History of Astronomy

Aristarchus of Samos was an ancient Greek astronomer and mathematician. Within his life time, Aristarchus measured or estimated the size of the Moon, the Sun, and the Earth.
https://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Aristarchos_von_Samos_%28Denkmal%29.jpeg/220px-Aristarchos_von_Samos_%28Denkmal%29.jpeg
https://en.wikipedia.org/wiki/Aristarchus_of_Samos

Hipparchus was a greek Anatolian astronomer, geographer, and mathematician. He is best known for his incidental discovery of equinoxes.
https://upload.wikimedia.org/wikipedia/commons/thumb/5/50/Hipparchos_1.jpeg/220px-Hipparchos_1.jpeg
https://en.wikipedia.org/wiki/Hipparchus

Aryabhata I was the first of the major mathematician-astronomers from the classical age of Indian mathematics and Indian astronomy. He was the first ever astronomer to believe that planets revolve around the sun, made an accurate approximation of the Earth's circumference and diameter, and also discovered how the lunar eclipse and solar eclipse happen for the first time.
https://upload.wikimedia.org/wikipedia/commons/thumb/a/af/2064_aryabhata-crp.jpg/220px-2064_aryabhata-crp.jpg
https://en.wikipedia.org/wiki/Aryabhata

Nicholas Copernicus was a renaissance man, which means he worked in may fields such as, astronomy, biology, mathematics, etc. He did not believe or agree with the Ptolemaic system. He came up with the Heliocentric theory which said the Earth revolved around the sun; however, there was no proof or evidence.
https://upload.wikimedia.org/wikipedia/commons/f/f2/Nikolaus_Kopernikus.jpg
https://en.wikipedia.org/wiki/Nicolaus_Copernicus

Galileo Galilei was an Italian polymath, which means he had a wide range of learning. He studied astronomy, physics, engineering, philosophy, and mathematics. He used the recently invented telescope to find out Jupiter has 4 moons and Saturn has rings.
https://www.universetoday.com/wp-content/uploads/2009/12/galileo-e1435358932718.jpg
https://en.wikipedia.org/wiki/Galileo_Galilei

Johannes Kepler was a German mathematician, astronomer, and astrologer. created the three laws of planetary motion that we still use to this day. The first two laws were created in 1609, and the third law was created in 1619.
Law 1: All orbits are ellipses
Law 2: The closer to perihelion, the faster you will spin, and the closer to the aphelion, the slower you would spin.
Law 3: The ratio of the squares of the time it takes to orbit once is equal to the ration of the cubes to the semi major axis.
https://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Johannes_Kepler_1610.jpg/220px-Johannes_Kepler_1610.jpg
https://en.wikipedia.org/wiki/Johannes_Kepler

Issac Newton was an English mathematician, astronomer, and physicist. Newton discovered the force of gravity in 1687 and created an equation that would count for all matter, explain all gravitational pull, and accurately measure the force of gravity with two objects.
https://upload.wikimedia.org/wikipedia/commons/3/39/GodfreyKneller-IsaacNewton-1689.jpg
https://en.wikipedia.org/wiki/Isaac_Newton

Albert Einstein was a German-born theoretical physicist. Einstein took on Newton's work in the force of gravity and worked after he died. In 1905, he came up with a theory where gravity warps space-time. This later became known as the Theory of Relativity.
https://upload.wikimedia.org/wikipedia/commons/d/d3/Albert_Einstein_Head.jpg
https://en.wikipedia.org/wiki/Albert_Einstein

Gerard Kuiper was a Dutch–American astronomer, planetary scientist, selenographer, author and professor. He proposed an influential theory that there was a disk shaped belt orbiting the sun farther then Neptune. It was later confirmed in the 1990s and named the Kuiper Belt.
https://www.windows2universe.org/people/images/kuiper.gif
https://en.wikipedia.org/wiki/Gerard_Kuiper

Stephen Hawking is an English theoretical physicist, cosmologist, author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge. Stephen Hawking is an amazing scientist and he is known for his contributions in the field of cosmology, general relativity and quantum gravity, especially in the context of black holes.
http://i0.kym-cdn.com/entries/icons/original/000/020/303/Stephen-Hawking-387288.jpg