“Julian epoch”的概念、定义、翻译、参考文献-科学参考

Julian epoch

Astronomy

A method of specifying the date as a year with a decimal part, as for example in 1995.5. The unit is the Julian year of 365.25 days and the time-scale used is Barycentric Dynamical Time (TDB). It is often convenient to use the standard epoch, J2000.0, for example, in star catalogues. The prefix ‘J’ is added to distinguish this epoch from the more complicated Besselian epoch used prior to 1984. The standard epoch is defined as
$J 2000.0 = 2000 January 1.5 = 2000 January 1 12 h TDB$
The date for other epochs can be calculated from this. For example, J1999.0 is exactly 365.25 days earlier, that is, 1999 January 1.25.

单词	Julian epoch
释义	Julian epoch Astronomy A method of specifying the date as a year with a decimal part, as for example in 1995.5. The unit is the Julian year of 365.25 days and the time-scale used is Barycentric Dynamical Time (TDB). It is often convenient to use the standard epoch, J2000.0, for example, in star catalogues. The prefix ‘J’ is added to distinguish this epoch from the more complicated Besselian epoch used prior to 1984. The standard epoch is defined as $J 2000.0 = 2000 January 1.5 = 2000 January 1 12 h TDB$ The date for other epochs can be calculated from this. For example, J1999.0 is exactly 365.25 days earlier, that is, 1999 January 1.25.
随便看	FDNR FD protein FDR FDSN FE Feammox fear fear, geographies of feasibility study feasible feasible generalized least squares estimator feasible region feasible set feasible solution feather angle feathering feather ore feathers feature feature detection feature matching feature modelling Fechner, Gustav Theodor (1801–87) fecundity fed batch bioreactor