1 #include "astro.h"
2
3
4 void
venus(void)5 venus(void)
6 {
7 double pturbl, pturbb, pturbr;
8 double lograd;
9 double dele, enom, vnom, nd, sl;
10 double v0, t0, m0, j0, s0;
11 double lsun, elong, ci, dlong;
12
13 /*
14 * here are the mean orbital elements
15 */
16
17 ecc = .00682069 - .00004774*capt + 0.091e-6*capt2;
18 incl = 3.393631 + .0010058*capt - 0.97e-6*capt2;
19 node = 75.779647 + .89985*capt + .00041*capt2;
20 argp = 130.163833 + 1.408036*capt - .0009763*capt2;
21 mrad = .7233316;
22 anom = 212.603219 + 1.6021301540*eday + .00128605*capt2;
23 motion = 1.6021687039;
24
25 /*
26 * mean anomalies of perturbing planets
27 */
28
29 v0 = 212.60 + 1.602130154*eday;
30 t0 = 358.63 + .985608747*eday;
31 m0 = 319.74 + 0.524032490*eday;
32 j0 = 225.43 + .083090842*eday;
33 s0 = 175.8 + .033459258*eday;
34
35 v0 *= radian;
36 t0 *= radian;
37 m0 *= radian;
38 j0 *= radian;
39 s0 *= radian;
40
41 incl *= radian;
42 node *= radian;
43 argp *= radian;
44 anom = fmod(anom, 360.)*radian;
45
46 /*
47 * computation of long period terms affecting the mean anomaly
48 */
49
50 anom +=
51 (2.761-0.022*capt)*radsec*sin(
52 13.*t0 - 8.*v0 + 43.83*radian + 4.52*radian*capt)
53 + 0.268*radsec*cos(4.*m0 - 7.*t0 + 3.*v0)
54 + 0.019*radsec*sin(4.*m0 - 7.*t0 + 3.*v0)
55 - 0.208*radsec*sin(s0 + 1.4*radian*capt);
56
57 /*
58 * computation of elliptic orbit
59 */
60
61 enom = anom + ecc*sin(anom);
62 do {
63 dele = (anom - enom + ecc * sin(enom)) /
64 (1 - ecc*cos(enom));
65 enom += dele;
66 } while(fabs(dele) > converge);
67 vnom = 2*atan2(sqrt((1+ecc)/(1-ecc))*sin(enom/2),
68 cos(enom/2));
69 rad = mrad*(1 - ecc*cos(enom));
70
71 lambda = vnom + argp;
72
73 /*
74 * perturbations in longitude
75 */
76
77 icosadd(venfp, vencp);
78 pturbl = cosadd(4, v0, t0, m0, j0);
79 pturbl *= radsec;
80
81 /*
82 * perturbations in latidude
83 */
84
85 pturbb = cosadd(3, v0, t0, j0);
86 pturbb *= radsec;
87
88 /*
89 * perturbations in log radius vector
90 */
91
92 pturbr = cosadd(4, v0, t0, m0, j0);
93
94 /*
95 * reduction to the ecliptic
96 */
97
98 lambda += pturbl;
99 nd = lambda - node;
100 lambda = node + atan2(sin(nd)*cos(incl),cos(nd));
101
102 sl = sin(incl)*sin(nd);
103 beta = atan2(sl, pyth(sl)) + pturbb;
104
105 lograd = pturbr*2.30258509;
106 rad *= 1 + lograd;
107
108
109 motion *= radian*mrad*mrad/(rad*rad);
110
111 /*
112 * computation of magnitude
113 */
114
115 lsun = 99.696678 + 0.9856473354*eday;
116 lsun *= radian;
117 elong = lambda - lsun;
118 ci = (rad - cos(elong))/sqrt(1 + rad*rad - 2*rad*cos(elong));
119 dlong = atan2(pyth(ci), ci)/radian;
120 mag = -4 + .01322*dlong + .0000004247*dlong*dlong*dlong;
121
122 semi = 8.41;
123
124 helio();
125 geo();
126 }
127