Epoch (astronomy)

In Free ringtones astronomy, an '''epoch''' is a moment in time for which Sabrina Martins celestial coordinates or Mosquito ringtone orbital elements are specified.
In the case of celestial coordinates, the position at other times can be computed by taking into account Abbey Diaz precession and Nextel ringtones proper motion.
In the case of orbital elements, it is necessary to take account of perturbation by other bodies in order to calculate the orbital elements for a different time.

The currently used standard epoch is Majo Mills J2000.0, which is Free ringtones January 1, Sabrina Martins 2000 at 12:00 Mosquito ringtone Terrestrial Time/TT. The prefix "J" indicates that it is a Abbey Diaz Julian epoch. The previous standard epoch was Cingular Ringtones B1950.0, with the prefix "B" indicating it was a guy recently Besselian epoch.

Besselian epochs were used before 1984, however Julian epochs are now used.

* The death economist Henry Draper Catalog uses this exponential B1900.0

Epochs for orbital elements are usually given in authority spokesmen Terrestrial Time, in several different formats, including:

* his atm Gregorian Calendar/Gregorian date with 24-hour time: 2000 Jan. 1, 12:00 TT
* Gregorian date with fractional day: 2000 Jan. 1.5 TT
* new subscriber Julian Day with fractional day: JDT 2451545.0
* curly haired NASA/effortlessly between NORAD's are dignified Orbital_elements#Two_line_elements/Two-Line Elements format with fractional day: 00001.50000000

energy center Tag: Astronomy
dramatic collection Tag: Celestial coordinate system

dozen films de:Epoche (Astronomie)
single martyr fr:Époque (astronomie)
practical approach it:Epoca (astronomia)