How the predictions are made

Every day the site is rebuilt with the latest orbit of the International Space Station (NORAD catalogue number 25544), published by CelesTrak. The station’s position is propagated with the standard SGP4 model (satellite.js) every 10 seconds for the next 10 days, and the edges of each pass are refined to the second.

When a pass counts as visible

• The ISS is at least 10° above the horizon.
• The ISS is in sunlight, not in Earth’s shadow.
• Your sky is dark enough: the Sun is at least 6° below the horizon.

Brightness is an estimate of the station’s magnitude from its distance and the angle of sunlight (lower is brighter: Sirius, the brightest star, is −1.5, and Venus at its brightest about −4.9).

How they were checked

We compared our predictions with Heavens-Above for New York, London, Tokyo, Delhi, Los Angeles, São Paulo and Sydney over 3–13 November 2026. Start and end times agreed to within a few seconds, highest points to within 1–2°, directions to the nearest compass point, and brightness to within 0.3 magnitude. These comparisons run as automated tests.

Two known differences: passes shorter than about 15 seconds near the horizon may be missed, and for a few bright passes in evening or morning twilight Heavens-Above shows the pass starting a few minutes earlier, in a lighter sky, than our 6° rule allows.

The station occasionally fires its engines to adjust its orbit. Predictions more than a few days ahead can then shift, so check again on the day.

Dark-sky calendar

The dark-sky pages show, for each night, the hours when the Sun is at least 18° below the horizon (astronomical darkness) and the Moon is below the horizon, computed with astronomy-engine. For London in November 2026, dusk and dawn matched timeanddate.com and moonrise and moonset matched the US Naval Observatory to the minute; these checks also run as automated tests.

Cities

City names, coordinates and time zones come from GeoNames (CC BY 4.0). If your town isn’t listed, use your location.