COMPUTE GAG_DATE

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COMPUTE GAG_DATE

            [SIC\]COMPUTE IntDate GAG_DATE "15-DEC-2035"
            [SIC\]COMPUTE StrDate GAG_DATE 4127

        GAG_DATE keyword converts a string date into a "radio Julian date"  (in-
        teger  value), or vice-versa. The kind of the output variable (resp. in-
        teger or character) rules the expected kind for  input  variable  (resp.
        character or integer). The output variable must be scalar and writeable,
        and the date string should be 11 characters at least.

        A "radio Julian date" (or "Jansky Julian date") starts as -2^15  on  the
        date of the first radio observation by Karl Jansky. It is thus the Modi-
        fied Julian date minus 60549. That choice was made to maximize the  time
        interval  over which radio astronomical data could be usefully stored in
        an integer*2, back when 2 bytes of header space per spectrum were a sig-
        nificant  consideration. This date has little meaning outside the rather
        sparse community of souls gathered around the CLASS program, however.