Eratosthenes of Cyrene (276-196 BCE)

Greek mathematician, astronomer, and geographer that theorized the Earth was round in a time period where almost everyone believed it was flat. He used the sun to measure the size of the Earth and was only 211 miles off of the correct measurement.

Claudius Ptolemy (90-168 CE)

Greek mathematician and astronomer that set up the Ptolemaic system where every celestial object revolved around the earth. Present-day, this is obviously incorrect, but he started generating ideas of planetary locations and also catalouged and named 48 constellations that we still know and use today.

Abd al-Rahman al-Sufi (903-986 CE)

Persian astronomer that made the first observation of the Andromeda Galaxy.

Nicolaus Copernicus (1473-1543)

Polish astronomer that proposed the heliocentric solar system.

Johannes Kepler (1571-1630)

Danish astronomer that determined that planets travel around the sun in ellipses, not circles, which led him to calculate three laws of planetary motion.

Galileo Galilei (1564-1642)

Italian mathematician, astronomer, physicist, and philosopher that immensely improved the optical telescope and discovered Jupiter’s main moons and the rings of Saturn.

Giovanni Cassini (1625-1712)

Italian astronomer that measured how long it took Jupiter and Mars to rotate as well as discovered 4 moons of Saturn and the gaps in Saturn’s rings.

Christiaan Huygens (1629-1695)

Dutch scientist that proposed the earliest theory of light as well as improved the telescope and discovered Saturn’s largest moon, Titan. He also made the first drawing of the Orion Nebula.

Isaac Newton (1643-1727)

English astronomer known for his theories of gravity, three laws of motion, and many other contributions to math and science. He theorized that Earth’s gravitational pull could extend as far as the moon or even further.

Charles Messier (1730-1817)

French astronomer that created a database of 103 known celestial objects at that time. He also discovered 13 comets.

William Herschel (1738-1822) & Caroline Herschel (1750-1848)

The Herschel siblings were British astronomers. William cataloged over 2,500 deep sky objects, as well as discovered Uranus and its 2 brightest moons, 2 of Saturn’s moons, and the Martian ice caps on Mars. His sister, Caroline, was the first woman to discover a comet.

Annie Jump Cannon (1863-1941)

American astronomer known as the “census taker of the sky” due to her development of the Harvard Spectral System, still used today, that allowed her to classify around 350,000 stars manually. It was based on her discovery that stars’ color emission could identify its composing elements.

Albert Einstein (1879-1955)

German physicist that suggested that Newton’s Laws of Motion were the same throughout the entire universe, the speed of light in a vacuum is constant, and that space and time are linked and distorted by gravity.

Edwin Hubble (1899-1953)

American astronomer that determined that the universe was continually expanding

Harlow Shapley (1885-1972)

American astronomer that calculated the size of the Milky Way Galaxy and the general location of its center.

Stephen Hawking (1942-2018)

British astronomer that theorized that, just as the universe began with the Big Bang, it would have to come to an end. He hypothesized that it would all end within black holes.

Sources:

• https://www.space.com/16095-famous-astronomers.html
• http://cnr2.kent.edu/~manley/astronomers.html