A free AR star map that runs in your browser
Astroneo is a free augmented-reality sky map that works in a mobile browser, with no app to install and no account needed to look. Point your phone at the sky and it shows you the stars, planets and constellations genuinely above you, computed for your exact location and the current moment. Switch the camera on and the sky is drawn over your real surroundings.
Almost every augmented-reality star map is a native app download. The browser planetariums that exist generally draw a chart without tracking your device at all. This one does both in the browser, which is the whole reason it exists.
Why browser-based matters
| Astroneo | Typical AR star app | |
|---|---|---|
| Install required | None — opens in the browser | App Store / Play download |
| Storage used | Nothing kept on the device | 100–400 MB typical |
| Cost | Free | Free tier with paid upgrade, or paid |
| Works on a shared or borrowed phone | Yes, just open the link | Needs an install and often a sign-in |
| Sharing | A link anyone can open | A store listing to download first |
An installed app can do things a web page cannot — run offline, stay resident, use the sensors more aggressively. If you are a regular observer, a dedicated app is still worth having. This is for the far more common case of wanting to know what that bright thing above the roofline is, right now, without installing anything.
How accurate is it?
Each object is converted from its catalogue right ascension and declination into an altitude above your horizon and an azimuth around it, using the local sidereal time for your longitude. That is the same calculation an observatory uses to point a telescope. Two corrections that casual sky maps usually skip are applied:
- Precession.Catalogue positions are stored for epoch J2000, but Earth's axis has moved since. In 2026 that is about 0.2 degrees across the whole sky, growing by roughly 1.4 arcminutes every year. Uncorrected, it shifts everything by a constant offset.
- Atmospheric refraction. The atmosphere bends light downward, so every object appears higher than it truly is — by 29 arcminutes at the horizon, which is wider than the Moon, and still 5 arcminutes at 10 degrees up.
Planet positions are computed from orbital elements for the current date rather than being fixed to the background stars, and the Moon is drawn at its real illuminated fraction with its bright limb turned toward the Sun — which is why a low crescent correctly appears to lie on its back.
What you can see
- 8,898 catalogued objects, coloured by real surface temperature from their spectral class
- All 88 constellations with their IAU figures
- The Sun, Moon and seven planets, positioned for right now
- 20 deep-sky objects — Andromeda, Orion Nebula, Pleiades, both Magellanic Clouds
- The Milky Way, thickening toward the galactic centre
- Below-horizon sky, through translucent ground when you look down
How to use it
- 1Open the map. Open the sky map in your phone browser. Nothing is downloaded.
- 2Allow location. Allow location access so the sky is computed for where you are standing. If you decline, a default location is used and you can still look around.
- 3Turn on compass tracking. Open the menu and switch on compass tracking. On iPhone, accept the Motion & Orientation prompt. The view now follows wherever you point.
- 4Point at the sky. Raise the phone toward any part of the sky. Stars, planets and constellation figures are drawn in the positions they genuinely occupy above you.
- 5Overlay the camera. Switch on camera view to draw the sky over your live surroundings, which makes it far easier to match a label to the real point of light above a roofline or tree.
Common questions
Is there an AR star map that works without installing an app?
Yes. Astroneo runs entirely in a mobile browser. Open the sky map, allow motion access, and the view follows wherever you point the phone; allow camera access and the stars are drawn over your live surroundings. Nothing is downloaded and no account is needed to look around. Most augmented-reality star maps — Star Walk, SkyView, Sky Tonight, Stellarium Mobile — are native app installs, and the browser planetariums that exist generally render a chart without tracking the device.
Is the sky map free?
Yes, the sky map is free to use and there is nothing to buy. Creating a free account unlocks saving stars and logging observations, but the map, the catalogue and the AR view cost nothing.
How accurate are the star positions?
Positions are computed the way planetarium software computes them, not approximated. Each object is converted from catalogue right ascension and declination into an altitude and azimuth for your exact latitude, longitude and the current instant using local sidereal time. Catalogue coordinates are precessed from epoch J2000 to today, a correction of about 0.2 degrees in 2026 that grows by roughly 1.4 arcminutes a year, and atmospheric refraction is applied below 20 degrees altitude, where it reaches 29 arcminutes at the horizon — wider than the Moon itself.
What can I see on it?
Nearly 8,900 catalogued stars, all 88 IAU constellation figures, the Sun, the Moon in tonight's real phase, all seven planets, and 20 bright deep-sky objects including the Andromeda Galaxy, the Orion Nebula, the Pleiades and both Magellanic Clouds.
Does it work on iPhone and Android?
Yes. It uses the standard web device-orientation and camera interfaces, so it works in Safari on iOS and Chrome on Android. On iOS you will be asked once to allow Motion & Orientation access; on both platforms the camera overlay requires a secure https connection, which this site uses.
What star is that? How do I identify something I can see?
Hold the phone up toward the object with AR mode on. The map rotates to match, and bright stars and planets are labelled on screen. Tap a label to open a full page on that object. If the alignment looks slightly off, phone compasses drift near metal and indoors — use the compass offset slider in the menu to nudge it until a star you recognise lines up.
Why can I see fewer stars than on a clear night?
The map models sky brightness rather than drawing every catalogue entry. Twilight, moonlight and light pollution each raise the background and hide faint stars, exactly as they do outdoors, so the number of visible stars changes with the real conditions.
Can I see stars below the horizon?
Yes. Tilt the view downward past about eight degrees and the ground becomes translucent, showing the stars beneath your feet — the ones that have already set, or that have not yet risen. Most sky maps simply hide everything below the horizon.