Clear skies,
under control
Astro weather, cloud maps, ISS passes, the Moon, light pollution and planets — everything to catch the perfect night for observing.
Free · no ads in the observing tools · Android
Everything for one perfect night
The tools that help you decide when and where to go observing.
Astro weather
Hourly forecast of cloud cover, humidity, wind and sky transparency with an observing-quality score.
Cloud map
Interactive multi-day cloud heat-map by altitude layers around your location.
Satellite passes
Live ground-track map and schedule of visible ISS, Tiangong and Hubble passes with alerts.
The Moon
Phases, illumination, rise and set, calendar and eclipses — the Moon is the main source of night-time glow.
Light pollution
Worldwide light-pollution levels so you can find dark skies near you.
Auroras
Current Kp index and aurora probability so you never miss a burst of activity.
Planets
Planet visibility, rise and set times and the best moments to observe.
Tonight's targets
Ranked object recommendations for observing and imaging under your conditions.
NASA & news
NASA's Astronomy Picture of the Day, solar activity and fresh space news.
Catch the next clear night
Install AstroTools and plan your observing wherever you are.
From the blog
All articles →How to pick a clear night for observing
Sky transparency, cloud cover, humidity and the Moon — four factors that decide whether a session succeeds. Here's what to look at when planning.
When and where to see the ISS with the naked eye
The International Space Station is the brightest human-made object in the sky. Here is when it's visible, what a pass looks like, and how not to miss it.