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.

2026

Paper 180 min → Problems Solutions

Problem 1 (12 pts)

Galileo's Observations

Problem 2 (10 pts)

Stars in Nashik

Problem 3 (30 pts)

Approximating π

Problem 4 (8 pts)

Blackbody Radiation

Problem 5 (10 pts)

Observing the ISS

Problem 6 (30 pts)

Planet's Orbit around a Binary Star

2025

Paper 180 min → Problems Solutions 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

Paper 180 min → Problems Solutions 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

Paper 180 min → Problems 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

Paper 180 min → Problems 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

Paper 180 min → Problems 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

Paper 180 min → Problems 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

Paper 180 min → 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

Paper 180 min → Problems 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

Paper 180 min → Problems 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

Paper 180 min → Problems 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

Paper 180 min → Problems Solutions

2011

Paper 180 min → Problems Solutions

2010

Junior 180 min → Junior Problems Junior Solutions Senior 180 min → Senior Problems Senior Solutions

2009

Junior 180 min → Junior Problems Junior Solutions Senior 180 min → Senior Problems Senior Solutions