ANCIENT ASTRONOMY

• Astronomy


  The science of the universe outside of our planet. This is the branch of physical science dealing with heavenly bodies.
• Eudoxus


  • Proposed a system of fixed spheres. He believed that the Sun, the moon, the five known planets and the stars were attached to these spheres which carried the heavenly bodies while they revolved around the stationary Earth.
• Claudius Ptolemy


  • Believed that the earth was the center of the universe. His Ptolemic Model claimed that the planets moved in a complicated system of circles. This geocentric model also became known as the Ptolemic System.
• Aristarchus


  • The very first Greek to profess the heliocentric view. The word helios means sun; centric means centered. This heliocentric view considered the sun as the center of the universe. He learned that the sun was many time farther than the moon and that it was much larger than the earth.
• Heliocentric model


  Considered the sun as the center of the universe
• Tycho Brahe


  • A Danish astronomer and nobleman who made accurate observations of the movement of celestial bodies in an observatory built for him by King Frederick II of Denmark in 1576. He was able to invent different astronomical instruments, with the help of his assistants, and made an extensive study of the solar system. He was able to determine the position of 777 fixed stars accurately.
• Aristotle


  • Believed that the Earth is spherical in shape since it always casts a curved shadow when it eclipses the moon. He also believed that the Earth was the center of the universe. The planets and stars were concentric, crystalline spheres centered on the Earth.
• Eclipse


  An obscuring of the light from one celestial body by the passage of another between it and the observer or between it and its source of illumination. When one celestial body such as a moon or planet moves into the shadow of another celestial body.
• Phases of the Moon


  As the moon orbits the Earth, we see a different phase of the moon. It takes 27 days, 7 hours, and 43 minutes for our Moon to complete one full orbit around Earth. This is called the sidereal month, and is measured by our Moon's position relative to distant "fixed" stars. However, it takes our Moon about 29.5 days to complete one cycle of phases (from full Moon to full Moon).
• Phases of the Moon

  • Waxing
  • Gibbous
  • New Moon
• Moon


  Earth's natural satellite which is a relatively small object that is orbiting around a planet.
• Annual motion


  The apparent yearly movement of the stars as observed from Earth as a direct effect of the Earth's revolution around the sun.
• Rising and Setting of the Sun

  Babylonian and Egyptian civilizations used a primitive version of a sundial, called gnomon, in systematically observing the motion of the sun. By looking at the shadows that the gnomon casts, they were able to observe that the sun rises in the eastern part of the sky, reaches its highest point in midday, and sets in the western part of the sky.