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Dec 14, 1546
Tycho Brache
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 Galilei
After the learning of the invention of the spyglass in Holland, he built a telescope of his own, which had a magnification factor of 20. With this new tool, he found mountains and craters on the moon, discovered that the Milky Way was composed of stars, and discovered the four largest moons of Jupiter. -
Dec 27, 1571
Johannes Kepler
Kepler was assigned the task by Tycho Brahe to analyze the observations that Tycho had made of Mars. Of all the planets, the predicted position of Mars had the largest errors and therefore posed the greatest problem. Tycho's data were the best available before the invention of the telescope and the accuracy was good enough for Kepler to show that Mars' orbit would precisely fit an ellipse. -
John Baptist Riccoli
His greatest achievement in astronomy is being known as the first person to study the acceleration rate of a free falling object. -
Giovanni Cassini
Cassini is best know for his discovery of four of Saturn's moons: Iapetus, Rhea, Tethys, and Dione. He is also credited with discovering the Great Red Spot on Jupiter. -
Christoph Arnold
He spotted the great comet of 1683, eight days before Hevelius did. He also observed the great comet of 1686. In 1686, Kirch went to Leipzig. There, he observed the great comet of 1686, together with Gottfried Kirch. -
Edmond Halley
Halley had observed a number of comets and, following 1695, undertook deep studies to calculate their orbits. In 1705, he published his "Astronomiae Cometiae Synopsis", including his observation that the comet he had observed in 1682 had an orbit almost identical to those of the comets of 1531 and 1607, and concluded these were apparitions of one and the same comet, the return of which he predicted for 1758. -
Charles Messier
With the discovery of a further "nebula", his third object and his first original discovery, it seems that he undertook a serious scan of the skies for these objects, as they could frequently fool comet discoverers. -
Joseph-Louis Lagrange
Also contained are methods to solve systems of linear differential equations which used the characteristic value of a linear substitution for the first time. Another problem to which he applied his methods was the study the orbits of Jupiter and Saturn. -
William Herschel
In a long series of remarkable papers, addressed as usual to the Royal Society, and extending from the year 1784 to 1818, when he was eighty years of age, he demonstrated the fact that our sun is a star situated not far from the bifurcation of the Milky Way, and that all the stars visible to us lie more or less in clusters scattered throughout a comparatively thin, but immensely extended stratum.
