The Library of Competitions
Tian2 Editions
Three online rounds — Qualification, Pre-Final, Final — across Junior, Youth, and Senior age groups. Sat from anywhere in the world, no proctor required, no fee for the first round. 40,000+ participants, 120+ countries, running since 2019. Student and Advisor editions on file.
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 centre to register a student. IAAC is the exception. Any high-school or early-university student anywhere in the world can enter individually, and the Qualification Round is a set of five written problems submitted online by a published deadline — no proctor, no fee, no school sign-off required. That simple design choice is why 40,000+ students from 120+ countries have competed since 2019.
The competition has three rounds and three age groups. Age group is fixed at the Qualification Round submission deadline. The Qualification Round is broad and manageable; the Pre-Final introduces supervised conditions and may include reasoning about a real published research article; the Final is the hardest, short-format test with cash prizes for top performers.
46 official PDFs confirmed accessible (HTTP 200) at iaac.space/docs/: complete 7-year archive 2019–2025, all three rounds, both problems and solutions. The 2026 PDFs were not yet published at audit time. All PDFs are image-based; download from the source.
| Round | Format | What it tests |
|---|---|---|
| Qualification Round | Five written problems (A–E) · solve and submit online by deadline · no proctor, no fee | Broad astronomy and astrophysics reasoning — orbital mechanics, stellar properties, magnitudes, cosmology. The style is closer to a physics olympiad with astronomical context than a trivia or constellation paper. |
| Pre-Final Round | Supervised 60-minute exam · three problems · paid registration · financial aid available | More quantitative. Includes one problem built around a real published research article — you read a paper and reason about it under exam conditions. Calculus helps here. |
| Final Round | ~30 short questions · ~30 minutes · digitally supervised at home | Hardest stage. Fast-format but deep. Top finishers in each age group receive cash prizes; Bronze, Silver, and Gold Honours by score tier. National certificates issued to top country finalists above the minimum threshold. |
IAAC papers are more like a physics olympiad set in outer space than a constellation-identification test. The Qualification Round asks about Kepler's laws, black-body radiation, the inverse-square law, and stellar magnitudes. The Pre-Final asks for short derivations. The subjects are astronomical — you will need to know what a parsec is, what the Hertzsprung-Russell diagram looks like, what Hubble's law says — but the tool is physics problem-solving, not memorisation of the sky.
Students with a physics-olympiad background tend to do well. Pure descriptive astronomy reading is less useful than working through the analogous chapters in a physics textbook.
If you can do BPhO Round 1 and you know the Pogson equation, you can reach the IAAC Pre-Final.— Editor's note
The IAAC organisation publishes every past problem and solution PDF on their own domain. The URL pattern is stable and predictable:
iaac.space/docs/problems/YEAR/IAAC_Qualification_Round_YEAR.pdf
iaac.space/docs/problems/YEAR/IAAC_Qualification_Round_YEAR_Solution.pdf
iaac.space/docs/problems/YEAR/IAAC_Pre_Final_Round_YEAR.pdf
iaac.space/docs/problems/YEAR/IAAC_Pre_Final_Round_YEAR_Solution.pdf
iaac.space/docs/problems/YEAR/IAAC_Final_Round_YEAR.pdf
iaac.space/docs/problems/YEAR/IAAC_Final_Round_YEAR_Solution.pdf
| Year | QR + Sol | PFR + Sol | FR + Sol | Notes |
|---|---|---|---|---|
| 2019 | Available | Available | Available | Founding year |
| 2020 | Available | Available | Available | |
| 2021 | Available + Sol2 | Available | Available | Alternate QR solution PDF (Sol2) also published |
| 2022 | Available | Available | Available | |
| 2023 | Available | Available | Available | |
| 2024 | Available | Available | Available | |
| 2025 | Available | Available | Available | Most recent complete cycle |
| 2026 | Not yet published at audit time | Check iaac.space after cycle completes | ||
All 46 accessible PDFs are image-based (scanned layouts). Download directly from iaac.space/docs/ — do not rely on third-party mirrors.
Both editions are built from official IAAC sources only — the flyer, the official presentation, and the seven-year past-paper archive. The Student Edition is a preparation playbook; the Advisor Edition adds the school-side logistics, the age-group framework, and the URL convention for the past-paper corpus.
These editions are Tian2 original work. Official IAAC problem PDFs are not reproduced here — download them from iaac.space/docs/. Unofficial; not affiliated with or endorsed by IAAC e.V.
Phase A — Foundations (weeks 1–4). Before touching a past paper, be comfortable with: spherical astronomy and coordinate systems (RA/Dec, hour angle, sidereal time); orbital mechanics and Kepler's three laws; stellar properties (magnitudes, distance modulus, H-R diagram, Stefan-Boltzmann, Wien); basic cosmology (Hubble's law, the cosmic distance ladder); and the math toolkit (logarithms, small-angle approximation, unit manipulation). No university-level calculus is required for the QR, but PFR and FR reward it.
Phase B — Past-paper drill (weeks 5–9). This is the highest-leverage phase. The archive gives you 42 official PDFs (7 years × 3 rounds × problems + solutions). Suggested rhythm: one full QR timed per week, one PFR untimed every two weeks, one FR problem attempted every three weeks. Rule: do not look at the solution until you have written down everything you would submit in a real attempt.
Phase C — Targeted weaknesses (weeks 10–11). Use your past-paper record to identify the two or three topics where you most consistently failed. Spend these weeks on those topics only. Optional: read one recent astronomy or astrophysics research article carefully — this is direct preparation for the PFR's research-problem format.
Phase D — Final-week polish (week 12). Review your own past-paper notebook, not new material. Hardware and quiet-space check — the competition is at home, online.
The QR is accessible without calculus. The PFR and FR reward short derivations, dimensional analysis, and comfort with orders of magnitude. Reading a real research abstract and extracting a number from it is a PFR-specific skill worth practising once.
Unofficial; not affiliated with or endorsed by IAAC e.V. or any competition body. Tian2 editions are original editorial work; original exam questions and official PDFs remain copyright their respective owners. Download all past papers from iaac.space/docs/ directly.
