Office for Astronomy Outreach

100 Hours of Astronomy

100 Hours of Astronomy

100 Hours of Astronomy

100 Hours of Astronomy is a yearly global celebration organised by the Office for Astronomy Outreach (OAO) that invites people of all ages and backgrounds to come together and connect with the night sky — and with the science that helps us understand it.

From vibrant cities to the most remote corners of the world, this event brings astronomy closer to communities everywhere. Through public stargazing, workshops, talks, and hands-on educational activities, 100 Hours of Astronomy sparks curiosity, encourages shared exploration of the cosmos, and invites us all to reflect on our place in the Universe.
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Gallery: 100 Hours of Astronomy

Everyone, from amateur astronomers to educators and enthusiasts, is invited to propose an event and take part in this global celebration of the night sky
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Content

100 Years of the Planetarium

Planetariums have long been a source of inspiration for children and adults alike. This year, the IAU Office for Astronomy Outreach (OAO) will team up with the International Planetarium Society (IPS) to continue the legacy of 100 Hours of Astronomy and celebrate 100 Years of the Planetarium.

With the increasing threat of satellite trails and light pollution to our skies, planetariums are dark sky oases: sanctuaries for night sky enthusiasts, exposing the public to the Universe.

Even in locations where the night sky is protected from city lights, planetariums can be a powerful educational tool for understanding the Universe and our place within it.

This year, we encourage everyone to visit their local planetarium – small, large, mobile, or stationary – and immerse themselves in the wonders of our Universe.

100 hours of astronomy

Akashi Municipal Planetarium in Japan

This year, our main hub will be the Akashi Municipal Planetarium in Japan an historic site located exactly on the 135° East meridian, where Japan Standard Time is measured. It is a fitting place to mark this global moment under the stars!.

In addition to our main hub, we have Community Nodes around the world. These are local contact points where you can get support, ask questions, and join ongoing activities near you.

Whether you're organising a big public event or a small online session, you’re part of something bigger. Let’s connect across borders and time zones to celebrate the power of astronomy, together.

Be part of the global movement, register your event today!

How can you be part of a global event?

Ways to Get Involved

  1. Apply to become a Regional Node.
  2. Plan and organise IAU outreach event between 2–5 October.
  3. Attend or support a pre-existing astronomy event near you.
  4. Promote events on social media using #100HoursOfAstronomy.


This year’s theme is “100 Years of the Planetarium”, but all astronomy events are welcome.

Main activities and events 100 Hours of Astronomy

2 October: Big Astronomy, Big Aspirations

2 October: Big Astronomy, Big Aspirations

Join the 100 Hours of Astronomy double feature! On 2 October at 2 PM UTC, the OAO will host IPS President, Shannon Schmoll, who will present the planetarium show, Big Astronomy, live on the OAO YouTube channel. This show highlights the diversity of people who work at some of the most important sites for modern astronomy and their careers.

Our second act features Ardis Herrold (Rubin Observatory), who will give us a special perspective on the next generation of ground-based astronomy in her talk, “The NSF-DOE Vera C. Rubin Observatory - The Transformative Years”. All are welcome to join this hour-long online event and engage with speakers, creators and audiences worldwide! Tune into this event at the OAO YouTube channel.
Watch live
4 October: 24 Hours of Planetariums

4 October: 24 Hours of Planetariums

Planetariums - large, small, mobile, stationary, and hand-made - are important cultural and educational centres for their communities. The OAO and IPS are celebrating the unique view from inside planetariums from across the globe, and the diverse activities that help to engage people with astronomy. 

During this 24-hour continuous event, the OAO will stream live from the Akashi Municipal Planetarium in Japan. 

This willl feature live presentations, audience Q&A, games, pre-recorded videos, and much more. Groups from more than 40 nations will be joining us in this 24-hour celebration! Join us for part (or all) of this event on the OAO YouTube channel.
Watch live

100 Hours of Astronomy | 24 Hours of the Planetarium

100 Hours of Astronomy Box

The 100 Hours of Astronomy Box was compiled to help you plan and promote your events for the 100 hours, and beyond. This resource includes:


  • Ready-to-use designs for social media, available as a template on Canva and as AdobeIllustrator files.
  • Photo and video constent forms that can be easily adapted to your event.
  • Resources to suit any need: astronomy engagement tools, guides, and templates, including Canva designs, accessibility tips, educational materials, and links to key resources.
  • And more! This is an evolving resource. Check back here for new and exciting content!

Share your event with the world

We encourage you to share your events and participate in this year’s 100 Hours of Astronomy! If your event is open to the public, please leave enough information for people to get involved—both in person and online!


Help us spread the excitement of 100 Hours of Astronomy by sharing your event on social media! Use the official hashtags so your activity can reach a global audience.


Copy the hashtags and include them in your posts, photos, or livestreams: #100HoursOfAstronomy, #IAUoutreach


Tag us in:
@IAUoutreach@oao_iau@iau-oao

OAO Astronomy Engagement Events

To highlight the incredible range of activities taking place around the world, we will feature a global calendar of events displayed on an interactive world map.

In addition, these activities will be promoted through our social media channels, helping to increase visibility, encourage participation, and connect people everywhere through astronomy.

More Information

All events must respect the general guidelines of the IAU Global Project and Themes, which promote the key role of astronomy for the betterment of science and society through collaboration and with a spirit of respect, tolerance, and peace.

If you need to change your events already on the calendar, please email the IAU Office for Astronomy Outreach Team via public@...Click to show with the subject line “100 Hours of Astronomy Calendar 2026 - Update”.If you cannot submit through this form, please email the IAU Office for Astronomy Outreach team via public@...Click to show with the subject line “100 Hours of Astronomy Calendar 2026 - Update”.