ref: 8417787f994891759273865919b34b5a2e6e8735
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; }