100 Hours of Astronomy

100 Hours Under One Sky / PROJECT WEBSITE

THURS 3 - SUN 5 OCTOBER 2025

Look up! Our mobile-phone activity encourages people to take a short time out of their day to look up from wherever they are. Simple challenges are built for success and users can win virtual badges and put their markers on our UK & Ireland map. Resources allow easy integration of the activity into in-person events, or people can simply participate from home.

With funding confirmed from the IAU, we are returning for 2025. We are working in partnership with the Irish IAU OAO NOC team to extend our activity to Ireland, with a view to extending to other countries/languages in future. We have been improving the user interface to be more accessible and easier to use, and are running a TikTok campaign funded by the Federation of Astronomical Societies.

This year’s dates overlap World Space Week and International Observe the Moon night, which is perfect for catching public attention.

LATEST UPDATES:

A YouTube video walk-through of the app is now available for Event Organisers
The 2025 Event Organiser webpage is now open, with information about how to incorporate 100 Hours into your event, and an overview of the resources available.
The Event Organisers resources Drive space is now open! This is where you can download resources to help publicise and run your event and/or 100 Hours activities.
We will be running a Zoom call for Event Organisers on Tuesday 2 September at 6.30 pm. The link will be shared via science communicator email lists and also added to this webpage shortly before the event. The call will be followed by a week-long preview period where you can check out our new version of the app (and let us know any typos or snags you spot!). The link is: https://us02web.zoom.us/j/88183634881?pwd=cinQa62XLK2nMv7Fi19dJDWmy42y8h.1 / Meeting ID: 881 8363 4881 / Passcode: 184767
The public-facing website is 100hours.online. It is currently showing a pre-event webpage that allows people to register markers and locations in advance of the event.
Download the 2024 project report here. We learned a lot and consider our 2024 pilot project to have been a great success, especially in terms of the very wide geographical spread of participants (see image below).

If you would like to support 100 Hours, get in touch. Or if you want to participate using our event organiser resources, check back here closer to date.

More information below!

The morning after: our 2024 event, “just a pilot”, attracted people from across the UK. We were told by astronomy societies that many of the participants they saw were sharing phones, so that total participation figures are likely higher than our figures suggest.

Our vision

We in the IAU OAO National Outreach Coordinator (NOC) team for the UK wanted to do something to increase the profile of 100 Hours of Astronomy in the UK, while reaching new audiences. And rather than the usual national-event model of branding up events that probably would have happened anyway, we wanted to do something genuinely innovative and new.

We came up with the idea of an online event that people could join from wherever they happened to be, publicised through social media to catch the attention of people who were not already thinking about astronomy. And making it something that could be used at outreach events too.

We have strong project partners in the Royal Astronomical Society and Go Stargazing!, and funding from the IAU Office of Astronomy Outreach and the Federation of Astronomical Societies (FAS). Thanks also to FAS and the British Astronomical Association for supporting the project last year, funding aspects of the project that we have built upon for this year.

So - let’s do this thing!

100 Hours of Astronomy is a global, mass-participation event led by the International Astronomical Union’s Office of Astronomy Outreach (IAU OAO) with the goal of making astronomy accessible to everyone. Every year, people in over 60 countries all around the world participate by doing astronomy activities during the event. Much of this activity is coordinated by the local National Outreach Coordinators.

To support this event in the UK, we are offering new, total-beginner-level astronomy activities that can be integrated into stargazing events with very little effort and/or be offered to audiences as an at-home activity. Even if you don’t run your own event, you can support the event by sharing our social media posts and resources.

Our first event was event is UK-only, and this year we will cover both the UK and Ireland. And there is no reason why we can’t grow to cover the whole world - our platform is built to allow for multiple languages and countries.

Our aims

To give beginner stargazers feelings of personal success and achievement in astronomy
To reach people in their own territory - on social media and on their mobile phones
To give people the feeling of being part of a community of participants across the UK
To offer stargazing event organisers a cheap, simple way to take advantage of our activities
To create activities that can be incorporated into World Space Week celebrations (World Space Week is 4-10 October)

Our target audiences

Primary audience: UK-based adults aged 18 - 35 years who are not particularly into science and have not previously participated in astronomy activities
Secondary audience: any children of the above
Extended audience: anyone else in the UK who wants to join in!
We are keen to reach people who experience barriers in attending outreach events and activities due to their location, accessibility, or other factors
Other audiences: people attending stargazing events run by amateur astronomical societies, science centres, and other science communicators

So What Are We Actually Doing?

Our new project is called 100 Hours Under One Sky. The core element is a mobile-friendly, app-like website which offers simple, low-barrier astronomy challenges. These involve spotting bright star patterns and Saturn in the night sky. It has a simple user interface with nice graphics, there isn’t a lot of reading required, and include Instagram-style video explanations of each challenge.

User data is saved in a local cookie. This includes the name of a chosen village/town/city to which their achievements will be added, their choice of map marker, and an automated unique iD. We do not collect detailed locations, email address, or require any form of registration.

Completing each challenge wins the user a special animation and an attractive virtual badge, which they are prompted to share on social media. Achievements are marked on a dynamic UK map which will light up with markers during the 100-hour period as people in different locations participate in the project.

The website includes absolute-beginners’ stargazing advice to help anyone who isn’t sure where to start, with links to further information. It also takes the opportunity to gently point users toward local/regional astronomy events.

This website will be marketed through social media (Instagram, and also a TikTok campaign funded by the Federation of Astronomical Socities), and through Science Communication partner organisations - can you help spread our message?

Our long-term vision is to connect everyone involved in 100 Hours within one worldwide community. Imagine a globe slowly lighting up with dots as people go outside and look up.

Video walkthrough of the App

Resources for Event organisers

The Event Organiser website is where you will find resources for people who are not running events but want to help promote 100 Hours.

If you are running a stargazing event, it’s really easy to link up to our 100 Hours event. All you need to do is to display a webpage specially designed for events. Watch markers fly in to locations across the UK, and zoom in on your area and click your location to see the achievement markers earned by your attendees. The map includes a QR-code/url to direct people to our website, where they can do the self-led activities. All you need do is to project or display this webpage for your attendees to participate and feel part of something bigger.

But! If you want to do more, we will also offer a pack of cheap hands-on activities you can use with families. Together we can create a community of people enjoying our shared night sky.

To help publicise your event, we offer downloadable packs including posters, social media resources and press releases.

Public event organisers are encouraged to register their events at Go Stargazing. This will let us know you are participating (making it easier to get more funding), and will also make your event visible to the large numbers of people who use Go Stargazing's popular site to search for things to do.

There will be an preview/evaluation period 2-9 September and a pre-preview Zoom call at 6.30pm on 2 September where you can find out more about 100 Hours and ask any questions you might have. The Zoom link will be advertised here and on the AstroMailbox email list on the day of the call, and the preview link will be shared in the same places.

Who are we?

This project has been developed by the IAU Office of Astronomy Outreach UK National Outreach Coordinator (NOC) team (all volunteers), partnered with the Ireland NOC, Go Stargazing (who are providing the technical wizardry), supported by funding from the IAU NOC fund, the Federation of Astronomical Societies, and previously from the British Astronomical Association.

Further details

Updates will be posted on the AstroMailbox email list and through other networks.

Meanwhile if you would like to partner with us, or if you have any other ideas for ways in which you could support 100 Hours Under One Sky, we'd love to hear from you.

Dr Jenny Shipway - IAU OAO National Outreach Coordinator
Gemma Kerr - IAU OAO Vice National Outreach Coordinator
James Fawcett - IAU OAO Vice National Outreach Coordinator