How to Use the ISS Pass Predictor

How to Use the ISS Pass Predictor

Know when the ISS is above your horizon, and whether it is actually spottable.

Open the ISS Pass Predictor

What this tool answers

When does the International Space Station rise, reach maximum elevation, and set from my GPS location? Which passes are visible, twilight-only, daylight, near the Sun, or eclipsed, and roughly how bright?

When to use it (Guyana)

Passes happen year-round. Evening and pre-dawn twilight passes are easiest to spot from Georgetown (~6°N). Use GPS for your exact site; a few kilometres rarely matter, but wrong city does. Magnitudes are approximate; weather and local lights still decide the view.

Step-by-step

1. Open ISS Pass Predictor.
2. Allow location (or set coordinates), predictions are for that observer.
3. Review upcoming passes (elevation, compass bearings, duration).
4. Read sighting badges: visible / twilight / daylight / near Sun / eclipsed.
5. Check magnitude (more negative ≈ brighter) and the sky simulation trail.
6. Use next spottable when you are planning days ahead, not just tonight.
7. Go outside a few minutes early; face the rise azimuth.

How to read the results

• Max elevation: higher passes are longer and easier (watch ≥ ~20-30° when learning).
• Visible: night/twilight, Sun-lit station, not washed by daytime glare.
• Eclipsed: station in Earth's shadow; usually not seen as a bright streak.
• Daylight / near Sun: geometrically above you but hard or unsafe to hunt near the Sun.
• Sky sim: path across the local sky with brightness context vs Venus/Jupiter.

TLE/SGP4 predictions update; refresh if a pass is days away. Do not stare near the Sun.

Common mistakes

• Treating every geometric pass as naked-eye visible.
• Facing the wrong azimuth at start.
• Ignoring clouds, check Stargazing Weather.
• Expecting lab-perfect magnitudes from approximate models.

Next

• Topic: Satellite Passes
• Tools: Stargazing Weather