time coordinate
41Horizontal coordinate system — The horizontal coordinate system is a celestial coordinate system that uses the observer s local horizon as the fundamental plane. This conveniently divides the sky into the upper hemisphere that you can see, and the lower hemisphere that you… …
42Polar coordinate system — Points in the polar coordinate system with pole O and polar axis L. In green, the point with radial coordinate 3 and angular coordinate 60 …
43Cartesian coordinate system — Illustration of a Cartesian coordinate plane. Four points are marked and labeled with their coordinates: (2, 3) in green, (−3, 1) in red, (−1.5, −2.5) in blue, and the origin (0, 0) in purple. A Cartesian coordinate system specifies each point… …
44Geocentric Coordinate Time — (TCG) is a coordinate time standard intended to be used as the independent variable of time for all calculations pertaining to precession, nutation, the Moon, and artificial satellites of the Earth. It is equivalent to the proper time experienced …
45Barycentric Coordinate Time — (TCB) is a coordinate time standard intended to be used as the independent variable of time for all calculations pertaining to orbits of planets, asteroids, comets, and interplanetary spacecraft in the Solar system. It is equivalent to the proper …
46Terrestrial Time — (TT) is the modern astronomical standard for the passage of time on the surface of the Earth (for civil purposes, Coordinated Universal Time (UTC) is standard). Since time moves at different rates for observers in different locations (due to… …
47Celestial coordinate system — For other uses of Celestial , see Celestial (disambiguation). Orientation of Astronomical Coordinates Orientation of the galactic, ecliptic and equatorial coordinate systems, projected on the celestial sphere, showing the galactic equator (black) …
48Barycentric Dynamical Time — (TDB) was a time standard used to take account of time dilation when calculating orbits of planets, asteroids, comets and interplanetary spacecraft in the Solar system. It was based on a Dynamical time scale but was not well defined and not… …
49Gravitational time dilation — is the effect of time passing at different rates in regions of different gravitational potential; the higher the local distortion of spacetime due to gravity, the slower time passes. Albert Einstein originally predicted this effect in his theory… …
50Harmonic coordinate condition — The harmonic coordinate condition is one of several coordinate conditions in general relativity, which make it possible to solve the Einstein field equations. A coordinate system is said to satisfy the harmonic coordinate condition if each of the …
