Astrarium

Choose a place and a time, and Astrarium draws that sky. Every position is computed on the device, so it works where there is no signal. The network is used only for comet and asteroid elements (MPC, JPL), satellite elements (CelesTrak), observed comet magnitudes (COBS) and the place picker's map tiles (OpenStreetMap) — each on your own action, each falling back to the cache.

IN 11 LANGUAGES
Japanese, English, Chinese (Traditional and Simplified), Korean, Spanish, Portuguese, French, German, Czech and Polish — the interface, and the names of constellations, stars, places and countries with it.

CATALOGUES (all bundled)
• 9,096 stars — Yale Bright Star Catalogue, to magnitude 8: all the naked eye can see
• 155 nebulae, clusters and galaxies — Messier and Caldwell, with photographs
• The 88 IAU constellations: 752 line segments from the official figures, and the classical art
• The Milky Way, from NASA's Deep Star Maps 2020 — the light of 1.7 billion stars
• Planets and the Moon from JPL DE421, with surface maps, libration and lunar age
• 16 major meteor showers, MPC observatory codes, sites worldwide

WHAT IT DOES
• Whole-sky and horizon views, pinch zoom to an arcminute
• Jump to any date, run the clock to 6000x, step by synodic month
• Planet close-ups: apparent diameter, phase, distance, orbital elements, and the moons of Jupiter, Saturn and Mars
• Meteor shower calendar: maximum in local time and UT, radiant altitude, moonlight, and an expected hourly rate from the ZHR
• Comets and asteroids from the MPC and JPL
• Satellites: the space stations and the naked-eye ones, with visible-pass predictions. Elements (TLEs) come from CelesTrak — refresh with “Download / update TLEs”, then it is all offline
• Four coordinate grids, the ecliptic, equator, galactic plane and meridian, FOV frames for smart telescopes and lenses
• Switch each layer on its own — lines, names, stars, Sun and planets, deep-sky objects, the Milky Way, the figures
• Limiting magnitude that follows twilight and moonlight, red night-vision mode, PNG/PDF export, a captioned demo

LOCATION
Your position is used only to compute the sky where you are, and never leaves the device. Decline it and pick a site or type coordinates: nothing is lost.

No ads, no account. All of the above is free, with no time limit.
AR — the chart over the camera image — is free too.
Sources and licences are listed under Credits.

ASTRARIUM PRO (OPTIONAL SUBSCRIPTION)
For observers who want to go deeper, an in-app subscription adds:
• 3D solar system map — 1.56 million small bodies, comets and spacecraft, from above the ecliptic
• Aurora forecast — NASA DONKI and NOAA OVATION, the oval on the sky and on a globe
• Proper-motion time machine — 50,000 years either way; the figures come apart
• Deep star catalogue — 2.34 million UCAC4 stars to 12th magnitude, below a 12-degree field
• Exoplanet transits, variable-star maxima and minima
• Every satellite group (Starlink, weather, science…), the world map and glob