DATETIME /FROM

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DATETIME /FROM

            [SIC\]DATETIME /FROM NOW
            [SIC\]DATETIME /FROM Val1 Form1 ... ValN FormN

        The option /FROM is used to define a single and non-ambiguous date-time.
        The  date-time  is  fully specified as the combination of a year, month,
        day, hour, minute, and seconds. They can be described with the following
        pairs:
          Iye YEAR (integer, default 1970)
          Imo MONTH (integer, default 1)
          Ida DAY (integer, default 1)
          Iho HOUR (integer, default 0)
          Imi MINUTE (integer, default 0)
          Nse SECONDS (real, default 0.0)

        The  pairs  can be combined in any order, but each field must be defined
        once at most. If a field is not specified, its default  value  is  used.
        The  day,  hour,  minute,  and  seconds fields can go beyond their usual
        ranges: the resulting date-time is shifted accordingly. For example:
          DATETIME /FROM 2015 YEAR                 ! 2015-01-01 00:00:00.000
          DATETIME /FROM 2015 YEAR 11 MONTH 16 DAY ! 2015-11-16 00:00:00.000
          DATETIME /FROM 2015 YEAR 100 DAY         ! 100-th day of year 2015

        The keyword NOW can be used alone to specify the current UTC  date-time.
        The  values  PREVIOUS  or NEXT can also be used for each field: they re-
        solve as the previous or next quantity with respect to the  current  UTC
        date-time.  These  syntaxes define all the fields at once, i.e. they can
        not be combined with other pairs of values. For example:
          DATETIME /FROM NOW           ! Now (UTC)
          DATETIME /FROM PREVIOUS DAY  ! Yesterday, same time
          DATETIME /FROM NEXT HOUR     ! Today or tomorrow, in 1 hour from now

        The option /FROM also recognizes specific date and/or time formats:
          JULIAN       Julian date with fractional day (e.g. 2457343.227256944)
          MJD          Modified Julian Date (e.g. 57342.72725694445)
          ISO          ISO date (e.g. 2015-11-16T17:27:15.000)
          GAG_DATE     GAG date integer format (e.g. -3207)
          YYYYMMDD     date with all numbers (e.g. 20151116)
          DD-MMM-YYYY  date where MMM is the month in letters (e.g. 16-NOV-2015)
          RADIAN       time of day in radians, usually betwen 0 and 2*pi
          SEXAGESIMAL  time of day using sexagesimal notation (e.g. 17:27:15.000)

        JULIAN, MJD and ISO define the 6 date and time fields: they can  not  be
        combined  with anything else. GAG_DATE, YYYYMMDD, and DD-MMM-YYYY define
        the date: they can be combined with a time specifier. RADIAN  and  SEXA-
        GESIMAL define the time: they can be combined with a date specifier. For
        example:
          DATETIME /FROM 2015-11-16T17:27:15.000 ISO
          DATETIME /FROM 57342.72725694445 MJD
          DATETIME /FROM -3207 GAG_DATE 4.569490147 RADIAN

        The inputs can be either explicit scalar values,  scalar  variables,  or
        array  variables.  They  can be mixed as long as arrays have equal size.
        For example
          DATETIME /FROM "16-NOV-2015" DD-MMM-YYYY ArrayVar RADIAN
        results in an array specification, where all the specified values  share
        the same date but each time is taken in ArrayVar.