Content for Hipparchus (190 BC – 120 BC)
Hipparchus, a Greek astrologer, astronomer and geographer is known as the founder of trigonometry and considered one of the greatest of the ancient astronomers.
Hipparchus observed star positions and luminosity and produced the first known catalogue of stars – of which he counted over 850. He was one of the first to examine orbits and the length of the seasons and fter measuring the equinox, noticed a shift in the position of stars. Using geometrical models he explained the motion of the sun and the moon and believed everything moved in perfect circular cycles. As a major contribution to mathematics, he divided a circle into 360 degrees – and created the first trigonometry table. The length of year was calculated to within 6.5 minutes!