Star Count 2021: measuring light pollution

A young boy points to the night sky as his dad looks at a notepad beside him
Look to the skies and count what you can see as part of our annual Star Count Abigail Oliver / CPRE

Each year, CPRE asks the nation to help measure light pollution in their area by getting starry-eyed with us and counting visible stars. Our 2021 Star Count closed in February: what next?

We think that dark and starry skies are a special part of our countryside. Nothing beats looking upwards to see velvety blackness, with twinkling constellations as far as the eye can see.

Our buildings and streetlights emit light, though, and this can affect our view of truly dark skies. We want to make sure that we can all enjoy starlit nights, and each year, we ask for your help in measuring what effect light is having on our views of the galaxy.

What is Star Count?

The best way to see how many stars we can all see in the sky is… to count them! So we asked people from all across the country to become citizen scientists and look heavenwards from home for one night. We’ll let you know the results once we’ve crunched the numbers, and we’ll share them here.

In 2021, we asked everyone to take part from home, and thousands of you stargazed from your gardens, balconies, doorsteps and bedroom windows!

Make a note of the stars you can see to help us create a map of where light is leaking into our night skies | Abigail Oliver / CPRE

Your results from Star Count help us make a map of where star-spotters are enjoying deep, dark skies. By showing on a map where light pollution is most serious, we can work with local councils and others to decide what to do about it. You can see the 2020 results, and the map of what we discovered, here.

Star Count is supported by the British Astronomical Association.

What next?

Our 2021 Star Count took place on 6-14 February 2021.

So what’s happening now? We’ve sent the lovely data that thousands of you gathered for us to the data scientists who’ll be crunching the numbers to find out which parts of England have deep, dark skies – and where star-spotting is almost impossible. We’ll be sharing the results in the spring, so visit this page to find out what we discover or better still, sign up for our regular emails with updates.

Camping under a starry night sky

Our work on dark skies

Starry skies are one of the most magical sights the countryside can offer. Light pollution not only limits our views of these skies, but also disrupts wildlife’s natural patterns. Learn more about our work to reclaim our dark skies.

CPRE's dark skies work