International Astronomy & Astrophysics Competition.

An introduction

The most accessible astronomy paper for school students worldwide.

Astronomy competitions tend to gate on geography. National olympiads — USAAAO in the US, AstroChallenge in Singapore, BAAO in the UK — require a school or regional center to register a student. IAAC is the exception. Any high-school or university student in any country can enter, and the Qualification round is a set of five written problems you solve and submit online before a published deadline — there is no proctor and no fee for this first round. (Dates move each year; see the official timetable for this year's.)

The competition has three rounds (Qualification, Pre-Final, Final) and three age groups (Junior, Youth, Senior). Finalists earn Bronze, Silver or Gold Honours; the top finishers in each age group receive cash prizes, alongside national awards for the best participants from each country.

What the rounds look like

Three different shapes.

Round	Format
Qualification	Five written problems (A–E), each worth 5 points · solve and submit online by the deadline · no proctor, no fee
Pre-Final	Supervised 60-minute exam · three problems (basic, advanced, and a research problem built on a real paper) · paid registration, financial aid available
Final	Online exam, around 30 short questions in roughly 30 minutes · digitally supervised, taken from home · cash prizes and Bronze/Silver/Gold Honours by tier

A note on style

Physics-with-astronomical-flavour.

IAAC papers are more like a physics olympiad with astronomical context than a constellation-identification test. The Qualification round asks about Kepler's laws, blackbody radiation, the inverse-square law, and stellar magnitudes; the Pre-Final asks for short derivations using these principles. Students with a physics-olympiad background tend to do well; pure-astronomy textbook reading is less directly useful than the analogous physics chapters.