Your personal stargazing assistant and web planetarium

Open Asteria

Asteria is a free interactive night-sky map that runs in your browser. It shows the stars, planets, Moon, constellations, deep-sky objects and the Milky Way exactly as they appear from your location, at any time you choose. No installation or sign-up is needed: open Asteria and the sky is there.

What you can do with Asteria

• Explore the sky — pan and zoom across thousands of stars, the planets, the Moon and its phase, constellations and galaxies, nebulae and star clusters.
• Plan your night — see when it gets dark, when an object is highest, and how good the conditions are, including the cloud forecast and light pollution for your location.
• Find celestial events — conjunctions, oppositions, eclipses and meteor showers, each shown in the sky for your own location and local time.
• Take a guided tour of the night's highlights, or point your phone at the sky to identify what you are seeing.
• Use your own equipment — add your telescopes and eyepieces to see their true field of view on the chart.
• Save your observing places — keep your backyard, club field and dark sites in My locations, each with its sky brightness, and switch between them with one tap.
• Install it as an app on your phone or computer; it keeps working offline.

Accounts

Everything in Asteria works without an account. You can optionally create one, with your Google account or with an email address and password. Your account keeps your telescopes, eyepieces, barlows, field-of-view combinations and saved locations safe, so you can use them on all your devices; saving observing lists to it is coming soon. When you sign in with Google, Asteria receives only your name and email address, and uses them only for your Asteria account. You can delete your account at any time from within the app.

Read how Asteria handles your data in the privacy policy.

Supporters

Asteria stays free. A yearly supporter membership adds extra planning features, such as a detailed cloud forecast for up to 7 nights and a scan of the whole year ahead: Lunar from €1 a month, Solar from €2 a month, billed yearly (€12 or €24 per year).

More

• Open Asteria
• Upcoming night-sky events
• Supporter membership
• Terms of service
• Refund policy
• Privacy policy