Reaching out for testers of the Mobile App! (Celeste)

[alinnman]

Call out for beta testers!

Celeste is in production!

The Celeste app has now reached production in Google Play, being available for download here

There will however be some post-production changes, likely smaller stabilization fixes and/or minor feature additions.
For this you can participate in the testing tracks, to get access to new features before being released.
The teams involved in pre-production testing are still active and anyone in there will not be automatically removed.
But newcomers are welcome.

Background

With GPS jamming incidents hitting 1,600+ ships daily in conflict zones and growing concerns about GPS reliability, I've developed "Celeste" - a celestial navigation app for Android that provides real backup when GPS fails.

What makes this different:

Calculates your position from celestial sights (sun, moon, planets, stars).
Shows your position on maps on the Android unit.
Broadcasts positions via NMEA 0183 to your existing chart plotter over WiFi.
Works completely offline - no internet needed offshore.
Shows your celestial fixes directly on marine electronics (Garmin, Raymarine, etc.).
Combine it with a solar-powered battery to get true independence.

Perfect for:

Blue water cruisers seeking GPS independence.
Anyone concerned about GPS jamming/spoofing.
Backup navigation when electronics fail.
Learning traditional celestial navigation.

Want to join?

Seeking dedicated beta testers for Google Play validation. Should be willing to test over 2-3 weeks and provide feedback on future changes.
Requirements: Android device (version 13-16), interest in navigation
Bonus: Experience with marine electronics, celestial navigation knowledge
Owning a sextant and knowing how to use it is a great plus, but the app can easily be tested with "sextant simulators" such as Frank Reed's "GPS Antispoof" or "GPS Antispoof Pro".
The app is open source (MIT license) and will be free with no ads. This is about creating reliable backup navigation for the sailing community.
Interested? Reply here or contact the test group https://groups.google.com/g/celeste-app-development-and-testing
To start testing, I will need your Gmail address (used on your Android device(s))

The app has a limited number of features, and testing it won't require a substantial amount of work.

Test plan

Downloading the app

The app can be downloaded using this link when I have added you to the test channel. To do this, I need the Gmail account you use for your Android unit. I will reach you through email, Reddit private chat, or similar to sort this out.

When testing

Report back to me any show-stopping bugs.
Use screen dumps to show any visual issues (fonts, display, etc).
When ready, report back to me about your findings. Also, report the phone model you used, including the Android version.

How much should I test?

I have built a four-level test plan. For most testers, I only wish you to perform level 1 (Basic tests). Going further requires knowledge about celestial navigation.

1. Basic tests

• Check starting behaviour (splash screen). Check for excessive startup time. (Should be less than 10 s).
• Check screen resolution issues and font display problems.
• Press the "Perform sight reduction" button. Should give a coordinate and activate the "Show map" button.
• Press the "Show map" button. Should show a map of the made sight reduction. Try to zoom out in the window.
• Switch back to the app window.
• Check the "Show help" window. Should show the online help in a separate browser window.
• Switch back to the app window.
• Switch to other apps and then re-switch to Celeste. Verify that the app isn't disturbed after having been inactive.

The following tests require some knowledge of celestial navigation.
Before going further, start by reading through the online help. This documentation is also bundled in the app (under the "Show Help!" button). You don't need to read it carefully at first, but know where to find the documentation in case you need it later.

2. Simple cel nav test

• First, test the clipboard operations. The buttons "Paste Config" and "Copy Config" will transfer your configuration into a JSON string. Try to enter it into a word processor or other similar app of your choice (Google Docs is a good choice). This copy-paste workflow will be necessary to handle if you build up a library of sight reductions.
• Install the app "GPS Anti-Spoof" or "GPS Anti-Spoof Pro". It works as a "sextant simulator".
• Register altitudes of stars, planets, sun, or moon from your location. Take careful notes with pen and paper.
• Enter the Altitude and time data into the Celeste App.
• Attempt new sight reductions.
• Check carefully if you can gain a correct position. Use the map view function for troubleshooting.

3. Full-blown cel nav test

This requires the operation of a real sextant and practicing normal routines for celestial navigation.
I won't go through this here, since the tests will depend heavily on your navigation activities. You can use the app as a quick tool to perform the sight reduction work.

4. Integration with marine plotters

Check the NMEA-0183 section of the online help. Integrate the app with your plotter device. Check if everything works.
A quick example can be found in this demo video.

Checking out the app right now

A quick demo can be found here.
You see the phone to the right, where we have entered sextant and chronometer (clock) readings for three stars on a late night in April 2025 on an island in the Stockholm archipelago. The question is: Where are we?
We perform a sight reduction, and we can now see the location in the following ways

1. Displayed directly in the app window as latlon coordinates.
2. As a detailed map using the "Show Map!" button. This shows the location and also the circles of equal altitude. We zoom out, and we can see the three GPs in different locations in the world.
3. To the left, we have a marine plotter. As soon as we perform the sight reduction, the current location is updated. We zoom in to see the exact location.

Fair winds!