Azimuth

For the Legacy of Kain character, see Azimuth the Planer.

For the band, see Azimuth (band). Azimuth was a Jazz trio active from 1977 to 2000 The ensemble was comprised of trumpeter Kenny Wheeler, vocalist Norma Winstone, and Winstone's husband

Azimuth (ˈæzɪməθ (help·info)) is a mathematical concept defined as the angle, usually measured in degrees (°), between a reference plane and a point. This article describes the unit of angle For other meanings see Degree. In Geometry, Topology and related branches of mathematics a spatial point describes a specific point within a given space that consists of neither Volume This concept is used in many practical applications including navigation, astronomy, mapping, mining and artillery. Navigation is the process of reading and controlling the movement of a craft or vehicle from one place to another Astrometry is the branch of Astronomy that relates to precise measurements and explanations of the positions and movements of Stars and other celestial bodies Artillery (from French artillerie) is a military Combat Arm which employs any apparātus machine The word azimuth is derived from the Arabic السمت ('as-sumūt') which means the ways, referring to the ways or directions a person faces.

1 Navigation
- 1.1 True north-based azimuths
2 Mapping
3 Astronomy
4 Other uses
5 Other systems
6 See also

Navigation

In navigation, the reference plane is typically true north and is considered 0° azimuth. noted by the Chinese Polymath Shen Kuo in the 11th century and possibly the egyptians over 6 millenia ago Moving clockwise, a point due east would have an azimuth of 90°, south 180°, and west 270°. A clockwise motion is one that proceeds 'like the Clock 's hands' from the top to the right then down and then to the left and back to the top Some navigation systems use south as the reference plane. However, any direction can serve as the plane of reference, as long as it is clearly defined for everyone using that system.

True north-based azimuths

From North
North	0° or 360°	South	180°
North-Northeast	22. 5°	South-Southwest	202. 5°
Northeast	45°	Southwest	225°
East-Northeast	67. 5°	West-Southwest	247. 5°
East	90°	West	270°
East-Southeast	112. 5°	West-Northwest	292. 5°
Southeast	135°	Northwest	315°
South-Southeast	157. 5°	North-Northwest	337. 5°

Mapping

There are a wide variety of azimuthal map projections. A map projection is any method of representing the Surface of a sphere or other shape on a plane. They all have the property that directions (the azimuths) from a central point are preserved. Some navigation systems use south as the reference plane like in the Philippine practice. However, any direction can serve as the plane of reference, as long as it is clearly defined for everyone using that system.

Astronomy

Azimuth is often, some consider incorrectly, referred to as a bearing. In Navigation, a bearing is the direction one object is from another object However, in modern astronomy azimuth is nearly always measured from the north. Astronomy (from the Greek words astron (ἄστρον "star" and nomos (νόμος "law" is the scientific study In former times, it was common to refer to azimuth from the south, as it was then zero at the same time the hour angle of a star was zero. In Astronomy, the hour angle is one of the coordinates used in the Equatorial coordinate system for describing the position of a point on the Celestial sphere A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth This assumes, however, that the star (upper) culminates in the south, which is only true for most stars in the Northern Hemisphere. In astronomy the culmination, at a given point of a Planet, Star, Constellation, etc Northern Hemisphere is the half of a Planet that is North of the Equator —the word hemisphere literally means 'half ball'

Other uses

Azimuth is used to determine headings or the direction in which to fly. In artillery, it is the direction of fire. Artillery (from French artillerie) is a military Combat Arm which employs any apparātus machine

Azimuth is also terms used in mining for a similar, but slightly different angle: azimuths and meridian angles are used to name any angle measured clockwise from any meridian. Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body

For tape and cassette tape decks, azimuth refers to the angle between the tape head(s) and tape. For magnetic tape drives, azimuth refers to the angle between the tape head(s)

Other systems

Declination

If instead of measuring from and along the horizon the angles are measured from and along the celestial equator, the angles are called declination and right ascension (hour angle). A tape drive, which is also known as a streamer, is a data storage device that reads and writes data stored on a magnetic tape. The celestial equator is a Great circle on the imaginary Celestial sphere, in the same plane as the Earth 's Equator. In Astronomy, declination (abbrev dec or δ) is one of the two coordinates of the Equatorial coordinate system, the other being either Right ascension (abbrev RA; symbol α) is the Astronomical term for one of the two Coordinates of a point on the Celestial sphere

Horizontal coordinate

In the horizontal coordinate system, used in celestial navigation and satellite dish installation, azimuth is one of the two coordinates. The horizontal coordinate system is a Celestial coordinate system that uses the observer's local Horizon as the fundamental plane. Celestial navigation, also known as astronavigation, is a Position fixing technique that was devised to help sailors cross the featureless oceans without having to A satellite dish is a type of Parabolic antenna that receives or transmits electromagnetic signals to and from another location typically a satellite In Mathematics and its applications a coordinate system is a system for assigning an n - Tuple of Numbers or scalars to each point The other is altitude, sometimes called elevation above the horizon. In Astronomy, a celestial coordinate system is a Coordinate system for mapping positions in the sky See also: Sat finder. A Sat finder is a satellite signal Meter used to accurately point satellite dishes at communications satellites in geostationary orbit

Polar coordinate

In three-dimensional polar coordinate systems, including cylindrical coordinates and spherical coordinates, the azimuth of a point is the angle between the positive x-axis and the projection of the vector onto the xy-plane (the component of the vector in the xy-plane). Coordinates are numbers which describe the location of points in a plane or in space The cylindrical coordinate system is a three-dimensional Coordinate system which essentially extends circular polar coordinates by adding a third coordinate (usually In Mathematics, the spherical coordinate system is a Coordinate system for representing geometric figures in three dimensions using three coordinates the radial In Geometry and Trigonometry, an angle (in full plane angle) is the figure formed by two rays sharing a common Endpoint, called In cylindrical coordinates, theta $θ$ is almost universally used to represent the azimuth in mathematical applications, whereas physical applications may denote the azimuth using the symbol phi, $φ$ . Theta (uppercase Θ, lowercase θ or ϑ; Θήτα is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth Phi (uppercase Φ, lowercase φ or ϕ) pronounced in modern Greek and as in English is the 21st letter of the Greek alphabet Although there are several conventions in spherical coordinates, the azimuth is usually denoted by either theta, $θ$ or phi, $φ$ .

Dictionary

-noun

An arc of the horizon intercepted between the meridian of the place and a vertical circle passing through the center of any object; as, the azimuth of a star; the azimuth or bearing of a line surveying.
The quadrant of an azimuth circle.

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