IOAA Problems and Solutions

First held in Chiang Mai in 2007 with 22 countries. It runs more rounds than any other olympiad here: theory, data analysis, and observation both under the sky and in a planetarium.

2025

India

Theory12 problemsProblemsSolutions
  • 1Daksha Missionnot published
  • 2Makar-Sankrantinot published
  • 3Gravitational Wavesnot published
  • 4Balmer Decrementnot published
  • 5Quasarsnot published
  • 6Galactic Rotationnot published
  • 7Neutron Star Binarynot published
  • 8Shadow of a black holenot published
  • 9Atmospheric Seeingnot published
  • 10Big Bang Nucleosynthesisnot published
  • 11Stars through graphsnot published
  • 12Hawking Radiation from Black Holesnot published
Data Analysis2 problemsProblemsSolutions
  • 1330 Years of Exoplanetsnot published
  • 14Predicting arrival times of coronal mass ejectionsnot published
Observation (Planetarium)2 problemsProblemsSolutions
  • 15Hypothesized Planet in the Solar Systemnot published
  • 16Observer on a Ringed Planetnot published
Observation (Sky Map)3 problemsProblemsSolutions
  • 17Know your Skynot published
  • 18Know your Gridnot published
  • 19Know your Timenot published
Observation (Telescope)2 problemsProblemsSolutions
  • 20Discovery of 'Z'not published
  • 21Lensing Time Delaynot published

2024

Brazil

Theory11 problemsProblemsSolutions
  • 1Sundialnot published
  • 2Galaxy Clusternot published
  • 3Asteroidnot published
  • 4White Dwarfnot published
  • 5Cmbnot published
  • 6Cluster Photographynot published
  • 7Castawaynot published
  • 8Binary Hardeningnot published
  • 9Physics of Accretionnot published
  • 10Greatest Eclipsenot published
  • 11Ground Tracksnot published
Data Analysis2 problemsProblemsSolutions
  • 12Photometric comparison of surveysnot published
  • 13Shapley Hypothesisnot published
Observation3 problemsProblemsSolutions
Observation (Planetarium)2 problemsProblemsSolutions

2023

Poland

Theory5 problemsProblemsSolutions
  • 1Neptunenot published
  • 2Magnetic fieldnot published
  • 3Microlensingnot published
  • 4Europanot published
  • 5Dark Energynot published
Theory5 problemsProblemsSolutions
  • 6Bolometernot published
  • 7Librationnot published
  • 8Neutrinosnot published
  • 9Second eclipsenot published
  • 10Aldebarannot published
Theory3 problemsProblemsSolutions
  • 11X-ray emission from galaxy clustersnot published
  • 12Dartnot published
  • 13Lisanot published
Data Analysis2 problemsProblemsSolutions
  • 14Distance to the Large Magellanic Cloudnot published
  • 15Isolated black holenot published
Observation4 problemsProblemsSolutions
  • 16Asteroid occultationnot published
  • 17Starlinknot published
  • 18Planetary Moonsnot published
  • 19Supernovanot published
Observation (Planetarium)3 problemsProblemsSolutions
  • 20Knowledge of the skynot published
  • 21Retrograde Marsnot published
  • 22TRAPPIST-1not published

2022

Georgia

Theory13 problemsProblemsSolutions
  • 1Planck's unitsnot published
  • 2Circumbinary planetnot published
  • 3Expanding ring nebulanot published
  • 4Journey Between Galaxiesnot published
  • 5Flaring protoplanetary disknot published
  • 6Photometry of Binary starsnot published
  • 7Georgia to Georgianot published
  • 8Ring of a planetnot published
  • 9Solar Retrograde Motion on Mercurynot published
  • 10Accretionnot published
  • 11Dyson Spherenot published
  • 12Co-orbital satellitesnot published
  • 13Relativistic Beamingnot published
Data Analysis2 problemsProblems
Observation (Night)4 problemsProblemsSolutions
  • 16Observation 1not published
  • 17Observation 2not published
  • 18Observation 3not published
  • 19Observation 4not published
Observation (Day)5 problemsProblemsSolutions
  • 20Observation 5not published
  • 21Observation 6not published
  • 22Observation 7not published
  • 23Observation 8not published
  • 24Observation 9not published

