AstroClock icon

AstroClock

Holger Schoening
Science & Education Tools
Version
1.0
Size
5.2 MB
Requires
Android API 24+
4.3 / 5 · 18,357 ratings 112,513 downloads

Updated Oct 22, 2026

Quick answer

Astronomically correct 24-hour clock: the Sun is the hand, the star sky turns

AstroClock is an astronomically correct 24-hour clock.

Instead of an ordinary dial, it shows the sky exactly as it currently stands above your location: the Sun travels around the dial once per day as the hour hand, and the entire starry sky turns along with it – just as it really does overhead.

Features:

* The Sun as the hour hand of a true 24-hour clock * The co-rotating starry sky with constellations for your location * Realistic Moon phase and the visible planets * Compass / azimuth scale along the horizon * Sunrise, sunset, moonrise and moonset as markers * Location set by place name or coordinates * Usable as a live wallpaper * Home screen widget in a clear compact layout

Privacy:

AstroClock collects no data and contains no ads and no trackers. The app requests no location permission – you enter the location yourself. The only external connection happens when you search for a place by name; the search term is then sent to the free OpenStreetMap Nominatim service to turn it into coordinates. If you enter coordinates directly, no network access takes place at all.

Screenshots

AstroClock screenshot 1
AstroClock screenshot 2
AstroClock screenshot 3

What’s new

First release of AstroClock.

How to install

  1. Download the APK from the button at the top of this page.
  2. Allow “Install unknown apps” for your browser or file manager only, not for every app.
  3. Open the downloaded file and confirm the installation.
  4. If installation fails with “App not installed,” remove an earlier build of the same app first. A signature conflict is the usual cause.

Data safety

  • Every file is checked against its published SHA-256 before it is listed.
  • Files are scanned for malware on every update.
  • The permissions each app requests are listed on its own page.
  • Read the full safety policy for how we test, flag, and delist files.

Frequently asked questions

What is AstroClock?
Astronomically correct 24-hour clock: the Sun is the hand, the star sky turns
Who develops AstroClock?
AstroClock is developed by Holger Schoening.
Which Android version does AstroClock require?
AstroClock requires Android API 24 or later.
What is the current version of AstroClock?
The synchronized F-Droid version is 1.0.
Which license does AstroClock use?
The signed F-Droid metadata lists GPL-3.0-or-later.
Where is the source code for AstroClock?
https://github.com/GorArania/AstroClockApp

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