About
Subsolar shows the place where the Sun is directly overhead at a selected time.
Calculation
The Sun's position is calculated using an astronomical approximation. The map marker shows the subsolar point; click the map to see the local azimuth and elevation. Results are approximate, with an estimated accuracy of about 0.02 degrees.
Time and map
Follow the current time or pause it and choose a date and time. The day-night boundary is shown as a line. Map tiles are provided by OpenStreetMap.
Messages and privacy
Contact messages are forwarded to the site administrator by email and their contents are not stored in the app database. To enforce sending limits, the server stores a keyed hash of the IP address, the time of the request, and the event type. Events older than 30 days are deleted when new contact requests are received. The form's one-time token expires after 15 minutes. Usage statistics record page views, map clicks without coordinates, and time-control actions. A random per-tab code groups those events; only its hash is stored, and usage events are deleted after 90 days.