During 2019 and into early 2020, school pupils, scout groups, astronomers and interested members of the public went out to count stars in the night sky. The objective was to test a new method for measuring light pollution, based on the principle that the more stars you see in the night sky, the less light pollution. Thank you for participating in the Star-Spotting Experiment!

VA-report 2020:3

Download the pdf of the report here.

Our use of artificial light has dramatically changed the environment in large parts of the world. Scientific studies have shown unexpected and worrying effects on the biology of many organisms as well as on whole ecosystems, but also on human health. The problems of artificial light are commonly referred to as light pollution.

In the Star-Spotting Experiment, thousands of pupils, members of outdoor associations, other clubs and members of the public in Sweden, UK, Ireland and Spain contributed to scientific research about light pollution by counting stars in the sky, while discovering the level of light pollution in their own neighbourhood.

Some of the results:

  • A total of 1,921 observations were recorded in Ireland, Spain, the UK and Sweden.
  • In Sweden, 252 school classes, 29 scout groups and 176 individuals registered their interest in participating in the Star-Spotting Experiment.
  • For 17 percent of all observations in Sweden, no stars could be seen in the sky at all. For observations where stars could be seen in the sky, the app calculated that on average 454 stars were visible across the whole sky. This corresponds to a limiting magnitude1 of 4.5. The number varied greatly, from no visible stars to several thousand.
  • A comparison shows that the Star-Spotting Experiment achieved more or less the same results as other methods of measuring light pollution. This means that the method we developed during the Star-Spotting Experiment works well as a way of measuring light pollution!



Urban Eriksson, researcher and senior lecturer Lunds universitet. Foto: Lunds universitet.


The scientific leader of the project is Urban Eriksson, a researcher and university lecturer in physics with a focus on astronomy education at Lund University in Sweden.

Participating countries

The Star-Spotting Experiment ran in the following countries:

Public & Science, VA as a part of European Researchers’ Night in Sweden under the name ”Stjärnförsöket”.

United Kingdom
Natural History Museum, London

University College Cork & Trinity College Dublin.

Fundación Descubre, ESCIENCIA, La Palma Centre & Fundación Madri+d under the name ”Cuenta Estrellas”.


For further information:

Contact the project managers in Sweden: [email protected]

The Star-Spotting Experiment is created by the non-profit organisation Public & Science (VA), the National Resource Center for Physics Education (NRCF), Lund University, Kristianstad University, the Swedish National Space Agency, and the two science centres House of Science (Vetenskapens hus) and Umevatoriet, Sweden.

The project is run in collaboration with Fundación Descubre, Esciencia, La Palma Centre and Fundación madri+d in Spain, University College Cork and Trinity College in Ireland and Natural History Museum in London, UK.

Latest about the Star-Spotting Experiment:

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Young people in Sweden, Spain, Ireland and the UK help researchers successfully test new method for measuring light pollution

In 2019 and early 2020, school pupils, teachers, scout groups, astronomers and interested members of the public in Sweden, Spain, the UK and Ireland went out to count stars in the night sky. The objective was to help researchers to test a new method for measuring light pollution. Researchers have analysed the results and these have now been published.

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Star-Spotting Experiment shortlisted for international science engagement prize

The Star-Spotting Experiment, VA’s 2019 citizen science project to investigate light pollution, was shortlisted for the 2019 Falling Walls Science Engagement of the Year competition. Project manager, Lena Söderström was invited to Berlin in November to present the project in the final of the competition at the Falling Walls Conference. Here we talk to her about the experience.

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Swedish Star-Spotting Experiment off to a sparkling start

The Star-Spotting Experiment, this year’s citizen science project in connection with the European Researchers’ Night events in Sweden, is now well underway. Members of the public across Sweden are helping scientists to measure light pollution by counting stars in the sky and recording the data in a specially-designed app. Here we catch up with Lena Söderström, Project Manager at VA (Public & Science), who is coordinating the Star-Spotting Experiment, to find out how the project is progressing.

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