500 years ago, no one really knew anything about space. Anything and everything that we know today about outer space are because someone out there gazed at the stars and wondered about its home. Astronomers are scientists that love the cosmos and have dedicated their lives for eons to understand it better. Today, we have countries all over the world pooling resources to uncover even more truths about the billions of astronomical bodies beyond the observable universe. However, this knowledge would not have been ours if the ten great astronomers mentioned below did not exist. While the discovery of space cannot be credited to a single individual, these ten played a huge part in discerning the space. 

Tycho Brahe (1546-1601)

Tycho Brahe, a Danish nobleman was a writer, astrologer, alchemist, and astronomer born on December 14, 1546, in Knutstorp Manor, Sweden. He was famous for his comprehensive and accurate astronomical observations. In the pre-telescopic era, he was known as “the first competent mind in modern astronomy to feel ardently the passion for exact empirical facts”. His observations were far more accurate than anyone else’s observations during that time. He cataloged thousands of stars and other celestial objects with an accuracy that was unheard of with the technology available in 1572. Brahe was also the first to scientifically acknowledge a supernova event. 

Claudius Ptolemy (100-170 AD)

A Greek astronomer, mathematician, astrologer, and geographer, Ptolemy was born in 100 AD in Alexandria, Egypt under the Roman Empire’s rule. He was believed to be the last of the great astronomers before the world descended into the dark ages. He preserved Hipparchus’s star catalogue, which was included in Almagest, his astronomical magnum opus. It is because of this astronomy text that Ptolemy received his legendary status as it was one of the most important texts in astronomy for 1500 years after his death. He also created a set of tables, which simplified the task of calculating the position of the stars, the planets, the Sun and the moon, dates of the solar and lunar eclipses among other things.

Gustav Kirchhoff (1824-1887)

On 12 March 1824, German astrophysicist Gustav Robert Kirchhoff was born in present-day Kaliningrad, Russia. He is known for his contribution to the fundamental understanding of spectroscopy, electrical circuits, and black body radiation (he also coined the term in 1862). He was considered a pioneer in astrophysics, just after Newton. Along with his partner, Kirchhoff invented the spectroscope, which he used to identify the elements in the Sun. In 1859, he concluded that the Sun contains sodium and rubidium & caesium in 1861.

William Herschel (1738-1822)

Frederick William Herschel was a German-born British composer and astronomer born on November 15, 1738, in the electorate of Hanover before coming to Great Britain at the age of 19 in 1757. He worked alongside his sister Caroline Herschel who was a fellow astronomer. There is a reason why he is known as ‘the father of modern sidereal astronomy’. His list of scientific discoveries is as long as an arm and here are some of the most important contributions of Herschel to the field of astronomy. He was the one who first discovered the planet Uranus, determined solar apex’s coordinates, perceived the binary character of some double stars, and detected the Sun’s motion in space.

Hipparchus of Nicaea (c. 190-c. 120 BC)

Hipparchus was a Greek geographer, astronomer, and mathematician who is called the founder of trigonometry. However, he is most known for his ‘incidental discovery of the precession of the equinoxes’. He is also considered antiquity’s greatest astronomer as well as the greatest astronomical observer in ancient times. He determined the length of several months and years and catalogued 1100 stars to name a few of his achievements. His work inspired a large part of his successor Ptolemy’s astronomical work ‘Almagest’.

Albert Einstein (1879-1955)

Albert Einstein has been a household name for over a century now. He is one of the most important scientists in the 20th century. While he is a German-born theoretical physicist, his theory of relativity revolutionized modern astrophysics. Born on 14th March 1879 in Ulm, Germany, Einstein’s dream was ‘a grand unification of physical theory’, which astronomers and physicists of today still believe to be their main goal.

Johannes Kepler (1571-1630)

Johannes Kepler was born just after Christmas on 27th December 1571 in Germany. He was an astrologer, astronomer, and mathematician who is known for his books on Harmonices Mundi, Astronomia Nova & Epitome Astronomiae Copernicanae and the laws of planetary motion. Everyone knew that he was Tycho Brahe’s assistant but the fact that their relationship was quite strained is only known by a few. Tycho was always worried about Kepler outshining him. He was the first astronomer to explain the motion of all the planets in our solar system as well as how the moon influences the tides. 

Edwin Hubble (1889-1953)

Edwin P. Hubble, an American astronomer made one of the most historic discoveries in the 20th century as well as among all the scientists in this list. Hubble discovered that Milky Way is not the only galaxy in the universe. There are millions of galaxies outside the Milky Way. While many scientists before him had worked towards finding other galaxies, it was him who made this observation using the Hooker telescope in 1923. He bursted the world’s balloon and introduced us to intergalactic space, which is infinite with billions of stars spread across billions of light-years. 

Nicolaus Copernicus (1473-1543)

Born in 1473, Copernicus was a Renaissance-era astronomer, economist, governor, physician, diplomat, translator, and mathematician that is credited with formulating a model that put the Sun at the centre rather than Earth in the Universe. It was him that proposed that planets are the ones that revolve around the Sun instead of the Earth, which was wildly believed during that period. However, this theory was not received with acceptance. He was sentenced with house arrest for engaging in heresy against the Roman Catholic Church. It took almost a century for the heliocentric model to be taken seriously. 

Galileo Galilei (1564-1642)

The greatest astronomer in the history of mankind is no doubt Galileo Galilei. He was an Italian astronomer who is sometimes described as a lucky astronomer. He was born after the telescope was invested (contrary to popular beliefs, he did not invent the telescope). However, he did make his own lenses, which increased the magnification 8-9 times than the spyglass. He is most known for finding the 4 Jupiter’s moon, which are named after him. He was also the one who observed the craters on the moon for the first time as well as sunspots. He also noticed the rings of Saturn, which none of his contemporaries can be credited for. Just like Copernicus, Galileo was also sentenced to house arrest for the 9 remaining years of his life for going against the Catholic Church and believing that the planets orbited around the Sun instead of the Earth.