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Ptolemy
Born in Egypt. The Almagest is the only surviving comprehensive ancient treatise on astronomy. -
Feb 19, 1493
Copernicus
Born in Torun, Poland. By 1508, Copernicus had begun developing his own celestial model, a heliocentric planetary system. During the second century A.D., Ptolemy had invented a geometric planetary model, which was inconsistent with Aristotle's idea that celestial bodies moved in a circular motion at different speeds around a fixed point, the earth. -
Dec 14, 1546
Brahe
Born in Scania, then part of Denmark, now part of Sweden. As an astronomer, Tycho worked to combine what he saw as the geometrical benefits of the Copernican system with the philosophical benefits of the Ptolemaic system into his own model of the universe, the Tychonic system. Furthermore, he was the last of the major naked eye astronomers, working without telescopes for his observations. -
Feb 15, 1564
Galileo
Born in Pisa, Italy. In 1604, Galileo published The Operations of the Geometrical and Military Compass, revealing his skills with experiments and practical technological applications. He also constructed a hydrostatic balance for measuring small objects. These developments brought him additional income and more recognition. That same year, Galileo refined his theories on motion and falling objects, and developed the universal law of acceleration, which all objects in the universe obeyed. Galileo -
Dec 27, 1571
Kepler
Born in Weil der Stadt. Using the precise data that Tycho had collected, Kepler discovered that the orbit of Mars was an ellipse. In 1609 he published Astronomia Nova, delineating his discoveries, which are now called Kepler's first two laws of planetary motion. -
The spyglass is invented.
Galileo did not invent the telescope. But he did modify a curiosity called the spyglass that in 1609 was beginning to be sold by spectacle makers and peddlers in Europe. -
The first reflecting telescope is built.
Isaac Newton built the new reflecting telescope -
Spiral nebulae are discovered.
In 1845, Lord Rosse used his largest telescope to see the spiral structure of M51. -
Scientists learn how to put silver on glass.
1850’s: German chemists used a chemical reaction to make a silver-on-glass mirror. -
The first permanent solar telescope is built.
By 1904, the Snow Solar Telescope was built and then moved to its permanent home atop Mount Wilson. -
The first radio telescope is built.
An amateur radio operator, Grote Reber, was one of the pioneers of what became known as radio astronomy when he built the first parabolic "dish" radio telescope (9 metres (30 ft) in diameter) in his back yard in Illinois in 1937.