ISS across the Sun and Moon.
When the ISS, Hubble, or Tiangong slides across the disk of the Sun or Moon — a one-second event visible only along a thin band on the ground. Pick a date range, set how far you'd drive, and see every transit you can catch.
No transits in your travel radius for this date range. Try widening the radius or lengthening the dates.
What is a transit?
A transit is when one celestial body crosses in front of another from your line of sight. ISS-Sun transits are technically eclipses — the ISS passes in front of the solar disk, casting a tiny shadow on Earth (your camera). ISS-Moon transits are silhouettes against the lunar disk, often more dramatic visually because the moon doesn't blow out a sensor.
Why the geometry is narrow
Sun and Moon disks are about half a degree wide; the ISS is about 25 arcseconds at typical range. The transit shadow on Earth is just a few kilometers wide and moves at orbital speed — about 8 km/s. Predicting it requires precise orbital elements and observer-specific geometry. This is the same class of problem as solar-eclipse path computation, on a smaller spatial scale.
Transit math runs on JPL DE421 ephemerides via Skyfield, validated against NASA-published transit observations to better than 30 arcseconds. Centerlines are precomputed every 6 hours from fresh TLEs; the per-observer geometry (closest-distance, transit duration, chord) is computed at query time. OrbitaSky caches your search results for 1 hour; identical queries from the same metro area share a cache entry.