1 PRINT "From the May 1984 SKY & TELESCOPE, pp. 454-5."
2 PRINT
3 PRINT "This program converts a civil date to a Julian date.  It will work"
4 PRINT "with either the Gregorian or Julian calendar, and with either"
5 PRINT "positive or negative years."
6 PRINT
7 PRINT "INPUT :  Year (Y), month (M), day with fraction (D) (UT), Julian or"
8 PRINT "         Gregorian calendar."
9 PRINT
10 PRINT "OUTPUT:  Julian Day number, Julian Day fractional part."
11 PRINT
800 REM   CALENDAR --> JD
805 REM
810 INPUT "Y,M,D ";Y,M,D
815 INPUT "JC (0) OR GC (1) ";G
820 D1=INT(D): F=D-D1-.5
825 J=-INT(7*(INT((M+9)/12)+Y)/4)
830 IF G=0 THEN 850
835 S=SGN(M-9): A=ABS(M-9)
840 J1=INT(Y+S*INT(A/7))
845 J1=-INT((INT(J1/100)+1)*3/4)
850 J=J+INT(275*M/9)+D1+G*J1
855 J=J+1721027!+2*G+367*Y
860 IF F>=0 THEN 870
865 F=F+1: J=J-1
870 PRINT "J.D.: ";J;F
875 RUN"ASTRMENU.BAS"