Preparation

What to Study

The CAAO Tutorial is introductory preparation for the national examination. Use this guide alongside past papers and the instructions for your competition year.

CAAO Tutorial — Armin Hodaei, 2025

The tutorial introduces the main topics and works through examples.

Download the CAAO Tutorial (PDF)

Reading map

  1. Chapter 1: astronomical distance, luminosity, flux and magnitudes.
  2. Chapter 2: telescope optics and resolving power.
  3. Chapter 3: stars, galaxies, redshift and planetary motion.
  4. Chapter 4: spherical geometry and celestial coordinates.
  5. Chapter 5: gravity, momentum and orbital mechanics.
  6. Chapter 6: practice problems.
  7. Appendix A: mathematical reference.

How to prepare

Study one topic at a time, then attempt related past CAAO problems independently. Show your reasoning, use appropriate units, and revisit mistakes. Use papers from your intended division to become familiar with the questions. When the 2027 writing duration and permitted resources are published, practise under those conditions.

Junior past papersSenior past papersHow to Participate

Further reading and videos

Problems already on this site

IOAA problems by topic through 2013 (PDF)

Textbooks

  1. Foundations of Astrophysics by Barbara Ryden
  2. Fundamental Astronomy by Karttunen et. al.
  3. An Introduction to Modern Astrophysics by Bradley Carroll and Dale Ostlie
  4. Astronomy Principles and Practice by Archie E. Roy and David Clarke
  5. Introduction to Cosmology by Barbara Ryden

Video lectures

International preparation