Method & sources

Moon-free darkness means the Sun is at least 18° below the horizon and the Moon has completely set. Sunset comes earlier, before the sky becomes fully dark.

Positions, phase, and rise/set times are computed on your device with Astronomy Engine 2.1.19. Rise and set account for the apparent disc and standard atmospheric refraction. Twilight uses the geometric Sun at −18°, following U.S. Naval Observatory definitions.

Times are rounded to the nearest minute in the observing location’s time zone, including daylight saving. +1d means the following date. Each night runs from local noon to the next noon. Evening (↘) runs from dusk until moonrise; morning (↗) runs from moonset toward dawn. Continuous windows stay intact across midnight. A • marks a fully moon-free dark night. Actual elapsed durations include daylight-saving changes. Rounding can make the displayed parts differ from their total by a minute. Moon illumination is evaluated around the intervening midnight.

Calculations assume a level, unobstructed horizon and an observer at ground level at the entered elevation. Mountains, buildings, atmospheric conditions, clouds, and light pollution affect your observing conditions. Moon illustrations show phase with north up.

254 capital cities and government seats come from GeoNames, adapted under CC BY 4.0. City-centre coordinates and elevations are approximate; use custom coordinates for your actual observing spot. Where elevation is unavailable, sea level is shown as an estimate. See the data notes for coverage and additions.

The location picker uses Leaflet 1.9.4 and map tiles from OpenStreetMap contributors. Coordinate time zones are inferred locally with @photostructure/tz-lookup 11.7.0; the compressed boundaries can be approximate near borders and coastlines. The time zone can be set manually. See dependency sources and licences.