NHAS - Today in Astronomy History

	1630	German mathematician and astronomer Johannes Kepler dies. He established the three basic laws of planetary motion (today known simply as "Kepler's Laws"), derived a proof explaining the nature of logarithms, and devised a method of finding the volumes of solids of revolution that predated the development of calculus. His tables of astrometric measurements, at the time the most precise ever created, were instrumental in proving the heliocentric theory of Copernicus, over the Ptolomy's geocentric model, which was favored by Kepler's teacher Tycho Brahe.
	1738	German-British astronomer William Herschel born. He discovered the planet Uranus and its two brightest moons, Titania and Oberon. He also discovered the polar ice caps of Mars, infrared radiation, and Mimas and Enceladus - two of the moons of Saturn. He catalogued nearly a thousand binary stars and 2,514 deep sky objects. His list of deep sky objects, called the "The General Catalogue of Nebulae," was revised and enlarged by L.E. Dreyer in 1888 to became the "New General Catalog." To this day, most nebulae and galaxies are known by their NGC numbers.
	1999	Transit of Mercury across the Sun's disk. Only visible from the southern Pacific ocean.