INAO: syllabus, mock tests and practice
Indian National Astronomy Olympiad — Stage 2 of India's Science Olympiad programme in Astronomy, conducted by HBCSE. Top scorers qualify for the Orientation-cum-Selection Camp (OCSC), from which 5 students are chosen to represent India at the International Olympiad on Astronomy and Astrophysics (IOAA). For students in Class X, XI and XII.
- Classes
- Grade 9, Grade 10, Grade 11, Grade 12
- Syllabus years
- 2026-27
- Mock tests
- 19
- Downloads
- 34
About the INAO exam
How the exam works
INAO is the national second-stage Astronomy Olympiad. Entry comes through NSEA qualification and any officially permitted exemptions. HBCSE administers this stage; qualifying students may proceed to the Orientation-cum-Selection Camp and later team selection. The announced 2027 examination lasts three hours.
Who can apply
The IAPT 2026–27 portal lists Senior Science birth dates 1 July 2007–30 June 2012 and Classes 10–12, subject to the full current eligibility rules. For INO, the official brochure's nationality/residency, school and university conditions and any later amendments also apply. An age/class match alone does not guarantee eligibility.
When it happens
NSEA: 21 November 2026, 14:30–16:30 IST. INAO: 30 January 2027, 09:00–12:00 IST. HBCSE says senior INO selection lists will be published by 15 January 2027, followed by mandatory HBCSE registration. NSE enrolment for this cycle is closed. Checked 1 November 2026.
How to register
For the NSE stage, register through an approved centre or IAPT's self-enrolment portal during the published window; the 2026 fee was ₹300 per subject. Keep personal/parent details, school details and valid identity proof ready. This cycle's entry window is closed. Shortlisted senior candidates must register separately on HBCSE's INO site after the selection list; failure to register can disqualify an otherwise selected student.
Official website, syllabus and past papers
Senior science syllabuses broadly extend through CBSE Class 12, with supporting mathematics. Astronomy emphasises physics, mathematics and elementary astronomy. Include foundational material from earlier classes.
INAO syllabus
INAO syllabus, All classes · 2026-27
Physics (Class 12 level)
- Units, Measurements and Dimensions: Learn SI units, errors, significant figures and dimensional analysis, and use them to check physics results.
- Kinematics: Motion in a Line and in a Plane: Study position, velocity and acceleration graphs, vectors, relative velocity, projectile motion and uniform circular motion.
- Laws of Motion and Friction: Apply Newton's laws, momentum, impulse, friction and circular dynamics to solve problems.
- Work, Energy, Power and Collisions: Use work, kinetic and potential energy, conservation of energy and elastic and inelastic collisions.
- Rotational Motion and Centre of Mass: Study the centre of mass, torque, angular momentum, moment of inertia and equilibrium of rigid bodies.
- Mechanical Properties of Solids and Fluids: Study elasticity, Hooke's law, fluid pressure, Pascal's law, viscosity, surface tension and Bernoulli's theorem.
- Thermal Properties and Thermodynamics: Learn heat, temperature, calorimetry, heat transfer, laws of thermodynamics and heat engines.
- Oscillations and Waves: Study simple harmonic motion, the pendulum, resonance, travelling and standing waves, beats and the Doppler effect.
- Electrostatics and Capacitors: Learn Coulomb's law, electric field, Gauss's theorem, potential, dielectrics and capacitors.
- Current Electricity: Study Ohm's law, resistivity, cells, Kirchhoff's laws, bridge circuits and the potentiometer.
- Magnetic Effects of Current and Magnetism: Learn magnetic force on charges and currents, Biot-Savart and Ampere's laws, magnetic dipoles and magnetic materials.
- Electromagnetic Induction and Alternating Current: Study Faraday's and Lenz's laws, self and mutual induction, AC circuits, resonance, generators and transformers.
- Electromagnetic Waves and Ray Optics: Learn the electromagnetic spectrum, reflection, refraction, lenses, prisms and optical instruments.
- Wave Optics: Study interference, diffraction, polarisation and Huygens' principle.
- Dual Nature, Atoms, Nuclei and Semiconductors: Study the photoelectric effect, matter waves, Bohr's atom, radioactivity, nuclear energy and semiconductor diodes.
Mathematics (Class 12 level)
- Sets, Relations and Functions: Work with sets, relations and functions, including inverse functions and graphs.
- Trigonometric and Inverse Trigonometric Functions: Use trigonometric functions, identities, equations and inverse trigonometric functions.
- Complex Numbers, Quadratic Equations and Inequalities: Study complex numbers, quadratic equations and linear inequalities.
- Induction, Permutations, Combinations and Binomial Theorem: Use mathematical induction, counting rules, permutations, combinations and the binomial theorem.
- Sequences and Series: Work with arithmetic, geometric and other sequences and their sums.
- Matrices and Determinants: Learn matrix operations, determinants, inverses and solving linear systems.
- Straight Lines, Conic Sections and 3D Geometry: Study straight lines, circles, parabola, ellipse, hyperbola and an introduction to three-dimensional geometry.
- Limits, Continuity and Differentiability: Learn limits, continuity and derivatives of standard functions.
- Applications of Derivatives: Use derivatives for rates of change, tangents, increasing and decreasing functions and maxima and minima.
- Integrals and Their Applications: Learn methods of integration, definite integrals and areas under curves.
- Differential Equations: Form and solve simple first-order differential equations.
