Name

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      DAYCNV

Purpose

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      Converts Julian dates to Gregorian calendar dates

Calling Sequence

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      DAYCNV, XJD, YR, MN, DAY, HR

Inputs

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      XJD = Julian date, positive double precision scalar or vector

Outputs

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      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

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      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

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      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

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