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DAYCNV

DAYCNV

Name


      DAYCNV

Purpose


      Converts Julian dates to Gregorian calendar dates

Explanation


      Duplicates the functionality of the intrinsic JUL2GREG procedure
      which was introduced in V8.2.1

Calling Sequence


      DAYCNV, XJD, YR, MN, DAY, HR

Inputs


      XJD = Julian date, positive double precision scalar or vector

Outputs


      YR = Year (Integer)
      MN = Month (Integer)
      DAY = Day (Integer)
      HR = Hours and fractional hours (Real). If XJD is a vector,
              then YR,MN,DAY and HR will be vectors of the same length.

Example


      IDL> DAYCNV, 2440000.D, yr, mn, day, hr
      yields yr = 1968, mn =5, day = 23, hr =12.
  WARNING:
      Be sure that the Julian date is specified as double precision to
      maintain accuracy at the fractional hour level.

Method


      Uses the algorithm of Fliegel and Van Flandern (1968) as reported in
      the "Explanatory Supplement to the Astronomical Almanac" (1992), p. 604
      Works for all Gregorian calendar dates with XJD > 0, i.e., dates after
      -4713 November 23.

Revision History


      Converted to IDL from Yeoman's Comet Ephemeris Generator,
      B. Pfarr, STX, 6/16/88
      Converted to IDL V5.0 W. Landsman September 1997



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