Indian National Astronomy Olympiad

The Indian National Astronomy Olympiad (INAO) is conducted by the Homi Bhabha Centre for Science Education (HBCSE) as part of the national science olympiad program. INAO serves as the primary selection mechanism for India's team to the International Olympiad on Astronomy and Astrophysics (IOAA). The competition tests theoretical knowledge, observational skills, and problem-solving abilities in astronomy and astrophysics. Top performers from INAO proceed to orientation camps and further selection rounds for international representation.

2025

General

General Problems General Solutions General Answer Sheet

Problem 1 (10 pts)

Solar Telescope

Problem 2 (15 pts)

Exoplanet Detection

Problem 3 (15 pts)

Venus Phases

Problem 4 (15 pts)

Star-Planet-Moon System

Problem 5 (7 pts)

HR Diagram

Problem 6 (8 pts)

Doppler Shifts

Problem 7 (5 pts)

Solar Sail

Problem 8 (5 pts)

Light Isodelay Surface

Problem 9 (5 pts)

Telluric Phases

Problem 10 (5 pts)

Sun at Horizon

Problem 11 (5 pts)

Spinning White Dwarf

Problem 12 (5 pts)

Redshift of Sirius B

2024

General

General Problems General Solutions General Answer Sheet

Problem 1 (23 pts)

Celestial Observations

Problem 2 (26 pts)

Binary Planets

Problem 3 (20 pts)

Liquid Transfer Equilibrium

Problem 4 (17 pts)

Telescope Alignment

Problem 5 (16 pts)

Celestial Coordinates

2023

General

General Problems General Solutions

Problem 1 (22 pts)

Hohmann Transfer Orbit

Problem 2 (10 pts)

Binary Star Resolution

Problem 3 (16 pts)

Thermal Equilibrium Box

Problem 4 (15 pts)

Asteroid Belt Collision

Problem 5 (22 pts)

Earth-Mars Orbital Motion

Problem 6 (17 pts)

Lunar North Pole

2020

General

General Problems General Solutions

Problem 1 (10 pts)

Mars Rise Time

Problem 2 (10 pts)

Rapunzel Hair Growth

Problem 3 (10 pts)

Circle Perimeter Grid

Problem 4 (18 pts)

Stellar Triangle System

Problem 5 (20 pts)

Cannonball Orbit

Problem 6 (12 pts)

Pulsar Properties

Problem 7 (20 pts)

Moon Crescent Image

2019

General

General Problems General Solutions

Problem 1 (12 pts)

Moon Phases

Problem 2 (10 pts)

Solar System Configurations

Problem 3 (20 pts)

Light Reduction Lens

Problem 4 (14 pts)

Star Constellation

Problem 5 (10 pts)

Earth Map Projections

Problem 6 (10 pts)

Heated Wire Cooling

Problem 7 (24 pts)

Tidal Height Modeling

2018

General

General Problems General Solutions

Problem 1 (5 pts)

Sun Angular Difference

Problem 2 (10 pts)

Bus Solar Power

Problem 3 (9 pts)

Kepler-13Ab Orbit

Problem 4 (15 pts)

Infinity Corridor

Problem 5 (15 pts)

Moon Rise Time

Problem 6 (17 pts)

Planets Observation

Problem 7 (18 pts)

Binary Star Orbit

Problem 8 (11 pts)

Telescope Mirror Segments

2017

General

General Solutions

Problem 1 (15 pts)

Astronomical Phenomena

Problem 2 (7 pts)

Shadow Geometry

Problem 3 (20 pts)

Supernova Flux

Problem 4 (8 pts)

Bus Station Schedule

Problem 5 (20 pts)

Alternate Refraction Laws

Problem 6 (15 pts)

Probability Problems

Problem 7 (15 pts)

Balloon Expansion

2016

General

General Problems General Solutions

Problem 1 (9 pts)

Constellation Identification

Problem 2 (12 pts)

Neptune Methane Energy

Problem 3 (10 pts)

Math Patterns

Problem 4 (10 pts)

Boat River Signboard

Problem 5 (6 pts)

Triple Lens System

Problem 6 (10 pts)

