He discovered the four moons of Jupiter.
Modern astronomy.
From 1609 till his death.
Some of Galileo's most significant work was in the field of kinematics, identifying that the total ...by him (or to be written by him) were forbidden, though this latter part was not enforced. ... Galileo Galilei - major areas of study ...
Galileo !
Galileo Galilei is most famous for his development and improvement of the telescope, his support of the heliocentric theory proposed by Copernicus, his discoveries in astronomy (such as the moons of Jupiter and sunspots), and his struggle with the Catholic Church over his beliefs.
Galileo Galilei [-:
I believe that at the time of Galileo and other pioneers in astronomy there was no formal astronomy study; he (and others) must have learned most of what they knew by themselves.
Galileo Galilei
Modern astronomy.
Astronomy
In astronomy, he used a telescope.
Yes
astronomy and philosophy.
From 1609 till his death.
yes.
Astronomy/physics
Galileo !