The astronomer conducted an observation of the night sky.

He likes to observe celestial bodies.

He is world-famous as an astronomer.

He is a famous author and a person who is respected by many people.

The stars were twinkling in the night sky.

This festival is held every year.

He used a stick to measure the depth of the river.

He measured the size of the room.

He understood the meaning of '觀' written in old characters.

He has a deep interest in astronomy.