AOAC 2026 has been
cancelled.
Due to sudden circumstances that we could not have foreseen, the AO Guide Astrophysics Challenge will not run this year. The Open Round scheduled for 16 August 2026 will not take place, and no further rounds will be held this season.
To everyone who registered, prepared, and gave us their time, we are deeply sorry. You deserved better than an announcement this late, and that is on us.
Questions? Write to aoac@aoguide.app
Important Announcement
AOAC 2026 has been cancelled.
Due to sudden circumstances that we could not have foreseen, we are unable to run the 2026 AO Guide Astrophysics Challenge. The Open Round on 16 August will not take place, and no further rounds will be held this season.
We are deeply sorry. We know how much preparation you put in, and we know an announcement this close to the exam is the worst possible time to receive it. The responsibility for that is entirely ours, and we apologise unreservedly to every one of you.
Registrations are closed and no exam will be held. The 2025 archive stays online and open to everyone.
If you have any questions, write to aoac@aoguide.app and we will answer personally.
Try solving this.
No formulas. Just reasoning.
Starry Night Over the Rhône, Vincent van Gogh, 1888
Determine the month in which the painting above, Vincent van Gogh's iconic Starry Night Over the Rhône, was drawn. Assume it was painted at midnight.
This is the kind of problem AOAC 2026 was built around. We're sorry you won't get to sit the paper this year.
What AOAC 2026 Was Built To Be.
None of the rounds below will run this year. We're leaving the description here so you can see what was planned — and what we hope to be able to offer in a future season.
The Open MCQ
A fast-paced, exclusively multiple-choice exam designed to test foundational physics and astronomy knowledge.
The Playground
For those who cleared the MCQ: a 3-day Invitational window to write custom code and solve non-linear differential equations.
Learn Something New
Whether you are a gold medalist at the IOAA or just starting out, there was meant to be a question for everyone, aiming to teach you something you never knew before.
Start Training Today
Everything you need to master olympiad astrophysics is completely free.