Julian Day(valid from 1900/3/1 to 2100/2/28) Julian day: 86400 s, Julian year: 365.25 d, Julian Century: 36525 d double JulianDay (int date, int month, int year, double UT) { if (month<=2) {month=month+12; year=year-1;} } Calculation of Lunar ecliptic coordinates can be found in: Montenbruck, Oliver / Pfleger, Thomas: Astronomie mit dem Personal Computer; mit CD-ROM, Springer Berlin, 4. Aufl. 2004, ISBN 3-540-21204-3 Montenbruck, Oliver / Pfleger, Thomas: Astronomy on the Personal Computer. with CD-ROM; Springer Berlin, 4th ed. 2004, ISBN 3-540-67221-4 Meeus, Jean: Astronomical Algorithms Willmann-Bell; Hardcover (1st ed. 1991), ISBN: 0943396352 Willmann-Bell; Hardcover (2nd ed. 1998), ISBN: 0943396611 Meeus, Jean: Astronomical Formulae for Calculators; Willmann-Bell; Softcover, ISBN: 0943396220 Convert ecliptic latitude B and longitude L to right ascension RA and declination delta obliquity of ecliptic: Compute sidereal time at Greenwich (according to: Jean Meeus: Astronomical Algorithms) T = (JD - 2451545.0 ) / 36525; Convert (tau,delta) to horizon coordinates of the observer (altitude h, azimuth az) sin(h) = sin(beta )*sin(delta) + cos(beta)*cos(delta)*cos(tau) Compute the parallax p in altitude: horParal = 8.794 / (moonDistance/149.59787E6); // horizontal parallax (arcseconds), Meeus S. 263 |