Your Briefing — Satellite Passes Over You
Your briefing answers one question: what is flying over me, and when? Share your location and AstroSat works out exactly when the satellites you track cross your sky over the next 24 hours.
How pass predictions work
Share your location
Pass times depend entirely on where you are standing — a satellite visible from Berlin may be below the horizon in Madrid at the same moment.
Track what interests you
Add the ISS, a Starlink batch, a weather satellite or anything else, and your briefing covers exactly those objects rather than everything in orbit.
Read the pass details
Every pass lists when the satellite rises, when it reaches its highest point, when it sets, how long it is up, and the compass direction and peak elevation to look toward.
Know where to look
Elevation is the angle above the horizon: 0° is the horizon itself and 90° is straight overhead. A pass peaking above about 30° clears most rooftops and trees.
A satellite pass is the window during which a satellite is above your local horizon. For something in low Earth orbit like the International Space Station, that window is short — typically two to six minutes from rise to set, because the station is moving at roughly 28,000 km/h and covers a whole sky crossing in the time it takes to make a cup of tea. AstroSat computes these windows by propagating each satellite's orbit with the SGP4 model and converting its position into your local horizon coordinates: azimuth, the compass bearing to look along, and elevation, the angle up from the horizon. Passes are recalculated as time moves on, so the list stays current through the evening rather than going stale after the first one.
Frequently asked questions
What is a satellite pass?
The period during which a satellite is above your local horizon and therefore potentially observable from where you are standing.
What do rise, peak and set mean?
Rise is when the satellite comes above your horizon, peak is its highest point in your sky, and set is when it drops back below the horizon.
What does elevation mean?
The angle above the horizon in degrees — 0° is level with the horizon and 90° is directly overhead. Higher passes are easier to see.
Why do I need to share my location?
Pass times are entirely location-dependent. Without your coordinates there is no way to know when a satellite crosses your particular horizon.