Sun Calculator

SunCalc (suncalc.net) is an online solar position calculator that computes the sun's position — azimuth, altitude, and direction of shadows — at any geographic location for any date and time. It visualizes sunrise, sunset, twilight periods, solar noon, and shadow direction on an interactive map.

For OSINT investigators, SunCalc is a precision geolocation tool used to verify or establish locations based on shadow analysis in photographs and video. When an image shows shadows cast by structures, trees, or people, the shadow direction encodes information about the sun's position at the time the image was taken. If the sun's position at the time and location matches the observed shadows, the proposed location and timestamp are corroborated.

Shadow analysis methodology: Identify a clear shadow in the target image. Measure the shadow's direction relative to compass bearing. Enter the proposed location, date, and time in SunCalc. Compare the computed shadow direction with the observed shadow. If they match, the location and time are consistent with the image. Significant discrepancies eliminate the candidate location or time.

This technique is widely used in open-source geolocation investigations of conflict imagery, to establish the authenticity of event documentation (confirming that a photograph claimed to be from a specific date and location is consistent with the solar position), and for image authentication in forensic contexts.

SunCalc also shows the golden hour and blue hour windows — the periods before and after sunrise/sunset with characteristic warm or cool lighting. Investigators can use lighting quality in images as a rough temporal indicator: strongly warm directional light suggests the image was taken within an hour of sunrise or sunset.

The moon phase and position calculator extension of SunCalc provides equivalent analysis for nighttime imagery, allowing investigators to verify claimed night image timestamps using moon position and phase.

Document the proposed location, date, time, calculated solar azimuth, and the match quality between calculated and observed shadows in geolocation analysis reports.