tmars.c - plan9port - [fork] Plan 9 from user space
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       ---
       tmars.c (1379B)
       ---
            1 #include "astro.h"
            2 
            3 void
            4 mars(void)
            5 {
            6         double pturbl, pturbb, pturbr;
            7         double lograd;
            8         double dele, enom, vnom, nd, sl;
            9         double lsun, elong, ci, dlong;
           10 
           11 
           12         ecc = .09331290 + .000092064*capt;
           13         incl = 1.850333 - 6.75e-4*capt;
           14         node = 48.786442 + .770992*capt;
           15         argp = 334.218203 + 1.840758*capt + 1.30e-4*capt2;
           16         mrad = 1.5236915;
           17         anom = 319.529425 + .5240207666*eday + 1.808e-4*capt2;
           18         motion = 0.5240711638;
           19 
           20 
           21         incl = incl*radian;
           22         node = node*radian;
           23         argp = argp*radian;
           24         anom = fmod(anom,360.)*radian;
           25 
           26         enom = anom + ecc*sin(anom);
           27         do {
           28                 dele = (anom - enom + ecc * sin(enom)) /
           29                         (1. - ecc*cos(enom));
           30                 enom += dele;
           31         } while(fabs(dele) > converge);
           32         vnom = 2.*atan2(sqrt((1.+ecc)/(1.-ecc))*sin(enom/2.),cos(enom/2.));
           33         rad = mrad*(1. - ecc*cos(enom));
           34 
           35         lambda = vnom + argp;
           36         pturbl = 0.;
           37         lambda = lambda + pturbl*radsec;
           38         pturbb = 0.;
           39         pturbr = 0.;
           40 
           41 /*
           42  *        reduce to the ecliptic
           43  */
           44 
           45         nd = lambda - node;
           46         lambda = node + atan2(sin(nd)*cos(incl),cos(nd));
           47 
           48         sl = sin(incl)*sin(nd) + pturbb*radsec;
           49         beta = atan2(sl, pyth(sl));
           50 
           51         lograd = pturbr*2.30258509;
           52         rad *= 1. + lograd;
           53 
           54 
           55         motion *= radian*mrad*mrad/(rad*rad);
           56         semi = 4.68;
           57 
           58         lsun = 99.696678 + 0.9856473354*eday;
           59         lsun *= radian;
           60         elong = lambda - lsun;
           61         ci = (rad - cos(elong))/sqrt(1. + rad*rad - 2.*rad*cos(elong));
           62         dlong = atan2(pyth(ci), ci)/radian;
           63         mag = -1.30 + .01486*dlong;
           64 
           65         helio();
           66         geo();
           67 }