USAAAO
United States Astronomy and Astrophysics Olympiad
Two rounds of astronomy and astrophysics exams leading to the US team for the international olympiad.
Run by USAAAO
Key facts
- Eligible grades
-
High school students
USAAAO addresses its registration guidance to high school students and publishes no numbered grade range.Source, checked 2026-09-02
- Recommended preparation
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Self-directed study of the IOAA syllabus, beyond school astronomy
Why: The exams follow the International Olympiad on Astronomy and Astrophysics syllabus, which goes well beyond the astronomy content of a typical school science course. A scientific calculator and the provided table of constants are permitted.Based on the official syllabus and content covered.This is Compete's reading of the competition's documented content, not a requirement stated by the organiser. You may enter without it.
- Compete guidance, not an eligibility restriction. Students outside this are still eligible if the official eligibility above allows them.
- Eligible ages
-
Not confirmed. This organiser may set eligibility by grade rather than age. We do not convert one into the other.USAAAO publishes no age limit on the pages checked.
- Individual or team
- Individual
- Where it runs
- In person · United States
- Entry cost
- $30 per student, or $20 per student if at least 5 students from the same school register.A separate financial aid form is available for students unable to pay; you do not fill out both. The previous listing described the fee as free or nominal, which was wrong.
- Registration deadline
- Set locally, not published as a single national date 2027 registration close not published. The 2026 close was 31 January.
- Competition dates
- 2027 dates not yet published. For reference, the 2026 cycle ran: registration 1 to 31 January, First Round 9 February, NAC 13 April, Third Exam 22 June, online training May to September, and the IOAA 25 September to 5 October 2026 in Hanoi, Vietnam.
- Difficulty
- Highly competitiveNational-level field. Expect months of structured work, and usually a coach or a strong team.
- Prizes
- Team selection and medalsNo cash prizes. Team selection and free online training for qualifiers.
What USAAAO is
USAAAO selects the United States team for the International Olympiad on Astronomy and Astrophysics. It runs two rounds of proctored written exams: a First Round open to any registered high school student, and a National Astronomy Olympiad exam for qualifiers. The syllabus is essentially first-year university astrophysics, but the First Round is accessible to a motivated student who has done physics and trigonometry.
How the competition works
Three rounds of proctored exams with multiple choice and free response questions, held in February, April and June. Proctoring is in person during a specified time interval. The First Round is multiple choice; students above a cutoff are invited to the National Astronomy Competition, a roughly 2.5-hour free response exam over the full IOAA syllabus; a Third Round exam follows. Final rankings weight the NAC at 40% and the Third Round at 60%, and the top 5 represent the US at the IOAA. A scientific calculator and the provided table of constants are allowed.
Eligibility notes
Anyone may sit the exams, but international team selection requires US citizenship or permanent residency.
Is USAAAO right for you?
- Experience needed
- You need a physics course and comfortable trigonometry. Calculus helps but is not strictly required for the First Round.
- Time commitment
- Two to four months of steady study for a competitive First Round score.
- What you actually do
- A written exam of multiple choice and free-response problems: work out a star's luminosity from its spectrum, convert between coordinate systems, calculate an orbit.
A good fit if
- You already enjoy physics problem sets
- You want a less crowded olympiad than physics or chemistry
- You are interested in astrophysics specifically
Probably not for you if
- Students who have not yet taken physics
- Students wanting an observational rather than mathematical competition
Common mistakes
- Studying astronomy facts rather than astrophysics problem solving. The exam is quantitative.
- Neglecting spherical astronomy and coordinate conversions, which are unfamiliar to most school students and appear reliably.
- Ignoring order-of-magnitude estimation, which several questions reward directly.
How to register
- Register on usaaao.org during the autumn window.
- Work through the published past exams, which are free.
- Sit the First Round online under proctored conditions.
- Qualifiers are invited to the National Astronomy Olympiad exam.
What skills you need
- Mechanics and gravitation
- Optics and radiation
- Spherical astronomy and coordinate systems
- Stellar physics
- Logarithms and orders of magnitude
- Estimation
Recommended resources
-
USAAAO official site
Registration, syllabus, and past exams with solutions.
-
International Olympiad on Astronomy and Astrophysics past papers
Free international papers, considerably harder than the First Round but the eventual target.
-
Astronomy: Principles and Practice, and OpenStax Astronomy
OpenStax Astronomy is a free full university textbook covering most of the conceptual syllabus.
Past problems and materials
Only materials the organiser or an authorised archive publishes openly are listed here.
- USAAAO past exams
Published free with solutions.
Frequently asked questions
Do I need a telescope?
No. USAAAO's rounds are written exams. Observational skills matter only at the international olympiad, and the team receives training for that.
How does it compare to the physics olympiad?
The field is far smaller, which makes qualification statistically easier, but the astrophysics content is unfamiliar to most students. The mechanics and optics overlap heavily with physics olympiad preparation.
Reviews, tips and resources from other students
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Something out of date?
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