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30,000 BCE
The first records of early astronomical observers.
Bone carvings that show the phases of the Moon. -
700 BCE
Babylonian's recordings and predictions
Babylonians record and predict lunar eclipses. -
280 BCE
Heliocentric model of the solar system
Aristarchus invents the first heliocentric, or Sun-centered, model of the solar system as an alternative to the Earth-centered model. -
240 BCE
Eratosthenes measurings
Eratosthenes measures the circumference of the earth with surprising accuracy! -
164 BCE
Halley's Comet
Earliest record of Halley's Comet. -
130 BCE
Star Map
Hipparchus develops the first acccurate star map and star catalogue with over 850 of the brightest stars. -
140
Ptolemy models
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! -
Sep 13, 1120
Cairo Observatory
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. -
Sep 13, 1259
Observatoty in Iran
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. -
Sep 13, 1543
Heliocentric Theory of the Universe
Copernicus publishes his heliocentric theory of the Universe. -
Telescope
Hans Lippershey, a Dutch spectacles maker invents the telescope. -
Galileo's telescope
Galileo uses telescope for astronomical purposes. He discovers 4 Jovian moons, the Moon's craters and the Milky Way galaxy. -
Kepler
Kepler's First and Second Laws of Planetary Motions are announced. -
Phobos and Deimos
Asaph Hall discovers Phobos and Deimos, the moons of Mars. -
Water on Mars
New evidence found for water on Mars.
