10 REM  this program is to track the sun from 10 minutes
20 REM  to 10 minutes starting at a given time/date       
30 REM constants
        pi = 3.14159265359#
        unitastro = 1.496E+08
35 REM latitude and longitude of my home         
	latitude = 44.83
	latitude = latitude* pi / 180
        longitude = -0.56
50 REM input page
        CLS
        PRINT "***************************************************"
        PRINT "*                                                 *"
        PRINT "*                    PROGRAMM                     *"
        PRINT "*                  TRACK THE SUN                  *"
        PRINT "*                                                 *"
        PRINT "*             from  10 MIN to 10 MIN              *"
        PRINT "***************************************************"
        PRINT "                                                   "
60 REM      input date
        INPUT " DATE of Beginning (JJ MM AAAA) :"; jour, mois, annee
        INPUT "TIME  UTC (HH MM)  :"; heure, minutes
70 REM  calculation of the number of days since 1/1/1900
150     h8 = (heure + minutes / 60) / 24
        j = jour + h8
        n = annee * 365 + 31 * (mois - 1) + j
        IF mois > 2 GOTO 160
        annee = annee - 1
160     n = n + INT(annee / 4) - INT(annee / 100) + INT(annee / 400)
        IF mois < 2 GOTO 190
        n = n - INT((mois - 1) * .4 + 2.7)
190 REM nj=number of days since  1/1/1901
        nj = n - 694325
        PRINT "number of daysa since 1/1/1901  :", nj
210     REM position of sun
        l0 = 4.8689
        l1 = .0172027914#
        p0 = 4.9085
        p1 = 8.1856E-07
        e = .01675104#
        k = 7
        a = 1.00000023#
        p = p0 + p1 * nj
        l2 = l0 + l1 * nj
        m = l2 - p
        m2 = m
220 REM equation of kepler
        u = m
        FOR kk = 0 TO k
        u = m + e * SIN(u)
        NEXT kk
        v = 2 * ATN(TAN(u / 2) * SQR((1 + e) / (1 - e)))
REM r=radius vector of sun  
        r = a * (1 - e * COS(u))
        PRINT "raduis vector of sun :", r
        PRINT "that is ", r * unitastro, "; km'"
        l = v + p
        xs = r * COS(l)
        ys = r * SIN(l)
        ld = l * 180 / pi
        ld = (ld / 360 - INT(ld / 360)) * 360
        IF ld < 0 THEN ld = ld + 360
REM ld=longitude of sun        
        ld = INT(ld * 10 + .5) / 10
        PRINT "longitude du soleil      :", ld
REM sideral time
        rd = 1.7273 + .0172027914# * nj + h8 * 2 * pi - longitude * pi / 180
        rd = (rd / 2 / pi - INT(rd / 2 / pi)) * 2 * pi
        IF rd < 0 THEN rd = rd + 2 * pi
        ts = rd
REM right ascention and  declinaison
        b = 0
        ep = .40927971#
        sd = COS(ep) * SIN(b) + SIN(ep) * COS(b) * SIN(l)
REM de=declinaison      
        de = ATN(sd / SQR(1 - sd * sd))
        sr = -SIN(ep) * SIN(b) + COS(ep) * COS(b) * SIN(l)
        rd = ATN(sr / COS(b) / COS(l))
        IF COS(b) * COS(l) < 0 THEN rd = rd + pi
        IF rd < 0 THEN rd = rd + (2 * pi)
REM ar=right asc  
        ar = rd
        h = INT(rd / pi * 12)
        mm = INT((rd - h * pi / 12) * 720 / pi)
        s = INT((rd - h * pi / 12 - m * pi / 720) * 43200 / pi)
        PRINT "right asc        :", h, mm, s
        PRINT "declinaison              :", INT(de * 18000 / pi + .5) / 100
REM  azimut elevation
        anghor = ts - ar
        cosdiszen = SIN(latitude) * SIN(de) + COS(latitude) * COS(de) * COS(anghor)
        elev = ATN(cosdiszen / SQR(-cosdiszen * cosdiszen + 1))
        elev = elev * 180 / pi
        ass = COS(de) * SIN(anghor)
        ac = (-COS(latitude) * SIN(de) + SIN(latitude) * COS(de) * COS(anghor) / COS(elev))
        azim = ATN(ass / ac)
        IF ac < 0 THEN azim = azim + pi
        azim = azim * 180 / pi
        azim = (azim / 360 - INT(azim / 360)) * 360
        IF azim < 0 THEN azim = azim + 360
        PRINT "azimut    :", azim
        PRINT "elevation :", elev
REM loop
        minutes = minutes + 10
        IF minutes > 60 THEN heure = heure + 1
        IF minutes > 60 THEN minutes = minutes - 60
        IF heure > 20 GOTO 300
        PRINT "***********************************************************"
        PRINT "                                                           "
        GOTO 150
300 PRINT "end of day"
400 END