9 * sets phi, eps, dphi, deps, obliq, gst, tobliq
12 double msun, mnom, noded, dmoon;
15 * nutation of the equinoxes is a wobble of the pole
16 * of the earths rotation whose magnitude is about
17 * 9 seconds of arc and whose period is about 18.6 years.
19 * it depends upon the pull of the sun and moon on the
20 * equatorial bulge of the earth.
22 * phi and eps are the two angles which specify the
23 * true pole with respect to the mean pole.
25 * all coeffieients are from Exp. Supp. pp.44-45
28 mnom = 296.104608 + 13.0649924465*eday + 9.192e-3*capt2
31 msun = 358.475833 + .9856002669*eday - .150e-3*capt2
34 noded = 11.250889 + 13.2293504490*eday - 3.211e-3*capt2
37 dmoon = 350.737486 + 12.1907491914*eday - 1.436e-3*capt2
40 node = 259.183275 - .0529539222*eday + 2.078e-3*capt2
54 icosadd(nutfp, nutcp);
55 phi = -(17.2327+.01737*capt)*sin(node);
56 phi += sinadd(4, node, noded, dmoon, msun);
58 eps = cosadd(4, node, noded, dmoon, msun);
65 dphi = sinadd(4, node, noded, mnom, dmoon);
67 deps = cosadd(3, node, noded, mnom);
69 phi = (phi+dphi)*radsec;
70 eps = (eps+deps)*radsec;
74 obliq = 23.452294 - .0130125*capt - 1.64e-6*capt2
79 gst = 99.690983 + 360.9856473354*eday + .000387*capt2;
81 gst = fmod(gst, 360.);
85 gst += phi*cos(obliq);