Moonrise, Moonset & Moon Position

Finds when the Moon rises, crosses the meridian and sets on a given local day, and where it stands at the moment you choose: altitude, azimuth from true north, distance from you and from the centre of the Earth, the illuminated fraction and the phase name. The Moon's position comes from the lunar theory in Meeus's Astronomical Algorithms (chapter 47, the 120-term truncation of ELP-2000/82), with nutation, ΔT and the parallax for your place on the WGS 84 ellipsoid — the Moon is close enough that its direction shifts by up to a degree between the centre of the Earth and your location, which is why a naive calculation can be minutes out. Rise and set follow the convention the U.S. Naval Observatory uses: the upper limb touching the horizon with 34′ of standard refraction, for an observer at sea level with a flat horizon. Checked against PyEphem, the times agree to within about a second and the position to a few thousandths of a degree. Some days have no moonrise or no moonset at all, because the Moon rises about 50 minutes later each day and one event slips past midnight; at high latitudes the Moon can stay up or stay down for days, and the tool says which. Real horizons are not flat: hills, buildings, elevation and unusual refraction move the observed times by minutes, so treat the seconds as the model's precision, not a promise. The UTC offset is typed by hand because daylight-saving rules differ by place and year.