2021

Colombia

Theory13 problemsProblemsSolutions
  • 1LIGOnot published
  • 2Temperature of the Earthnot published
  • 3Marsnot published
  • 4Alma - Calculating photonsnot published
  • 5Under pressurenot published
  • 6Macondo and Melquiadesnot published
  • 7Menkalinan (beta Aurigae)not published
  • 8Ioaa Logonot published
  • 9Pluto Satellitesnot published
  • 10Terrestrial Transitnot published
  • 11Minimum velocity of a projectilenot published
  • 12Hodographnot published
  • 13Lucy: The First Mission to the Trojan Asteroidsnot published
Problems4 problems

2019

Hungary

Theory14 problemsProblemsSolutions
  • 1Famous astronomical eventsnot published
  • 2Deflection of radio photons in the gravitational field of solar system bodiesnot published
  • 3The supermassive black hole in the centre of Milky Way Galaxy and M87not published
  • 4Improving a common reflecting telescopenot published
  • 5Cosmic Microwave Background Ovennot published
  • 6The height of the chimney of Tiszaujvaros power plantnot published
  • 7Effect of sunspots on solar irradiancenot published
  • 8Amplitude variation of rr Lyrae starsnot published
  • 9Distance of the Lagrangian point L2 of the Earth-Moon systemnot published
  • 10South to East to Northnot published
  • 11Identification of light curves of types of selected variable starsnot published
  • 12Distance to a Near-Earth Asteroidnot published
  • 13Distance to the Coma galaxy clusternot published
  • 14Photographing a nanosatellitenot published
Data Analysis2 problemsProblemsSolutions
  • 15Photometry and spectroscopy of Nova Del 2013not published
  • 16Triply eclipsing hierarchical triple stellar systemnot published
Observation5 problemsProblemsSolutions
  • 17Finderscope alignmentnot published
  • 18Observation of Saturnnot published
  • 19M57 - field of viewnot published
  • 20Variable star - af Cygninot published
  • 21Naked eye brightness estimationnot published
Observation (Planetarium)3 problemsProblemsSolutions

2018

China

Theory11 problemsProblemsSolutions
  • 1Super Luminal Galaxiesnot published
  • 2Distancenot published
  • 3Atmospheric Refractionnot published
  • 4Height of a Hillnot published
  • 5Sidereal Timenot published
  • 6Observe the Sun with fastnot published
  • 7Sunspotnot published
  • 8A Possible Dark Matter Deficient Galaxynot published
  • 9Radio Galaxynot published
  • 10Vega and Altairnot published
  • 11Thermal History of the Universenot published
Data Analysis2 problemsProblemsSolutions
  • 12Dust and Young Stars in Star-forming Galaxiesnot published
  • 13Compact Object in a Binary Systemnot published
Observation4 problemsProblemsSolutions
Observation2 problemsProblemsSolutions

2017

Thailand

Theory13 problemsProblemsSolutions
  • 1The Large Magellanic Cloud in Phuketnot published
  • 2Earth's Transit Zonenot published
  • 3The Milky Way's Distant Outer Armnot published
  • 421-cm hi galaxy surveynot published
  • 5A Synchronous Satellitenot published
  • 6Supernova 1987Anot published
  • 7Life on Other Planetsnot published
  • 8The Star of Bethlehemnot published
  • 9Galactic Outflownot published
  • 10Gotonot published
  • 11Mass of the Local Groupnot published
  • 12Shipwrecknot published
  • 13Exomoonnot published
Data Analysis2 problemsProblemsSolutions
  • 14Calibrating the distance ladder to the lmcnot published
  • 15The search for dark matternot published
Observation (Day) P7 problemsProblems
  • 16Naked eye observation from real skynot published
  • 17Planet observation with real sky in panoramic 360-degree imagenot published
  • 18Analemma on another planetnot published
  • 19Exposure time from a Photographnot published
  • 20Find True North from Moon shadownot published
  • 21Find Latitude from Equatorial Mountnot published
  • 22Precision Polar Alignment with Equatorial Mountnot published
Observation (Night) N2 problemsProblems
  • 23Observation with Equatorial Mount Telescopenot published
  • 24Observation with Dobsonian Telescopenot published

