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About this app

"Contribute to a world-wide citizen science project." (The Guardian)
"Find out exactly how bad the light pollution is." (Chandra Clarke, citizensciencecenter.com)
"The app couldn't be easier to use, and you can even learn different constellations along the way." (Nicholas Fordes, plos.org)

The Loss of the Night app turns your eyes into a light meter, allowing you to become a citizen scientist and report how bright the night sky is where you live!

In many parts of the world, the night sky shines with wasted artificial light from poorly designed street lamps. Skyglow outshines the stars in the skies, and dramatically changes the natural nighttime environment. Scientists are concerned that light pollution might have a big impact on nocturnal ecosystems, but they have very little information about how bright the actually sky is worldwide, or how skyglow is changing over the years.

You can help monitor skyglow using this app! It's based on Google's Sky Map, and lets you make measurements with a very sensitive, stable, and well understood light meter: your eyes! All you need to do is look for certain stars in the sky, and tell us whether you can see them or not. Using the Loss of the Night app is both fun and educational, and it also generates important scientific information that might help to protect the environment in the future.

After you've finished your measurement, your data will be anonymously sent to the GLOBE at Night project. You can see it on a map, check how accurate your measurment was, track changes over time, and compare it to other observations from around the world at http://www.myskyatnight.com.

Counting stars is a great experience and family activity, and you might find that you learn the names of stars and constellations without even trying. Students can use the app to measure skyglow and star visibility for their own science projects, and at the same time be part of a global citizen science network. The most important information for this project comes from brightly lit places where you can't see many stars, but you're welcome to use it in places where you can still see the Milky Way. If you’re lucky enough to be in such a place, let others know!

Satellites look at the ground, not the sky. By comparing the skyglow to the ground brightness, you will help communities learn what types of lamps light the streets instead of the sky. Hopefully in the future, cities will save energy and money, while having appropriately lit streets, dark bedrooms, and a sky once again full of stars.

Lots more information, including details of preliminary results, is available on the project blog: http://lossofthenight.blogspot.com and the campaign website of seeing stars Leiden: https://seeingstarsleiden.pocket.science/

You are welcome to get into contact with the light pollution researchers from Verlust der Nacht that built this app, and learn about their other projects (https://www.verlustdernacht.de). The app also provides some basic information on the history, importance, and consequences of artificial light at night.

This project was sponsored by the Federal Ministry of Education and Research (Germany).
Updated on
Sep 6, 2023

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
This app may share these data types with third parties
No data collected
Learn more about how developers declare collection
Data is encrypted in transit
Data can’t be deleted

Ratings and reviews

787 reviews
Marco Micheli
April 29, 2022
After successfully using this app for a few years, unfortunately I have to echo the authors of the last few reviews and confirm that a recent update made the app unusable. It would be great if the developers could fix it, it's a very cool app and to my knowledge there are no Android alternatives to its capabilities. Edit: The developers released a new version, and it seems to work again now. I will try it as soon as the sky is clear. Thanks and congrats for the great app!
6 people found this review helpful
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Pocket. Science Citizen Science apps
April 29, 2022
We have finally managed to solve these issues with release 2.3.9. If not, please let us know!
Hana Oshima Piano
March 2, 2023
I absolutely love the function and insight this app provides. One thing I've noticed is that the transmission status has been "waiting" since November 13, 2022, so none of the measurements since then has been sent in. If there is a way to fix this please let me know!
3 people found this review helpful
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Pocket. Science Citizen Science apps
March 14, 2023
Hi. The app is fully functional. The observations are queued because the Globe at Night is moving to a new server.
Dominic Ryan
November 27, 2023
Fantastic app to bring the very significant issue of light pollution to people's attention in a constructive way. No problems with the app, just wish there was an option to view measured values in a map view.
1 person found this review helpful
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What's new

We have a new storage system for your observations using the open science cloud.