- Vectors and Three-Dimensional Geometry: Use vector algebra, dot and cross products, lines and planes in space.
- Statistics and Probability: Study measures of dispersion, probability, conditional probability and distributions.
- Mathematical Reasoning and Linear Programming: Learn logical statements and proofs, and solve simple linear programming problems.
Astronomy Applications of Physics
- Mechanics, Gravitation and Orbits: Use Newton's laws, work and energy, and the universal law of gravitation. Study escape and orbital velocity, satellites and the two-body problem.
- Kepler's Laws and Planetary Motion: Learn Kepler's three laws for circular and elliptical orbits, eccentricity and orbital period. Apply them to planets, moons and binary systems.
- Heat, Radiation and Thermodynamics: Study temperature, heat transfer, black-body radiation, Wien's displacement law and Stefan's law. Link these ideas to the temperature and luminosity of stars.
- Atomic Physics and Spectra: Learn Bohr's model, energy levels, the hydrogen spectrum and the photoelectric effect. Understand how spectra reveal what stars are made of.
- Nuclear Physics and Stellar Energy: Study radioactivity, binding energy, fission and fusion. Understand in simple terms how fusion powers the Sun and stars.
- Fluids and Kinetic Theory of Gases: Use pressure, buoyancy and the ideal gas law to understand planetary atmospheres, stellar gas and the Sun's layers.
Astronomy Applications of Mathematics
- Trigonometry and Spherical Geometry: Learn basic spherical geometry and spherical triangles. Use them to find angles, distances and positions on the celestial sphere.
- Ellipses and Orbit Geometry: Study the ellipse in detail: foci, semi-major axis, eccentricity and area. Use it to describe planetary and satellite orbits.
- Logarithms, Approximations and Estimation: Work with logarithms, powers of ten, small-angle approximations and order-of-magnitude estimates. Apply them to magnitudes, distances and sizes.
- Calculus and Vectors for Orbits and Motion: Apply derivatives, integrals and vectors to velocity, acceleration, angular momentum and energy in orbital motion.
Elementary Astronomy
- Celestial Sphere and Coordinate Systems: Learn the celestial sphere, poles, equator and the horizontal, equatorial and ecliptic coordinate systems. Study circumpolar stars, equinoxes and solstices.
- Time and the Calendar: Understand solar and sidereal time, the day and year, time zones and the equation of time. Link them to Earth's rotation and revolution.
- The Solar System: Study the Sun, planets, moons, asteroids, comets and meteoroids. Learn phases of the Moon, eclipses, tides and planetary motion.
- The Sun and Stellar Structure: Study the Sun's layers, sunspots and energy output. Learn the basic structure of a star and the balance between gravity and pressure.
- Stellar Magnitudes, Distances and Parallax: Learn apparent and absolute magnitude, luminosity, the distance modulus and parallax. Practise comparing the brightness and distance of stars.
- Stellar Spectra and the HR Diagram: Study spectral classes, the Hertzsprung-Russell diagram and the life cycle of stars. Include white dwarfs, neutron stars and black holes at an elementary level.
- Binary and Variable Stars: Learn visual and eclipsing binaries, how their masses are found, and common variable stars such as Cepheids.
- Telescopes and Detectors: Compare refracting, reflecting and radio telescopes. Study magnification, aperture, resolving power and diffraction limits, common detectors, and why astronomers observe across the electromagnetic spectrum.
- The Milky Way and Galaxies: Study the structure of our galaxy, the types of galaxies, clusters and the distance ladder.
- Cosmology: The Expanding Universe: Learn redshift, Hubble's law, the Big Bang, the cosmic microwave background and the idea of dark matter and dark energy.
- Night Sky Observation: Practise reading star charts, spotting constellations and bright stars, and estimating angular separations and magnitudes by eye.
- History of Astronomy: Learn the major landmarks in the development of astronomy, from ancient observers to Copernicus, Galileo, Kepler and Newton and modern space telescopes.
Rounds and levels
- 2026-27: Practice for INAO 2026-27 (exam date: 30 January 2027).
- Previous-year papers: Past INAO question papers.
More exams on SkillStar
INAO: questions parents ask
- Which classes can prepare for INAO on SkillStar?
- INAO practice on SkillStar is arranged for Grade 9, Grade 10, Grade 11 and Grade 12. Each child sees what's right for their own class.
- What is in the INAO syllabus for 2026-27?
- 51 topics in Physics (Class 12 level), Mathematics (Class 12 level), Astronomy Applications of Physics, Astronomy Applications of Mathematics and Elementary Astronomy, laid out subject by subject on this page. On SkillStar your child can tick off each topic as they learn it.
- Are there INAO mock tests on SkillStar?
- Yes, 19 mock tests. Each one is marked the moment your child finishes, with a question-by-question review, and can be taken again as often as they like.
- Can I download INAO papers?
- Yes. The INAO Downloads tab on SkillStar has 34 files for this exam.
- How does my child start INAO practice?
- Sign up free as a parent, add your child with their class, and pick INAO from the exam list. Every new family gets welcome credits, lots of content costs nothing, and anything paid shows its price in credits before you decide.
- Is SkillStar the official INAO website?
- No. SkillStar is an independent practice platform and is not affiliated with, or endorsed by, the organisers of these exams. Exam names belong to their respective owners. Check dates, fees and registration with the INAO organisers.
SkillStar is an independent practice platform and is not affiliated with, or endorsed by, the organisers of these exams. Exam names belong to their respective owners.