Sirius Stars

Above you, at this very moment, two trillion galaxies spin silently. A dying star has been spitting out its last light for three thousand years before reaching your retina. A comet is returning for the first time since Roman times. Seven astronauts are eating their dinner four hundred kilometers above your head, and their space station will cross your sky in exactly eleven minutes.

The sky has never been empty. We just didn't know how to look.

Sirius was designed for that.

The app knows where you are, what time the sun will set, when the moon will rise, what clouds will appear tomorrow, and how much light your city emits into the atmosphere. It cross-references your GPS location, the local weather, the global light pollution atlas, the magnitude of each object, and the equipment you own—naked eye, binoculars, telescope—to tell you only about your sky. Not some abstract planetarium for a sixth-grade class. The sky above your head tonight.

You'll find out if Saturn is visible tonight, and until what time. You'll know if the Orion Nebula will pierce the bright glow of your city, or if you'll have to drive to a darker sky to see it. You'll know that next Tuesday, a meteor shower will fall on the Northern Hemisphere, and that you'll have to get up at 4 a.m. to make sure you don't miss anything.

And when something exceptional is about to happen, Sirius will warn you. The ISS is about to pass overhead. An aurora borealis whose probability suddenly climbs above 70% at your latitude. An asteroid will skim past Earth tonight. A supernova was spotted last night in a galaxy you'd never heard of. A solar flare will illuminate the upper atmosphere. You choose the topics that interest you, and the app takes care of listening for you.

Sirius also keeps track of what's happening. A calendar displays the next thirty days, each eclipse, conjunction, full moon, and upcoming planetary opposition. Observation missions invite you to focus your gaze on specific objects, like a cosmic hunting log. And every day, a news feed relays what's exciting the world of astronomy: the latest exoplanet discovery, the mission launching, the photograph just taken from the major telescopes.

Around you, others are watching. A gallery brings together French-speaking amateur astrophotographers and their images: the Milky Way above the Pyrenees, M31 photographed from a balcony in Montreuil, a partial eclipse captured with a telephoto lens on a Sunday morning. And you, too, can join in. Publish your own photos, share your outing, show what you saw last night, from your garden or from a summit in the Mercantour mountains. Others comment, like, and reply. You're no longer just a spectator in the community; you become a participant. Observing the sky has always been a collective endeavor; Sirius is simply trying to recapture that.

The app is free, entirely in French, and ad-free.

You don't need a telescope. You don't need to know the constellations. You don't need to be special to appreciate what's happening above you.

You just have to look up.

Sirius. The universe in your pocket.