USAAAO Problems and Solutions
The olympiad that picks the US team for the IOAA: an online First Round, then the National Astronomy Championship, and in 2026 a third exam with theory and practical papers. Here are the papers from 2014 to 2026, most with their solutions.
2026
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2026 First Round problem 1, All problems National Astronomy Championship
1 A "gravitational atom" not published 2 Celestial Sphere: Night at the Observatory not published 3 Sky Map Attack! not published USAAAO 2026 National Astronomy Championship problem 3, Sky Map Attack! 4 Solar Observatory not published 5 Enceladus Geysers not published 6 Build your Own H-R Diagram not published USAAAO 2026 National Astronomy Championship problem 6, Build your Own H-R Diagram 7 Interstellar Flight not published 8 Watch Out! not published 9 Neutron Star Dynamics not published USAAAO 2026 National Astronomy Championship problem 9, Neutron Star Dynamics Third Exam
1 Problem T1 not published 2 Dubhe not published 3 Recession of the Moon not published 4 Stellar Odyssey not published 5 His Dark Materials not published 6 Type II Supernova not published 7 Travelers in Outer Space not published 8 Stars in the Telescope not published 9 Sky Map Attack 2! not published
2025
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2025 First Round problem 1, All problems National Astronomy Championship
1 Tracking a Bootes Planet not published 2 The Eye as a Camera not published 3 Sailing not published 4 Gravitational Waves not published 5 Stupendous Man's Saga not published 6 Spherical Cluster not published 7 Planetary Defense not published
2024
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2024 First Round problem 1, All problems National Astronomy Championship
1 The Boomerang Nebula not published 2 Gegenschein Dust not published 3 Stellar Dodecahedron not published 4 Solar Eclipse not published 5 Neutrino Decoupling not published 6 Spiff's Adventures not published 7 Tess not published 8 The Analemma not published
2023
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2023 First Round problem 1, All problems National Astronomy Championship
1 White Dwarfs not published 2 The Large Magellanic Cloud not published 3 Culmination Time not published 4 Hyperfine Splitting not published 5 Quantum Fusion not published 6 Into the Wilds not published 7 The Sundial II not published 8 Interstellar Comet not published 9 Finding Friends not published
2022
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2022 First Round problem 1, All problems National Astronomy Championship
1 Hydrogen Atom Energies not published 2 Binary Mass Function not published 3 Exoplanet Radius Transit not published 4 Posidonius Earth Measurement not published 5 Electron Orbital Energy not published 6 The Speed of Light not published 7 Meteorite Space Station not published 8 The Curious Orbit of James Webb not published 9 The Sundial I not published
2021
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2021 First Round problem 1, All problems National Astronomy Championship
1 Jupiter not published 2 Solar Interior not published 3 Seeing galaxies not published 4 Eccentric orbit not published 5 Winter sunset not published 6 Relativistic Clock not published 7 Hohmann Transfer not published 8 Space Station not published 9 Big Bang Nucleosynthesis not published 10 Conjunction not published
2020
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2020 First Round problem 1, All problems National Astronomy Championship
1 Quadrature not published 2 Betelgeuse not published 3 Lyman-Break not published 4 TRAPPIST-1d not published 5 Hd 209458b not published 6 Telescoping a binary not published 7 Galaxy Rotation Curves not published 8 Moon not published 9 Black Holes not published 10 Stellar Properties not published 11 M15 Cluster not published 12 Sunspot Magnetograms not published
2019
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2019 First Round problem 1, All problems National Astronomy Championship
1 Nucleosynthesis not published 2 Lunar Eclipse not published 3 Seeing stars not published 4 Pressure Gradient not published 5 Terrestrial Precession not published 6 Exoplanet detection not published 7 Minimal Black Holes not published 8 A weird universe not published 9 Finding distances not published 10 Magnetic Moments not published 11 Cygnus X-1 not published
2018
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2018 First Round problem 1, All problems National Astronomy Championship
Show all 14 problems 1 Problem S1 not published 2 Problem S2 not published 3 Problem S3 not published 4 Problem S4 not published 5 Problem S5 not published 6 Problem S6 not published 7 Problem S7 not published 8 Problem S8 not published 9 Problem S9 not published 10 Problem S10 not published 11 Problem S11 not published 12 WASP-14b not published 13 Sualocin and Rotanev not published 14 Fusing hydrogen not published
2017
USA
First Round
National Astronomy Championship
1 Problem 1 not published 2 Problem 2 not published 3 Problem 3 not published 4 Problem 4 not published 5 Problem 5 not published 6 Problem 6 not published 7 Problem 7 not published 8 Problem 8 not published 9 Problem 9 not published
2016
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2016 First Round problem 1, All problems National Astronomy Championship
Show all 14 problems 1 Problem 1 not published 2 Problem 2 not published 3 Problem 3 not published 4 Problem 4 not published 5 Problem 5 not published 6 Problem 6 not published 7 Problem 7 not published 8 Problem 8 not published 9 Problem 9 not published 10 Problem 10 not published 11 Problem 11 not published 12 Problem 12 not published 13 Problem L1 not published 14 Problem L2 not published
2015
USA
First Round
Problems 1 problem
1 All problems Problem Solution USAAAO 2015 First Round problem 1, All problems National Astronomy Championship
Show all 14 problems 1 Problem 1 not published 2 Problem 2 not published 3 Problem 3 not published 4 Problem 4 not published 5 Problem 5 not published 6 Problem 6 not published 7 Problem 7 not published 8 Problem 8 not published 9 Problem 9 not published 10 Problem 10 not published 11 Problem 11 not published 12 Problem 12 not published 13 Problem 13 not published 14 Problem L1 not published
2014
USA
National Astronomy Championship
Problems 1 problem
1 All problems Problem Solution USAAAO 2014 National Astronomy Championship problem 1, All problems
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