Time Scales
Historical Julian dates were recorded relative to GMT or Ephemeris Time, but the International Astronomical Union now recommends that Julian Dates be specified in Terrestrial Time, and that when necessary to specify Julian Dates using a different time scale, that the time scale used be indicated when required, such as JD(UT1). The fraction of the day is found by converting the number of hours, minutes, and seconds after noon into the equivalent decimal fraction. Time intervals calculated from differences of Julian Dates specified in non-uniform time scales, such as Coordinated Universal Time (UTC), may need to be corrected for changes in time scales (e.g. leap seconds).
Read more about this topic: Julian Day
Famous quotes containing the words time and/or scales:
“Remember how often you have postponed minding your interest, and let slip those opportunities the gods have given you. It is now high time to consider what sort of world you are part of, and from what kind of governor of it you are descended; that you have a set period assigned you to act in, and unless you improve it to brighten and compose your thoughts, it will quickly run off with you, and be lost beyond recovery.”
—Marcus Aurelius Antoninus (121–180)
“In what camera do you taste
Poison, in what darkness set
Glittering scales and point
The tipping tongue?”
—Wallace Stevens (1879–1955)