SUMMARY JULIAN DATE

From: Andre Paige <apaige_at_idulab.gov>
Date: Fri, 20 Sep 1996 11:01:08 -0400

I want to thank the following individual for showing me how to display
the
what I had thought to be the julian date. Little did I know that even
in school one does not learn the truth.

The answer for the UNIX system was: date +%j
Input from the field:

Woody Lee <fastest to respond with query and answer>
        date +%j

Richard Turner <little history lesson>
        <TRUE Julian date (i.e. numbers of days since noon on some day in 1857
or some year
                like that) >
Jon Reeves <true to form - found it there>
        <date +%j (Julian date within year -- consult date(1) man page for
other
                formatting options)>

Andrew Weston <yes>
        <Do you mean the date command: date +%j>

Lucio Chiappetti <Must have looked it up? or is a computer himself>
< If you mean the *TRUE* Julian Day Number, as defined by the
  International Astronomical Union, i.e. the elapsed days from 12 UT
  of 1 Jan 4713 B.C., you need the following subroutine :

C
C SUBROUTINE JAYDAY FROM MSSL XRAY PACKAGE
C
      SUBROUTINE JAYDY(JY,JM,JD,JNL)
C CALENDAR TO JD DATE
      INTEGER *4 JNL,ITEMP1
      MY=JY
      MM=JM
      IF(MM-2)11,11,12
11 MM=MM+9
      MY=MY-1
      GOTO13
12 MM=MM-3
13 CONTINUE
      ITEMP1=MY
      JNL=15078+(1461*ITEMP1)/4+(153*MM+2)/5+JD
      RETURN
      END
 
If you mean the sequence number of the day in the current year (but
*PLEASE*
*PLEASE* *PLEASE* do *NOT* call it "julian date" ! It has nothing to do
with
it !) you can do

 date +j
>

Once more I want to thank all those that responded.

Sincerely,

Andre' A.B. Paige
Received on Fri Sep 20 1996 - 17:27:59 NZST

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