In addition, an epoch optionally prefixed by " J " and designated as a year with decimals ( 2000 + x ), where x is positive or negative and quoted to 1 or 2 decimal places, has come to mean a date that is an interval of x Julian years of 365.25 days away from the epoch J2000 = JD 2451545.0 ( TT ), still corresponding ( in spite of the use of the prefix " J " or word " Julian " ) to the Gregorian calendar date of 2000 Jan 1 at 12h TT ( about 64 seconds before noon UTC on the same calendar day ) . ( See also Julian year ( astronomy ) . ) Like the Besselian epoch, an arbitrary Julian epoch is therefore related to the Julian date by
