100 Hours Under One Sky

Be part of a global stargazing event

Try four simple stargazing challenges to win badges. Find star patterns and a planet in the night sky.

Come back and join us any time during the 100 Hours (1-4 October 2026) to complete challenges and add markers to your town or city on our UK & Ireland map.

Add to calendar

First choose a marker and search for your location

Your marker will be added to your pin when you complete challenges during the 100 Hours

Explore the map to see who is taking part

We look forward to joining you Under One Sky, 1-4 October 2026!

100 Hours Under One Sky is a non-profit project led by the UK's International Astronomical Union (IAU)'s National Outreach Coordinator (NOC) team, with project partners Go Stargazing and the Republic of Ireland IAU NOC team. The project is funded by the IAU Office of Astronomy Outreach and the UK Federation of Astronomical Societies, and has also received support from the British Astronomical Association and Royal Astronomical Society. This project is part of the IAU's 100 Hours of Astronomy global event.