Search results
Results From The WOW.Com Content Network
Heliographic coordinate systems are used to identify locations on the Sun's surface. The two most commonly used systems are the Stonyhurst and Carrington systems. They both define latitude as the angular distance from the solar equator, but differ in how they define longitude. In Stonyhurst coordinates, the longitude is fixed for an observer on ...
The equatorial describes the sky as seen from the Solar System, and modern star maps almost exclusively use equatorial coordinates. The equatorial system is the normal coordinate system for most professional and many amateur astronomers having an equatorial mount that follows the movement of the sky during the night.
The position of the Sun in the sky is a function of both the time and the geographic location of observation on Earth 's surface. As Earth orbits the Sun over the course of a year, the Sun appears to move with respect to the fixed stars on the celestial sphere, along a circular path called the ecliptic. Earth's rotation about its axis causes ...
In astronomy, the ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions, orbits, and pole orientations [1] of Solar System objects. Because most planets (except Mercury) and many small Solar System bodies have orbits with only slight inclinations to the ecliptic, using it as the ...
A right-handed convention, specifying a y axis 90° to the east in the fundamental plane and a z axis along Earth 's north polar axis. This frame is similar to the ξ, η, ζ frame above, except that the origin is removed to the centre of the Sun. It is commonly used in planetary orbit calculation.
The "width" of the figure is due to the equation of time, and its angular extent is the difference between the greatest positive and negative deviations of local solar time from local mean time when this time-difference is related to angle at the rate of 15° per hour, i.e., 360° in 24 h. This width of the analemma is approximately 7.7°, so ...
Lunar node. The lunar nodes are the two points where the Moon's orbital path crosses the ecliptic, the Sun's apparent yearly path on the celestial sphere. A lunar node is either of the two orbital nodes of the Moon, that is, the two points at which the orbit of the Moon intersects the ecliptic. The ascending (or north) node is where the Moon ...
Constructed with input data under the form of time series of station positions and Earth Orientation Parameters. [5] This version introduces extra parameters to describe the year-periodic motion of the stations: A (amplitude) and φ (phase) per-axis. This sort of seasonal variation has an amplitude of around 1 cm and is attributed to non-tidal ...