Search results
Results from the WOW.Com Content Network
These differ in their choice of fundamental plane, which divides the celestial sphere into two equal hemispheres along a great circle. Rectangular coordinates, in appropriate units, have the same fundamental (x, y) plane and primary (x-axis) direction, such as an axis of rotation. Each coordinate system is named after its choice of fundamental ...
In astronomy, the altitude in the horizontal coordinate system and the zenith angle are complementary angles, with the horizon perpendicular to the zenith. The astronomical meridian is also determined by the zenith, and is defined as a circle on the celestial sphere that passes through the zenith, nadir, and the celestial poles.
ACV – (celestial object) Alpha Canes Venatici, a class of rotating variable stars with strong magnetic fields named after Alpha Canum Venaticorum (Cor Caroli), the archetype for the class; ACYG – (celestial object) Alpha CYGni, a class of rotating variable stars named after Alpha Cygni (Deneb), the archetype for the class
The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental plane to define two angles of a spherical coordinate system: altitude and azimuth. Therefore, the horizontal coordinate system is sometimes called the az/el system, [1] the alt/az system, or the alt-azimuth system, among
For a location not on this axis, there is a unique meridian plane in this axial-pencil through that location. The intersection of this plane with Earth's surface defines two geographical meridians (either one east and one west of the prime meridian , or else the prime meridian itself and its anti-meridian), and the intersection of the plane ...
In other words, the prime vertical is the vertical circle perpendicular to the meridian, and passes through the east and west points, zenith, and nadir of any place. [2] A heavenly body is in or on the prime vertical when it bears true east or true west—when it is at right angles to the meridian.
It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the sun’s rays and a horizontal plane. [1] [2] At solar noon, the zenith angle is at a minimum and is equal to latitude minus solar declination angle. This is the basis by which ancient mariners navigated the oceans. [3]
These choices determine a reference plane that is typically defined as containing the point of origin and the x– and y–axes, either of which may be designated as the azimuth reference direction. The reference plane is perpendicular (orthogonal) to the zenith direction, and typically is designated "horizontal" to the zenith direction's ...