Amateur astronomy, computed
The night sky, precise for where you stand.
Free tools for satellite passes, transits across the Sun and Moon, and eclipses — computed exactly for your location, with no account and no app.
The tools, in action
Satellite Passes
Visible passes for ISS, Tiangong, Hubble, and other bright satellites.
Computing…→
Satellite Transits
When the ISS, Hubble, or Tiangong crosses the disk of the Sun or Moon — by location, with travel-radius search.
5-day forecast · centerline maps→
Eclipse Finder
Solar and lunar eclipses for the next 25 years, by location.
Total solar · 12 Aug 2027→