J
- Instance of
Overview
All data
8 statements · 0% with external sources · numbers in brackets are citations
- Date
- January 1, 2000
- Followed by
- unknown
On other databases
1 identifiers linking J2000.0 across the web's reference databases
8 statements · 0% with external sources · numbers in brackets are citations
1 identifiers linking J2000.0 across the web's reference databases
From Wikipedia, the free encyclopedia · Read full article · Text CC BY-SA 4.0
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit.