OmegaLearnHow to Prepare for the USA Astronomy and Astrophysics Olympiad (USAAAO)
HighWhat is the USAAAO?
The USA Astronomy and Astrophysics Olympiad (USAAAO) is the national competition that selects the US team for the International Olympiad on Astronomy and Astrophysics (IOAA). It runs three proctored rounds across the year: a First Round of about 30 multiple-choice questions in February, the free-response National Astronomy Competition (NAC) in April, and a two-part theory-and-practical Third Round in June. All rounds follow the IOAA syllabus, spanning positional astronomy, celestial mechanics, photometry, stellar and galactic astrophysics, and cosmology.
Format
A ~75-minute, ~30-question multiple-choice First Round, then a ~2.5-hour free-response NAC, then a two-part (theory and practical) Third Round. A scientific calculator and a constants table are provided or allowed.
Who can enter
Anyone may take the First Round, but only high school students who are U.S. citizens or permanent residents can be selected for the US IOAA team, subject to IOAA age and grade limits.
When & how
Registration opens in January; the First Round is held in February, the NAC in April, and the Third Round in June. Exams are administered online (via Gradescope) with in-person proctoring.
How to advance
Score above the First Round cutoff to reach the NAC. The top 15 eligible NAC scorers join online training and take the Third Round; a weighted score (40% NAC, 60% Third Round) selects the top 5 for the IOAA team.
Official Information
USAAAO official website
The home of the USA Astronomy and Astrophysics Olympiad, with announcements, registration, and the current competition timeline.
View βUSAAAO selection process
The official breakdown of the three-round selection process, from the First Round through the Third Round and IOAA team selection.
View βUSAAAO FAQs
Answers to common questions on eligibility, calculator rules, exam format, and key dates for the current cycle.
View βIOAA official website
The International Olympiad on Astronomy and Astrophysics, the world competition the top five USAAAO students advance to.
View βUSAAAO recommended resources
The organization's own list of recommended textbooks, the IOAA syllabus, and study tools for preparation.
View βPractice Tests
Past USAAAO and IOAA papers are the best practice available. Work through the First Round for speed, the NAC for full written solutions, and IOAA theory papers to stretch yourself, always grading against the official solutions.
USAAAO past exams & solutions
The official First Round and National Astronomy Competition archive, the single best source of on-target practice for the US competition.
View βIOAA problems from past olympiads
Full theory, data-analysis, and observational papers from past International Olympiads, the next level of difficulty after the USAAAO.
View βIOAA solutions archive
Worked solutions organized by year and topic, so you can check your reasoning after attempting the papers under time.
View βIOAA syllabus (via USAAAO resources)
The official IOAA syllabus and physical-constants sheet, a useful map of every topic worth mastering before exam day.
View βPaid Courses & Classes
Astronomy olympiad prep is a smaller field than math or physics, so dedicated courses are limited. Most top students self-study with the textbooks and past papers above, but a few programs offer structured guidance.
PhysOlymp Academy USAAAO prep course
A structured USAAAO preparation course covering the first round and beyond, taught with past olympiad problems.
View βAdroit Education astronomy olympiad program
An overview and prep program for the USA Astronomy and Astrophysics Olympiad aimed at motivated high school students.
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