ref: 61f4c085c402af665b436f6d010d61107551d8a3
dir: /sys/src/cmd/astro/sun.c/
#include "astro.h"
void
sun(void)
{
double mven, merth, mmars, mjup, msat;
double dmoon, mmoon, gmoon;
double pturbb, pturbl, pturbr, lograd;
ecc = .01675104 - 4.180e-5 * capt - 1.26e-7*capt2;
incl = 0;
node = 0;
argp = 281.220833 + .0000470684*eday + .000453*capt2
+ .000003*capt3;
mrad = 1;
anom = 358.475845 + .9856002670*eday - .000150*capt2
- .000003*capt3;
motion = .9856473354;
dmoon = 350.737681+12.1907491914*eday-.001436*capt2;
gmoon = 11.250889 + 13.2293504490*eday - .003212*capt2;
mmoon = 296.104608 + 13.0649924465*eday + 9.192e-3*capt2;
mven = 212.448 + 1.602121635*eday;
merth = 358.476 + 0.985600267*eday;
mmars = 319.590 + .524024095*eday;
mjup = 225.269 + .083082362*eday;
msat = 175.593 + .033450794*eday;
dmoon = fmod(dmoon, 360.)*radian;
gmoon = fmod(gmoon, 360.)*radian;
mmoon = fmod(mmoon, 360.)*radian;
mven *= radian;
merth *= radian;
mmars *= radian;
mjup *= radian;
msat *= radian;
icosadd(sunfp, suncp);
anom += cosadd(4, mmars, merth, mven, mjup)/3600.;
anom += sinadd(5, mmars, merth, mven, mjup, .07884*capt)/3600.;
incl *= radian;
node *= radian;
argp *= radian;
anom = fmod(anom, 360.)*radian;
/*
* computation of elliptic orbit
*/
lambda = anom + argp;
pturbl = (6910.057 - 17.240*capt - 0.052*capt2)*sin(anom)
+ (72.338 - 0.361*capt) * sin(2.*anom)
+ (1.054 - 0.001*capt) * sin(3.*anom)
+ 0.018 * sin(4.*anom);
lambda += pturbl*radsec;
beta = 0.;
lograd = (30.57e-6 - 0.15e-6*capt)
- (7274.12e-6 - 18.14e-6*capt - 0.05e-6*capt2)*cos(anom)
- (91.38e-6 - 0.46e-6*capt) * cos(2.*anom)
- (1.45e-6 - 0.01e-6*capt) * cos(3.*anom)
- 0.02e-6 * cos(4.*anom);
pturbl = cosadd(5, mmars, merth, mven, mjup, msat);
pturbl += sinadd(3, dmoon, mmoon, merth) + .9;
pturbl *= radsec;
pturbb = cosadd(3, merth, mven, mjup);
pturbb += sinadd(3, gmoon, mmoon, dmoon);
pturbb *= radsec;
pturbr = cosadd(5, mmars, merth, mven, mjup, msat);
pturbr += cosadd(3, dmoon, mmoon, merth);
lambda += pturbl;
if(lambda > pipi)
lambda -= pipi;
beta += pturbb;
lograd = (lograd+pturbr) * 2.30258509;
rad = 1 + lograd * (1 + lograd * (.5 + lograd/6));
motion *= radian*mrad*mrad/(rad*rad);
semi = 961.182;
if(flags['o'])
semi = 959.63;
mag = -26.5;
}