2016

India

Theory12 problemsProblemsSolutions
  • 1True or Falsenot published
  • 2Gases on Titannot published
  • 3Early Universenot published
  • 4Shadowsnot published
  • 5Gmrt beam transitnot published
  • 6Cepheid Pulsationsnot published
  • 7Telescope opticsnot published
  • 8U-Band photometrynot published
  • 9Mars Orbiter Missionnot published
  • 10Gravitational Lensing Telescopenot published
  • 11Gravitational Wavesnot published
  • 12AstroSatnot published
Data Analysis3 problemsProblemsSolutions
  • 13Binary Pulsarnot published
  • 14Distance to the Moonnot published
  • 15Type ia Supernovaenot published
Problems5 problemsProblems
  • 16Observation (Telescope) OT1not published
  • 17Observation (Telescope) OT2not published
  • 18Observation (Telescope) OT3not published
  • 19Observation (Planetarium) OP1not published
  • 20Observation (Planetarium) OP2not published

2014

Romania

Theory Short12 problemsProblemsSolutions
  • 1Lagrange Pointsnot published
  • 2Sun gravitational catastrophe!not published
  • 3Cosmic radiationnot published
  • 4Sandra Bullock And George Cloonynot published
  • 5The life-time of a main sequence starnot published
  • 6The effective temperature of a starnot published
  • 7Pressure of lightnot published
  • 8Space-ship orbiting the Sunnot published
  • 9The Vega star in the mirrornot published
  • 10Stars with Romanian namesnot published
  • 11Apparent magnitude of the Moonnot published
  • 12Absolute magnitude of a cepheidnot published
Theory Long2 problemsProblemsSolutions
  • 13Eagles on the Caraiman Cross!not published
  • 14From Romania to Antipod! With a ballistic messengernot published
Data Analysis3 problemsProblemsSolutions
  • 15Black Hole in Milky Waynot published
  • 16Thermodynamic testnot published
  • 17Ioaa Observer on an extrasolar planetnot published
Observation (Outdoor)7 problemsProblems
Observation (Planetarium)3 problemsProblemsSolutions

2010

China

Theory15 problemsProblemsSolutions
Theory2 problemsProblemsSolutions
Problems2 problemsProblemsSolutions
  • 18Data Analysis I: Ccd imagenot published
  • 19Data Analysis ii: Light curves of starsnot published
Problems6 problemsProblemsSolutions
  • 20Observation (Telescope) 1not published
  • 21Observation (Telescope) 2not published
  • 22Observation (Telescope) 3not published
  • 23Observation (Planetarium) 1not published
  • 24Observation (Planetarium) 2not published
  • 25Observation (Planetarium) 3not published

2007

Thailand

Problems18 problemsProblemsSolutions
  • 1Theory 1.1not published
  • 2Theory 1.2not published
  • 3Theory 1.3not published
  • 4Theory 1.4not published
  • 5Theory 1.5not published
  • 6Theory 1.6not published
  • 7Theory 1.7not published
  • 8Theory 1.8not published
  • 9Theory 1.9not published
  • 10Theory 1.10not published
  • 11Theory 1.11not published
  • 12Theory 1.12not published
  • 13Theory 1.13not published
  • 14Theory 1.14not published
  • 15Theory 1.15not published
  • 16Theory 2: A Planet and Its Surface Temperaturenot published
  • 17Theory 3: Binary Systemnot published
  • 18Theory 4: Gravitational Lensingnot published
Data Analysis3 problemsProblemsSolutions
  • 19Galilean moonsnot published
  • 20The Moon's agenot published
  • 21Solar System objectsnot published
Problems2 problemsProblemsSolutions
  • 22Observation Part I: Celestial object pointernot published
  • 23Observation Part ii: Binocularsnot published