The Online Astronomy Competition (OAC) is a free, international astronomy competition for high school students. Our mission is to make astronomy accessible and exciting for students everywhere, regardless of background or location. The OAC is conducted entirely online and is open to all eligible students at no cost.

The competition consists of two rounds:

• 1. First Round (September 21, 2025): Open to all eligible students. This round features multiple-choice and short-answer questions covering a wide range of astronomy topics.
• 2. Second Round (October 4, 2025): Top performers from Round 1 are invited. This round is subjective and consists of olympiad-style, open-ended problems that require deeper understanding and creative thinking.

All rounds are conducted online, so you can participate from anywhere in the world.

Eligibility:

Registration: