Street lamps, illuminated signs and buildings – lights at night improve safety and make cities more attractive, but have also been shown to have negative effects for humans and animals. The more light there is, the fewer stars you can see in the night sky. How many stars can you see where you live?

Important update: Project closed (16th of March)

We are now analyzing the data from the observations reported in. A popular science report will be published on this webpage by the beginning/middle of May 2020.

The Star-Spotting app will be available for use until the end of the year, so it’s not too late to measure the light pollution levels where you live. Your observations will not be a part of the results published in May, but will be saved for future science studies. 

Thank you for participating in the Star-Spotting Experiment!

It’s easy to take part in the Star-Spotting Experiment. All you need is a cardboard tube, a DIY-protractor and the app ”The Star-Spotting Experiment”. Illustration: Lotta Tomasson / VA.


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 contribute to scientific research about light pollution by counting stars in the sky, while discovering the level of light pollution in their own neighbourhood.

Here’s how to participate

Do you want to help reseachers map the light pollution level in your local area? Great! It’s easy to participate, you will only need:

  • A cardboard tube (e.g. a kitchen paper roll), a bit of string, tape and a protractor to make your measuring tube and a compass. You can find the protractor in the instructions at page 14-15.
  • Download the app ”The Star-Spotting Experiment”/”Stjärnförsöket” to your mobile or tablet. You can find it on App Store or Google Play.
  • Go out at least one hour after sunset and wait for ten minutes to get your eyes used to the darkness. Then point the tube in nine different directions in the sky and count how many stars you can see through the tube. Report this in the app along with information about the day, time, location, weather etc.


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


For teachers

The Star-Spotting Experiment covers a range of curriculum subjects and can be used with both primary and secondary classes as well as for adult education courses.

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

Participating countries

The Star-Spotting Experiment is run 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.

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

Time plan

February 2019: Project start in Sweden.
August/September 2019: Project start in UK, Ireland and Spain.
European Researchers’ Night (27-28 September 2019) the results from the data collected during early spring will be published.
Spring 2020: Publication of results.

Did you know that…

  • One third of the world’s population cannot see the Milky Way due to light pollution.
    Falchi et al.  (2016) Science Advances 2, e1600377
  • Light pollution reduces pollination by night-flying insects, which in tur affects plant reproduction.
    Knop et al. (2017) Nature 548, 206-209.
  • Lighting on buildings can confuse bats which don’t go out and hunt because they don’t realise that it is night time.
    Eklöf & Rydell (2018) Forskning & Framsteg 8, 26-33.
  • Light at night affect humans’ production of the hormone melatonin, which affects many important body functions such as our metabolism, how we eat and how we balance activity and rest.
    Navara & Nelson (2007) Journal of Pineal Research 43, 215-224.
  • Light pollutions makes it harder for astronomers to study stars in the sky.
    Puschnig (2016) Populär astronomi 1, 30-34.

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:

| Vetenskap & Allmänhet

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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| Helen Garrison

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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