Day and night map
Where the Sun is up right now: the terminator and the subsolar point on a world map.
- Subsolar point
- Sublunar point
- Civil twilight
- Nautical twilight
- Astronomical twilight
- Night
About this tool
The map shows which part of the Earth is in daylight at the chosen instant. The subsolar point is the place where the Sun is exactly overhead: its latitude equals the Sun’s declination (between ±23.44° over the year) and its longitude follows the time of day, moving west by 15° per hour. The terminator, the line between day and night, is the great circle 90° away from that point.
Night does not fall all at once. Civil twilight lasts while the Sun is less than 6° below the horizon and there is still enough light for outdoor activities; nautical twilight goes down to 12°, when the horizon is still visible at sea; astronomical twilight ends at 18°, when the sky is finally fully dark. The four bands on the map correspond to these thresholds. The Moon’s marker shows the sublunar point, where it stands at the zenith.
Everything is computed by Explorer’s own astronomy library from Jean Meeus’s algorithms: the Sun’s position to a few hundredths of a degree, the Moon’s from a shortened series accurate to about 0.2° — good enough for a map, not for an eclipse. Use it to see who in the community can be observing right now, or to picture the season: at the solstices the terminator tilts to its maximum, at the equinoxes it runs through both poles.