How to use
- Choose a city, or click “Use my location” for the most accurate times.
- Choose a satellite — the ISS, Tiangong, the Hubble telescope or a recent Starlink launch.
- By default only passes you can see are listed; open a row for its path across the sky.
- A few minutes beforehand, go somewhere open, face the “Appears” direction and look for a steady, non-blinking light moving smoothly.
Options explained
- Appears / Highest / Disappears
- Time and direction; the angle is the elevation above the horizon, 90° being straight overhead. Anything below 10° is easily hidden by buildings and trees, so it is not listed.
- Visible
- The satellite is lit by the sun while it is dark where you are (sun at least 6° below the horizon). A satellite entering Earth’s shadow fades out in mid-sky.
- Orbital data
- Orbital elements from CelesTrak, refreshed every 6 hours and propagated in your browser with the SGP4 model; times are usually right to within seconds.
Tips for spotting the station
| Tip | Why |
|---|---|
| Pick high passes | Passes reaching 40° or more are brighter, last longer and are less likely to be blocked |
| Be early | Times are given to the second; arrive five minutes early and let your eyes adjust |
| Follow the directions | It rises low in the “Appears” direction, climbs, then sets or fades out toward “Disappears” |
| Take a photo | Put a phone or camera on a tripod and use a 10–30 second exposure to capture a light trail |
China’s Tiangong station orbits at about 41.5°, so it is seen less often and lower in the sky from far northern or southern latitudes. Planning a night of stargazing? Check the moon phase calendar — a bright moon washes out faint stars — and the sunrise and sunset times.
Frequently asked questions
Why only around dusk and dawn?
Satellites shine by reflecting sunlight. In daytime the sky is too bright, and late at night they are usually in Earth’s shadow. Just after sunset or before sunrise the ground is dark while the satellite, hundreds of kilometres up, is still in sunlight.
How often does the ISS pass over?
It circles Earth about every 92 minutes, but visible passes from one place usually come in a run of several days, followed by a week or two with none. Its orbit is tilted 51.6°, so it can be seen from most inhabited places.
What does it look like?
A bright, steady white light crossing the sky in a few minutes, with no flashing red or green lights (those are planes). NASA describes the ISS as the third brightest object in the sky after the Sun and the Moon.
How do I see a Starlink train?
For a few days after launch, Starlink satellites travel in a line like a train of lights; then they climb and spread out and become hard to see. That is why only the latest launches are listed — go out within a week of launch.
Privacy
This tool runs in your browser. It only fetches public data (such as the exact time or orbital data) or passes pairing details through our server; your files, text and location are not uploaded. Server access logs record IP addresses and request URLs, used only to prevent abuse.