Sun Position Calculator: Azimuth & Elevation

Computes where the sun stands in the sky for a latitude, longitude, date and clock time: its elevation above the horizon, its azimuth measured clockwise from true north, the zenith angle, declination, local hour angle and the equation of time. From those it gives the length and direction of the shadow cast by an object of the height you enter, the relative air mass (Kasten and Young, 1989) and an hour-by-hour table for the whole day, which is what you want for placing a solar panel, planning a photograph or checking whether a window gets direct sun. The solar coordinates follow Meeus's Astronomical Algorithms with the nutation and aberration corrections and a ΔT model, and agree with PyEphem to about 0.01° anywhere on Earth between 1900 and 2100; NREL's published SPA test case comes out within 0.006°. Refraction is added with Sæmundsson's formula for the pressure and temperature you give, which matters most near the horizon, where it lifts the sun by about half a degree; switch it off to see the airless geometric position. Refraction at very low elevations depends on the actual air layers, so a sunrise-grazing value can be off by a tenth of a degree or more whatever the model. The UTC offset is entered by hand, because daylight saving time is a local rule the tool cannot know for every place and year; use the button to take the current time and offset from your device.