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authorTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
committerTaru Karttunen <taruti@taruti.net>2011-03-30 15:46:40 +0300
commite5888a1ffdae813d7575f5fb02275c6bb07e5199 (patch)
treed8d51eac403f07814b9e936eed0c9a79195e2450 /sys/src/cmd/astro/venus.c
Import sources from 2011-03-30 iso image
Diffstat (limited to 'sys/src/cmd/astro/venus.c')
-rwxr-xr-xsys/src/cmd/astro/venus.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/sys/src/cmd/astro/venus.c b/sys/src/cmd/astro/venus.c
new file mode 100755
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+++ b/sys/src/cmd/astro/venus.c
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+#include "astro.h"
+
+
+void
+venus(void)
+{
+ double pturbl, pturbb, pturbr;
+ double lograd;
+ double dele, enom, vnom, nd, sl;
+ double v0, t0, m0, j0, s0;
+ double lsun, elong, ci, dlong;
+
+/*
+ * here are the mean orbital elements
+ */
+
+ ecc = .00682069 - .00004774*capt + 0.091e-6*capt2;
+ incl = 3.393631 + .0010058*capt - 0.97e-6*capt2;
+ node = 75.779647 + .89985*capt + .00041*capt2;
+ argp = 130.163833 + 1.408036*capt - .0009763*capt2;
+ mrad = .7233316;
+ anom = 212.603219 + 1.6021301540*eday + .00128605*capt2;
+ motion = 1.6021687039;
+
+/*
+ * mean anomalies of perturbing planets
+ */
+
+ v0 = 212.60 + 1.602130154*eday;
+ t0 = 358.63 + .985608747*eday;
+ m0 = 319.74 + 0.524032490*eday;
+ j0 = 225.43 + .083090842*eday;
+ s0 = 175.8 + .033459258*eday;
+
+ v0 *= radian;
+ t0 *= radian;
+ m0 *= radian;
+ j0 *= radian;
+ s0 *= radian;
+
+ incl *= radian;
+ node *= radian;
+ argp *= radian;
+ anom = fmod(anom, 360.)*radian;
+
+/*
+ * computation of long period terms affecting the mean anomaly
+ */
+
+ anom +=
+ (2.761-0.022*capt)*radsec*sin(
+ 13.*t0 - 8.*v0 + 43.83*radian + 4.52*radian*capt)
+ + 0.268*radsec*cos(4.*m0 - 7.*t0 + 3.*v0)
+ + 0.019*radsec*sin(4.*m0 - 7.*t0 + 3.*v0)
+ - 0.208*radsec*sin(s0 + 1.4*radian*capt);
+
+/*
+ * computation of elliptic orbit
+ */
+
+ enom = anom + ecc*sin(anom);
+ do {
+ dele = (anom - enom + ecc * sin(enom)) /
+ (1 - ecc*cos(enom));
+ enom += dele;
+ } while(fabs(dele) > converge);
+ vnom = 2*atan2(sqrt((1+ecc)/(1-ecc))*sin(enom/2),
+ cos(enom/2));
+ rad = mrad*(1 - ecc*cos(enom));
+
+ lambda = vnom + argp;
+
+/*
+ * perturbations in longitude
+ */
+
+ icosadd(venfp, vencp);
+ pturbl = cosadd(4, v0, t0, m0, j0);
+ pturbl *= radsec;
+
+/*
+ * perturbations in latidude
+ */
+
+ pturbb = cosadd(3, v0, t0, j0);
+ pturbb *= radsec;
+
+/*
+ * perturbations in log radius vector
+ */
+
+ pturbr = cosadd(4, v0, t0, m0, j0);
+
+/*
+ * reduction to the ecliptic
+ */
+
+ lambda += pturbl;
+ nd = lambda - node;
+ lambda = node + atan2(sin(nd)*cos(incl),cos(nd));
+
+ sl = sin(incl)*sin(nd);
+ beta = atan2(sl, pyth(sl)) + pturbb;
+
+ lograd = pturbr*2.30258509;
+ rad *= 1 + lograd;
+
+
+ motion *= radian*mrad*mrad/(rad*rad);
+
+/*
+ * computation of magnitude
+ */
+
+ lsun = 99.696678 + 0.9856473354*eday;
+ lsun *= radian;
+ elong = lambda - lsun;
+ ci = (rad - cos(elong))/sqrt(1 + rad*rad - 2*rad*cos(elong));
+ dlong = atan2(pyth(ci), ci)/radian;
+ mag = -4 + .01322*dlong + .0000004247*dlong*dlong*dlong;
+
+ semi = 8.41;
+
+ helio();
+ geo();
+}