument of navigation and surveying, for measuring the angular distance of…

"A number of rings arranged round a centre, so as to represent a sphere; used to illustrate the relative positions of the ecliptic, equator, etc., of the celestial sphere." &mdash; Williams, 1889

Armillary sphere

"A number of rings arranged round a centre, so as to represent a sphere; used to illustrate the relative…

The navigation symbol is found in front of the Tuileries a royal palace in Paris, France.

Navigation Symbol

The navigation symbol is found in front of the Tuileries a royal palace in Paris, France.

"The position of the true meridian may be found as follows: Point the hour hand of a watch towards the sun; the line joining the pivot and the point midway between the hour hand and XIII on the dial will point towards the south; that is to say if the observer stands so as to face the sun and the XII on the dial, he will be looking south. To point the hour hand exactly at the sun, stick a pin and bring the hour hand into the shadow. At night a line drawn toward the north star from the observer's position is approximately a true meridian." &mdash; Moss, 1914

True meridian

"The position of the true meridian may be found as follows: Point the hour hand of a watch towards the…