Meter Stick Shadow

Problem 7 (16 pts)

Doppler Whistle Rotation

Problem 8 (12 pts)

Ball Container Acoustics

Problem 9 (15 pts)

Stellar Magnitude Device

2015

General

General Problems General Solutions

Problem 1 (10 pts)

Wheat Food Staple

Problem 2 (10 pts)

Object Categories

Problem 3 (6 pts)

Satellite Orbital Periods

Problem 4 (15 pts)

True/False Statements

Problem 5 (7 pts)

Ants Shortest Path

Problem 6 (6 pts)

Light Ray Mirrors

Problem 7 (8 pts)

Proton Beam Magnetic

Problem 8 (8 pts)

Geostationary Satellites

Problem 9 (4 pts)

Exoplanet Catalogue

2014

General

General Problems General Solutions

Problem 1 (12 pts)

Moon Landing

Problem 2 (6 pts)

Comet Distance

Problem 3 (14 pts)

Aircraft Speed

Problem 4 (15 pts)

Skymap Markings

Problem 5 (12 pts)

Gliese-876 Planet

Problem 6 (15 pts)

Lens Mirror Overlap

Problem 7 (8 pts)

Chandrayaan Gold Wire

Problem 8 (18 pts)

Voyager Unknown Object

2012

General

General Problems General Solutions

Problem 1 (3 pts)

Universe Age

Problem 2 (3 pts)

Exponential Function

Problem 3 (3 pts)

Floating Container

Problem 4 (3 pts)

Electron Motion

Problem 5 (3 pts)

Pinhole Sun Image

Problem 6 (3 pts)

Rocket Launch

Problem 7 (3 pts)

Car Velocity

Problem 8 (3 pts)

Sunset Atmosphere

Problem 9 (3 pts)

Tennis Tournament

Problem 10 (3 pts)

Heat Transfer

Problem 11 (5 pts)

Constellation Statements

Problem 12 (5 pts)

Magnetic Pendulum

Problem α (10 pts)

Constellation List

Problem β (12 pts)

Polynomial Orbit

Problem γ (12 pts)

Hollow Earth Gravity

Problem δ (12 pts)

Black Cloud

Problem ε (12 pts)

Asteroid Deviation

2011

General

General Problems General Solutions

Problem 1 (3 pts)

Polar Satellite

Problem 2 (3 pts)

Potential Energy

Problem 3 (3 pts)

Pole Star

Problem 4 (3 pts)

Converging Lenses

Problem 5 (3 pts)

Ring Falling

Problem 6 (3 pts)

Charged Particle

Problem 7 (3 pts)

Number Puzzle

Problem 8 (3 pts)

P-V Diagram

Problem 9 (3 pts)

Equivalent Resistance

Problem 10 (3 pts)

Prime Numbers

Problem 11 (5 pts)

Proton Equilibrium

Problem 12 (5 pts)

Charge Distribution

Problem 13 (5 pts)

Block Friction

Problem 14 (5 pts)

Star Brightness

Problem α (8 pts)

Star Constellation

Problem β (8 pts)

Chandrasekhar Mass

Problem γ (8 pts)

Solar Plasma Cone

Problem δ (8 pts)

Star Temperature

Problem ε (9 pts)

DTH Antenna

Problem ζ (9 pts)

Graph Sketching

2010

General

Junior Problems Junior Solutions Senior Problems Senior Solutions

Problem 1 (3 pts)

Stellar Twinkling Junior

Problem 2 (3 pts)

Unpainted Cubes Junior

Problem 3 (3 pts)

Double-Painted Cubes Junior

Problem 4 (3 pts)

Corner Cube Cutting Junior

Problem 5 (3 pts)

Watch Time Drift Junior

Problem 6 (3 pts)

Parallel Current Wires Junior

Problem 7 (3 pts)

Magnifying Glass Junior

Problem 8 (3 pts)

Earthquake Distance Junior

Problem 9 (3 pts)

Escalator Steps Junior

Problem 10 (3 pts)

Binary Stars Junior

Problem 11 (5 pts)

Ripple Propagation Junior

Problem 12 (5 pts)

