Look up. Then find out why.

See what is up over your city tonight, then work out why with simulations you can change and short lessons for ages 8 to 18.

Start learning See tonight's sky

Tonight over

Preparing tonight's sky...

Looking straight up, north at the top. The cross marks the point directly above you.

Worked out in your browser from published orbital series, so the map still works with no connection.

Where to start

Simulations

Small working models: the Moon's phases, eclipses, the seasons, a planet crossing its star and more. Each one says what to change, what to watch for and which lesson explains it.

Try the transit simulation

A planet crossing its star, and the dip it makes in the star's light.

Lessons and learning paths

For readers aged 8 to 18: guided paths from the Sun out to black holes, with a quiz on each step that explains every answer.

Start learning

Saturn and its rings, photographed by Cassini

Reading level

Saturn is the second-largest planet and the most famous for its rings - bright bands made of countless chunks of ice and rock, each circling the planet like a tiny moon.

Tonight's Sky

A star map for your city, the next Space Station passes and where to look for them, and a calendar of eclipses and meteor showers. You can also make a postcard of the sky on your birthday.

Open the sky map

Orbit simulator

Propagate an orbit around Earth, Mars or the Moon, then read its ground track, ground-station passes and eclipse periods. The same engine finds the Space Station passes on the sky map.

Open the simulator

Ground track, 51.6° inclination, two orbits The shaded part of the map is in night right now.

Learning paths

All learning paths

Short runs of lessons in a set order. Start with any of them.

Stars over Baghdad: Arab and Islamic Astronomy Course · 10 modules Astrolabes, observatories and the astronomers who measured the sky, with a certificate at the end. Modern Astronomy: the UAE in space Module · 6 milestones From the first Emirati satellites to the Hope probe at Mars, with checks along the way.

In English, French and Arabic

Look up. Then find out why.
Levez les yeux. Puis comprenez pourquoi.
ارفع بصرك إلى السماء، ثمّ اعرف السبب.

Arabic: Laid out right to left in full, not just translated.
Reading levels: Ages 8 to 11, 12 to 14 and 15 to 18, in every lesson.
Offline: Installs from the browser and keeps working without a connection.
Cost: Free. You don't need an account to learn.