How it works
Pick a city or use your location, then choose a date. The tool works out when the Sun sets and when each stage of twilight ends. Astronomical darkness begins when the Sun is 18° below the horizon; that is when faint galaxies and the Milky Way are at their best.
For the planets, it checks the sky every 10 minutes between sunset and sunrise, once the Sun is at least 6° below the horizon. A planet counts as visible if it climbs more than 5° above the horizon. You will see the time window, the moment it stands highest, its direction and its brightness.
Brightness uses the magnitude scale: the lower the number, the brighter the object. Venus and Jupiter are usually brighter than any star. Uranus and Neptune need binoculars or a telescope.
Times are estimates for a flat, open horizon. Hills, buildings and haze near the horizon can hide a low planet for longer.
Everything is calculated in your browser. Your location is used only on this page and is never sent to us. Sky positions are calculated with Astronomy Engine (Don Cross, MIT license).
How to find and see the planetsSteady points of light along the ecliptic: how to spot each planet and what to expect.
Moon phasesWhy the Moon changes shape over a month, and which phases are best for observing.
How to watch a meteor showerWhen to go out, where to look and what to bring for a good night of shooting stars.
The night sky through the seasonsWhat to look for on winter, spring, summer and autumn evenings from mid-northern latitudes.