An astronomer is someone who studies the universe. For example
they study Earth, solar system and the galaxies.
A astronomer is a person who studies the subject of astronomy,
the branch of physics relating to celestial bodies and the universe
as a whole.
A scientist who studies stars as a career is called an
If he specialises in the physics of the stars, he would be an
A person who studies the stars is called an astronomer. They
partake in the branch of study that is called astronomy.