Documentation / @interstellar-tools/constants / J2000_UTC

Variable: J2000_UTC

const J2000_UTC: Date;

Defined in: date.ts:36

J2000 epoch as a UTC timestamp for JavaScript usage.

J2000 is defined as JD 2451545.0 (TT), i.e. 2000-01-01 12:00:00 TT. At that epoch TT − UTC = 64.184 s, so the corresponding UTC instant is: 2000-01-01T11:58:55.816Z.

Example

// Milliseconds from UTC midnight to J2000 (UTC):
const deltaMs = +J2000_UTC - +EPOCH_2000_UTC_MIDNIGHT; // 43_135_816 ms

// If you need the TT-based Julian centuries since J2000:
//   T = (JD_TT - J2000_TT) / 36525
// Compute JD_TT from a UTC Date using your UTC→TT→JD pipeline, then use J2000_TT.