A clock
I'm studying to become an astronomer.
Astronomer's are people (scientists) who study celestial bodies. So by profession an astronomer uses a telescope and not a microscope.
Sosigenes created the calendar to follow the equinoxes. He used the Julian Calendar that was created by Julius Caesar in 46 B.C. To do this he calculated that 23 days be added after February 23rd, two months be added between the end of November and the beginning of December. Thus, adding 67 days to the "then" calendar.
A telescope is the instrument an astronomer uses to study matter in space.
Use a Caterpillar!
For shorter distances astronomer often use the AU. One AU is the distance from the Earth to the sun. For longer distances they will use the light year. One light year is the distance that a beam of light in a vacuum will travel in one year.
Galileo.
telescope
a lot
He was not the first astronomer; there were plenty before him going back to the Babylonians at least. Galileo, however, was the first to use a telescope.
You can calculate the aggregate percentage of marks obtained in class twelfth in CBSE for the year 2004 by calculating it using a calculator. You use the formula to calculate it.
Astronomers use a camera. It begins with the letter c.