SCIENCE · FREE TOOL
Sun & shadow planner
See sun direction and a simple object’s shadow through the day.
Example coordinates are approximate city centers. Time-zone rules come from your browser. Use UTC for an unambiguous instant.
See the preview ↓Choose a sample or enter your settings to begin.
Data & measurements
Scroll sideways to see every column. You can also focus the table and use the arrow keys.
Follow the light, with the assumptions visible.
The compass uses true north, with azimuth measured clockwise. The shadow points opposite the sun. Its length is height ÷ tan(geometric sun altitude), on flat horizontal ground with an upright object. Below the geometric horizon, no direct-sun shadow is drawn. Close to the horizon, small altitude errors produce large shadow-length changes; the diagram caps its display and reports the calculated length separately.
Calculations use Julian centuries and the solar longitude, declination and equation-of-time method documented by NOAA’s solar calculation reference. NOAA’s legacy calculator is no longer maintained. This implementation is an approximate planning illustration, not a precise astronomical ephemeris. It omits observer elevation, atmospheric refraction, terrain, buildings, cloud cover and magnetic compass declination. Dates: 2000–2099; latitude ±89.9°. Compass direction is undefined when the sun is directly overhead.
The date and clock time are interpreted in the chosen IANA time zone, including the browser’s daylight-saving rules. Nonexistent or repeated local times during a clock change are rejected; choose UTC to specify the intended instant. Changing coordinates does not infer a time zone—set it explicitly. The day trace samples local times every 30 minutes, skipping ambiguous/nonexistent times. Its table is a sampled geometric altitude trace, not an exact sunrise/sunset schedule. Polar day/night may have no horizon crossings. This is not a solar installation, navigation, legal boundary or eye-safety tool; never look directly at the sun.