About AstroPilot
AstroPilot is a free web app for amateur astronomers and stargazers. For your exact location it tells you whether tonight is worth observing — cloud at three heights, seeing, transparency, dew and moonlight, hour by hour — which objects your telescope, binoculars or naked eyes can show tonight, and when and where to look. It also has an interactive sky chart, an observing planner and an observing journal.
Questions
Is AstroPilot free?
Yes. Every feature is free. A free account is optional: it saves your locations, telescopes and eyepieces, and your observing log. Donations help pay for hosting.
Do I need to install anything?
No. AstroPilot runs in any modern browser on a phone, tablet or computer. You can also install it as an app from the browser menu; once installed it keeps working at a dark site without signal.
How does AstroPilot decide whether tonight is good for stargazing?
It combines an astronomy-specific weather forecast for your exact location — cloud at three heights, seeing from jet-stream and wind-shear data, transparency from humidity and aerosols, and dew risk — with how dark the night gets and how much moonlight there is, hour by hour, into a score from 0 to 100 and a 7-night outlook.
Which objects can I see with my telescope?
Tell AstroPilot what you observe with — the naked eye, binoculars or a telescope, or your own gear with its eyepieces — and it rates every object from easy to out of reach for your sky's darkness, your instrument and tonight's Moon, and says when each one is best placed.
How accurate are the positions and times?
Positions are computed with astronomy-engine (VSOP87 and ELP theories) and checked against NASA/JPL Horizons and the US Naval Observatory: Sun and Moon rise and set times agree to about a minute and planet positions to a few arcseconds.
Where does the weather data come from?
From Open-Meteo's numerical weather models (with ECMWF, GFS and ICON as a cross-check), Copernicus aerosol forecasts and 7Timer's astronomical forecast. The cloud map shows EUMETSAT's Meteosat satellite images for the last few hours, then Open-Meteo's hourly cloud forecast for the week. Sky darkness for a new place is estimated from the 2025 World Atlas of Artificial Night Sky Brightness.
Data and methods
- Positions of the Sun, Moon and planets: astronomy-engine (VSOP87 and ELP), checked against NASA/JPL Horizons and the US Naval Observatory.
- Sky brightness: Bortle class or SQM reading, airmass extinction and moonlight from the Krisciunas & Schaefer (1991) model; new places are estimated from the World Atlas of Artificial Night Sky Brightness (D. J. Lorenz, 2025).
- Visibility: contrast against the sky background (Blackwell's threshold data, as modelled by Crumey 2014), at the best magnification your instrument offers.
- Events: meteor-shower peaks from the International Meteor Organization, eclipses and conjunctions computed for your location, comets from NASA/JPL, the moons of the planets from IMCCE's L1 theory and JPL Horizons.
- Weather: Open-Meteo numerical weather models, Copernicus aerosol forecasts and 7Timer.
- Catalog: OpenNGC (CC BY-SA 4.0) and classic double stars; star chart data from d3-celestial (Hipparcos).