Nightfall Atlas
Overview
Nightfall Atlas is a mobile app that helps you learn the constellations: it scores tonight's sky, suggests what to look for, tells the myths behind the stars and keeps a journal of your nights out. It is built to work without an account and to keep your data on your device. We do not collect personal information.
Information we collect
We do not collect, receive or store any personal information on our servers. We do not operate servers for the app at all. There is no sign-up, no login and no user profile.
Data stored on your device
The following is saved only in the app's local storage on your phone:
- your chosen place (a city from the bundled list, or coordinates you typed) and its time zone;
- your level, preferred myth traditions and usual stargazing hour;
- journal entries: night, place name, constellations seen, sky conditions and your notes;
- which myths you have read, your sky goal and recent searches;
- settings such as Red Light mode, sound, haptics, motion, clock and temperature units;
- the last weather forecast and Moon data received, with the time they were saved.
This data never leaves your device, except the rounded coordinates described below.
How we use information
Your data is used only inside the app to compute darkness times, pick constellations, show your progress and fill your journal. We do not sell, rent or share your data, and we cannot see it.
Third-party services
The app talks to two free public services, only when you open the screens that show their data:
- Open-Meteo (api.open-meteo.com) — cloud forecast. When you open Tonight or Night forecast (at most once an hour per place), the app sends your place's latitude and longitude rounded to 2 decimals (about 1 km) and the list of weather fields requested. It receives hourly cloud cover, low cloud, visibility, humidity and temperature.
- U.S. Naval Observatory Astronomical Applications (aa.usno.navy.mil) — Moon data. When you open the Moon screen (at most once a day), the app sends today's date, your rounded coordinates and your UTC offset for moonrise and moonset, and only the date for upcoming phases.
As with any web request, these services can see the IP address of your connection. No name, identifier, device ID or advertising ID is sent. Their own privacy terms apply to how they handle requests.
Analytics, advertising and tracking
The app contains no analytics, advertising, crash-reporting or tracking SDKs, does not use cookies and does not track you across apps or websites. This website uses no cookies, analytics or external resources either.
Children's privacy
The app collects no personal information from anyone, including children under 13 (or 16 in the EU). It has no chat, social or public content features.
Data retention and deletion
Your data stays on your device until you remove it. In the app, Settings → Your data lets you clear saved forecasts or erase all data instantly. Deleting the app also deletes all of its data.
Your rights
Because all data is on your device, you are always in control: you can view and edit your journal in the app, export everything as a JSON file (Settings → Your data → Export), and delete it at any time. These cover the rights of access, correction, portability and erasure under GDPR and similar laws; we hold no copy that we could disclose.
Security
Data is protected by your device's own security (screen lock, biometrics, encryption). Requests to Open-Meteo and the U.S. Naval Observatory use HTTPS.
Changes to this policy
If the app's data handling changes, this page and the in-app Privacy screen will be updated before the change ships, and the date above will change.
Contact
Questions about privacy: hello@nightfallatlas.app