How it works
When you tap Show me, your browser asks if it may share your location. If you say yes, the page rounds it to about a kilometre and asks a free community ADS-B feed, through my small relay, for every aircraft within your chosen range. Most airliners and many light aircraft broadcast their position, height, speed and heading on 1090 MHz, and thousands of volunteers pick those signals up with small receivers and share them.
The page asks again every 12 seconds, and between updates it moves each blip along its track at its ground speed, so the radar glides rather than jumps. The sweep is just for looks: real ADS-B is not a radar at all, but I couldn't resist.
For satellites, the page downloads the orbits of the space stations and the brightest satellites from CelesTrak, keeps them in your browser for a few hours, and works out where each one is from where you are, every second, with the SGP4 model in satellite.js. A pass counts as one you can see when the station is high enough, your sky is dark and the station is still in sunlight.
If you type a place instead, the name goes to OpenStreetMap's Nominatim search, only when you press Look, never as you type.
Your privacy
Your location never leaves your browser except as a rounded copy sent through my relay to the aircraft feed with each request. The relay passes it on and keeps nothing, and a place you type, sent to the place search. It is not saved, not shown on screen and not put in the address bar, and I have no server that could keep it. The only thing kept in your browser is the downloaded satellite orbits, under keys starting fom:tle:, so the page does not fetch them every visit. Visits to the site are counted by Cloudflare Web Analytics, which uses no cookies. More in my privacy notice.
Questions
Do you store my location?
No. Your location stays in your browser and is never saved, shown on screen or put in the page address. To ask for planes and satellites, a copy rounded to about a kilometre goes through my relay to the aircraft feed, and a town or postcode you type goes to the place search. Nothing goes to my server, because there isn't one.
Why can't I see a plane I can hear?
Not every aircraft sends ADS-B, some fly with it switched off, and the volunteer receivers that feed the map do not cover everywhere, especially low down and far from towns. Positions can also be a few seconds old.
When can I see the ISS?
You can only see it when the sky is dark where you are and the station is still in sunlight, which happens for an hour or two after sunset and before sunrise. The page shows the next pass you can see and the next pass overhead, with the times in your own time zone.
Where does the data come from?
Aircraft come from the free community feeds at airplanes.live and adsb.lol, through a small relay of mine that only passes on the rounded position. Until that relay is switched on, the radar shows demo planes. Satellite orbits come from CelesTrak and are worked out in your browser with satellite.js. Typed places are looked up with OpenStreetMap's Nominatim, or Open-Meteo if that is busy.
What happens if a feed is down?
If the aircraft feeds do not answer, the radar switches to clearly marked demo planes and keeps trying the real ones. If CelesTrak does not answer, the page uses a saved copy of the orbits, which is fine for a few days.
Data and credits
- Live aircraft: airplanes.live and adsb.lol (data under the ODbL), through my relay, which keeps nothing. Flight links open on globe.adsb.lol.
- Satellite orbits: CelesTrak, the space stations and visual groups.
- Orbit maths: satellite.js, MIT licence (licence text).
- Place search: Nominatim, data © OpenStreetMap contributors, with Open-Meteo geocoding as a backup.
Spot something wrong? Tell me.