Astronomers
Anything outside the Earth is astronomy.
the Greeks called the planets wanderers
Using the stars (and planets) to predict future events on Earth is called Astrology. There aren't many who would still call it a "science," though.
Physiologists
There is a science and a related non-scientific practice:An astronomer is a scientist who observes stars, planets, and other phenomena.An astrologer is a person who determines traits and predicts individual horoscopes based on the positions of the Sun, Moon, stars, and planets.
Anything outside the Earth is astronomy.
You don't.
exoplanets
A huge mass of stars and planets is called a galaxy.
An astronomer.
Technically yes. A long time ago, when people didn't know about planets, they called the ones that moved differently than the rest, wandering stars. That's where the word planet came from. So, in that sense, even though planets are not stars, it is accurate to call them that due to their history.
telescope
Planets orbit stars. Our planet (earth) orbits a star we call the sun.
This will never happen.
An astronomer
Comparative Planetology
the Greeks called the planets wanderers