Bortle Bounded Privacy Policy

Last updated: 20 October 2026

Bortle Bounded is an astronomy learning app for Android. It works without an account and without advertising, and it keeps what you do in the app on your device.

In short

• We do not collect, receive or sell any personal information.
• The app has no permission to use the internet, so it cannot send anything to us.
• Location, the camera and the motion sensors are used only on your device, only while you use the features that need them.
• Your notes, patterns and awards stay on your device unless you choose to share or back them up.
• The one-time purchase is handled by Google Play.

Information we collect

None. Bortle Bounded does not ask you to create an account, and it does not collect your name, email address, contact details, photos, videos, messages, location or usage. It has no ads and no analytics, and it does not include third-party advertising or analytics code.

Location, camera and motion sensors

If you allow it, the app uses your device's location and motion sensors to work out which part of the sky is above you and where your phone is pointing (Tonight and Sky Lens), and its camera to show the live view behind the star chart in Sky Lens's Live mode. All of this is worked out on your device. Your location is kept only while the app is open and is not saved. Camera images are shown on your screen only: they are not recorded, saved, analysed or sent anywhere. You can turn these permissions off in your device's settings at any time; the rest of the app keeps working without them.

The one-time purchase

Orion, the Plough and Cassiopeia are free. Unlocking the whole sky is a one-time purchase made through Google Play. Google handles the payment and your payment details under its own terms and privacy policy; we never see your card or payment details. The app asks Google Play only whether your Google account owns the unlock, and remembers the answer on your device so the whole sky stays open without a connection.

What the app keeps on your device

Bortle Bounded stores these on your device only:

• My Sky: your star notes, dedicated stars, personal asterisms, saved sky positions and guided tours;
• your awards and best Timed Challenge results, and the name you choose to print on award certificates, if you add one;
• your settings, such as sky darkness, the layers you show in Sky Lens, and voice and night-vision preferences.

None of this is sent to us. You can delete it all by clearing the app's storage in your device's settings or by uninstalling the app.

Sharing, backups and opening shared files

You can choose to share a star or an asterism, or to back up My Sky and your awards to a file. The app writes the file on your device and opens Android's share menu, and you choose where it goes, such as a messaging app, email or your own storage. What happens to the file after that depends on the app or person you send it to. A shared file holds only what you chose to share; a full backup holds your My Sky data, your awards and your certificate name.

When someone sends you a Bortle Bounded file and you open it with the app, the app reads that one file on your device and asks before adding anything to My Sky. Nothing is uploaded.

Voice

If you turn on Voice, star names and steps are read aloud by your device's own text-to-speech engine, chosen in your device's settings.

Children

Bortle Bounded is intended for general learners and is not directed at children under 13.

Changes to this policy

If the app changes in a way that affects your privacy, we will update this page and the date at the top.

Contact

If you have privacy questions about Bortle Bounded, contact: [email protected].