Stellar Sky

Hold your phone up and see what is actually above you: the bright stars, the shapes they make, the planets, and the space station going over.

Hold your phone up to the sky and Stellar draws what is really there.

Not a professional catalogue of a million objects you will never see. About 200 stars — the ones you can genuinely pick out with your own eyes on a decent night — each one named, joined into the shapes people have been recognising for thousands of years.

WHAT YOU GET

• The bright stars, by name. Sirius, Betelgeuse, Vega, Antares, the Southern Cross. • 22 constellations and asterisms, drawn as faint lines you can turn off. • The Sun, the Moon with its current phase, and all seven planets — positions computed on your device from real orbital elements, not approximated. • The International Space Station, tracked live, including whether it is sunlit and therefore actually visible — and a reminder before a pass worth going out for. • The next meteor shower worth staying up for, with the Moon taken into account. • Switch on Stars and 8,600 fainter ones fill in behind — every star a truly dark sky can show you. • Search for anything and an arrow leads your eye to it. • Pinch to pull a constellation closer.

ACCURATE, AND CHECKABLE

Planet positions are computed from JPL's orbital elements and agree with NASA's own Horizons ephemeris service to within arcseconds. The Sun and Moon come from standard astronomical algorithms, with the Moon corrected for where you are standing on the Earth rather than its centre. If Stellar says Saturn is there, Saturn is there.

QUIET BY DESIGN

No account. No advertising. No tracking. No analytics. Stellar collects nothing about you — your location is used on your device to work out which stars are above you and is never sent anywhere. The app asks the internet one thing: where the space station is. (If you type your town in instead of sharing location, Apple's maps look that up.)

Works without location if you would rather not share it — just tell it which town you are in. Works indoors, too: the sky is drawn on black, not over a camera picture, so you can find tonight's stars from the sofa.