I'm studying to become an astronomer.
I am an astronomer.
Carl Sagan was a noted astronomer.
The astronomer studied distant galaxies using a powerful telescope.
Traditionally, an astronomer directly observed the stars, but nowadays some astronomers instead use data automatically generated by properly programmed telescopes or satellites.
The astronomer's observations proved that cephid variable stars would pulsate in a regular cycle
The astronomer looked through the telescope's eyepiece to observe the stars.
The astronomical star looked like it could be a planet because of its enormous size.
Astronomer's are people (scientists) who study celestial bodies. So by profession an astronomer uses a telescope and not a microscope.
"I logged onto WikiAnswers, went directly to the Astronomy category, and immediately chanced upon a new question that challenged: 'Use refracting telescope in a sentence' . "
Galieo was the first astronomer to view Jupiter's moons through a telescope and proved the heliocentric model.
A telescope is the instrument an astronomer uses to study matter in space.
A clock