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Bone carvings that show the phases of the Moon.
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Babylonians record and predict lunar eclipses.
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Aristarchus invents the first heliocentric, or Sun-centered, model of the solar system as an alternative to the Earth-centered model.
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Eratosthenes measures the circumference of the earth with surprising accuracy!
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Earliest record of Halley's Comet.
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Hipparchus develops the first acccurate star map and star catalogue with over 850 of the brightest stars.
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Ptolemy models an Earth-centric solar system with circular orbits. This model accurately predicts the positions of the planets, but as we know, Earth isn't truly the center of the solar system!
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Construction of an observatory in Cairo was begun in 1120 A.D. This is possibly the first observatory built in Medieval Islam. Unfortunately, the patron of the observatory was found guilty of several crimes including communication with Saturn, and was sentenced to death. The observatory was then destroyed in 1125 A.D. and the personnel were forced to flee for their lives.
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An observatory was built for the famous Persian astronomer, Nasir al-Din al-Tusi. The patron of the observatory was Mongol ruler, Hulagu, who was addicted to astrology. The observatory, built upon a flattened hill, was named Maragha observatory. The observatory included an extensive library and many instruments set up in the open air.
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Copernicus publishes his heliocentric theory of the Universe.
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Hans Lippershey, a Dutch spectacles maker invents the telescope.
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Galileo uses telescope for astronomical purposes. He discovers 4 Jovian moons, the Moon's craters and the Milky Way galaxy.
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Kepler's First and Second Laws of Planetary Motions are announced.
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Asaph Hall discovers Phobos and Deimos, the moons of Mars.
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New evidence found for water on Mars.