Cannon Ball Jets Junior

Problem 13 (5 pts)

Astronomy History Junior

Problem 14 (5 pts)

Pendulum Coplanarity Junior

Problem α (10 pts)

Alien Code Junior

Problem β (8 pts)

Optical Phenomena Junior

Problem γ (10 pts)

Night Sky Analysis Junior

Problem δ (10 pts)

Latitude Shadow Junior

Problem ε (12 pts)

Graph Sketching Junior

Problem 1 (3 pts)

Stellar Twinkling Senior

Problem 2 (3 pts)

Unpainted Cubes Senior

Problem 3 (3 pts)

Double-Painted Cubes Senior

Problem 4 (3 pts)

Corner Cube Cutting Senior

Problem 5 (3 pts)

Bicycle Balance Senior

Problem 6 (3 pts)

Sonic Boom Altitude Senior

Problem 7 (3 pts)

Magnifying Glass Senior

Problem 8 (3 pts)

Earthquake Distance Senior

Problem 9 (3 pts)

Escalator Steps Senior

Problem 10 (3 pts)

Binary Stars Senior

Problem 11 (5 pts)

Ripple Propagation Senior

Problem 12 (5 pts)

Cannon Ball Jets Senior

Problem 13 (5 pts)

Astronomy History Senior

Problem 14 (5 pts)

Pendulum Coplanarity Senior

Problem α (10 pts)

Alien Code Senior

Problem β (8 pts)

Optical Phenomena Senior

Problem γ (10 pts)

Night Sky Analysis Senior

Problem δ (10 pts)

Latitude Shadow Senior

Problem ε (12 pts)

Graph Sketching Senior

2009

General

Junior Problems Junior Solutions Senior Problems Senior Solutions

Problem 1 (3 pts)

Algebraic Expression Junior

Problem 2 (3 pts)

Constellation Pattern Junior

Problem 3 (3 pts)

Gold Sphere Gravity Junior

Problem 4 (3 pts)

Thermal Conductivity Junior

Problem 5 (3 pts)

Number Divisibility Junior

Problem 6 (3 pts)

Free Fall Physics Junior

Problem 7 (3 pts)

Solar Geometry Junior

Problem 8 (3 pts)

Light Shadow Junior

Problem 9 (3 pts)

Speed-Time Graph Junior

Problem 10 (3 pts)

Fluid Mechanics Junior

Problem 11 (5 pts)

Energy Systems Junior

Problem 12 (5 pts)

Radioactive Dating Junior

Problem 13 (5 pts)

Travel Kinematics Junior

Problem 14 (5 pts)

Cosmic Measurement Junior

Problem α (8 pts)

Inscribed Quadrilateral Junior

Problem β (12 pts)

Eclipse Geometry Junior

Problem γ (8 pts)

Aryabhata Pi Value Junior

Problem δ (12 pts)

Electrical Resistance Junior

Problem ε (10 pts)

Surface Area Junior

Problem 1 (3 pts)

Algebraic Expression Senior

Problem 2 (3 pts)

Constellation Pattern Senior

Problem 3 (3 pts)

Gold Sphere Gravity Senior

Problem 4 (3 pts)

Thermal Conductivity Senior

Problem 5 (3 pts)

Number Divisibility Senior

Problem 6 (3 pts)

Vector Mathematics Senior

Problem 7 (3 pts)

Lunar Orbit Senior

Problem 8 (3 pts)

Light Shadow Senior

Problem 9 (3 pts)

Celestial Navigation Senior

Problem 10 (3 pts)

Optical Lens Senior

Problem 11 (5 pts)

Energy Systems Senior

Problem 12 (5 pts)

Thermodynamics Process Senior

Problem 13 (5 pts)

Radioactive Dating Senior

Problem 14 (5 pts)

Distance Estimation Senior

Problem α (8 pts)

Inscribed Quadrilateral Senior

Problem β (12 pts)

Eclipse Geometry Senior

Problem γ (8 pts)

Aryabhata Pi Value Senior

Problem δ (10 pts)

3D Packing Geometry Senior

Problem ε (10 pts)

Pendulum g Value Senior