xref: /plan9/sys/src/cmd/astro/sun.c (revision 3e12c5d1bb89fc02707907988834ef147769ddaf)
1 #include "astro.h"
2 
3 void
sun(void)4 sun(void)
5 {
6 	double mven, merth, mmars, mjup, msat;
7 	double dmoon, mmoon, gmoon;
8 	double pturbb, pturbl, pturbr, lograd;
9 
10 	ecc = .01675104 - 4.180e-5 * capt - 1.26e-7*capt2;
11 	incl = 0;
12 	node = 0;
13 	argp = 281.220833 + .0000470684*eday + .000453*capt2
14 		 + .000003*capt3;
15 	mrad = 1;
16 	anom = 358.475845 + .9856002670*eday - .000150*capt2
17 		 - .000003*capt3;
18 	motion = .9856473354;
19 
20 	dmoon = 350.737681+12.1907491914*eday-.001436*capt2;
21 	gmoon = 11.250889 + 13.2293504490*eday - .003212*capt2;
22 	mmoon = 296.104608 + 13.0649924465*eday + 9.192e-3*capt2;
23 	mven  = 212.448 + 1.602121635*eday;
24 	merth = 358.476 + 0.985600267*eday;
25 	mmars = 319.590 + .524024095*eday;
26 	mjup = 225.269 + .083082362*eday;
27 	msat  = 175.593 + .033450794*eday;
28 
29 	dmoon = fmod(dmoon, 360.)*radian;
30 	gmoon = fmod(gmoon, 360.)*radian;
31 	mmoon = fmod(mmoon, 360.)*radian;
32 	mven  *= radian;
33 	merth *= radian;
34 	mmars *= radian;
35 	mjup *= radian;
36 	msat  *= radian;
37 
38 	icosadd(sunfp, suncp);
39 	anom += cosadd(4, mmars, merth, mven, mjup)/3600.;
40 	anom += sinadd(5, mmars, merth, mven, mjup, .07884*capt)/3600.;
41 
42 	incl *= radian;
43 	node *= radian;
44 	argp *= radian;
45 	anom = fmod(anom, 360.)*radian;
46 
47 /*
48  *	computation of elliptic orbit
49  */
50 
51 	lambda = anom + argp;
52 
53 	pturbl = (6910.057 - 17.240*capt - 0.052*capt2)*sin(anom)
54 		 + (72.338 - 0.361*capt) * sin(2.*anom)
55 		 + (1.054 - 0.001*capt) * sin(3.*anom)
56 		 + 0.018 * sin(4.*anom);
57 
58 	lambda += pturbl*radsec;
59 
60 	beta = 0.;
61 
62 	lograd = (30.57e-6 - 0.15e-6*capt)
63 		 - (7274.12e-6 - 18.14e-6*capt - 0.05e-6*capt2)*cos(anom)
64 		 - (91.38e-6 - 0.46e-6*capt) * cos(2.*anom)
65 		 - (1.45e-6 - 0.01e-6*capt) * cos(3.*anom)
66 		 - 0.02e-6 * cos(4.*anom);
67 
68 	pturbl = cosadd(5, mmars, merth, mven, mjup, msat);
69 	pturbl += sinadd(3, dmoon, mmoon, merth) + .9;
70 	pturbl *= radsec;
71 
72 	pturbb =  cosadd(3, merth, mven, mjup);
73 	pturbb += sinadd(3, gmoon, mmoon, dmoon);
74 	pturbb *= radsec;
75 
76 	pturbr =  cosadd(5, mmars, merth, mven, mjup, msat);
77 	pturbr += cosadd(3, dmoon, mmoon, merth);
78 
79 	lambda += pturbl;
80 	if(lambda > pipi)
81 		lambda -= pipi;
82 
83 	beta += pturbb;
84 
85 	lograd = (lograd+pturbr) * 2.30258509;
86 	rad = 1 + lograd * (1 + lograd * (.5 + lograd/6));
87 
88 	motion *= radian*mrad*mrad/(rad*rad);
89 
90 	semi = 961.182;
91 	if(flags['o'])
92 		semi = 959.63;
93 	mag = -26.5;
94 }
95