Constellations and
Patterns in the Sky

This file is not yet finished

Star Patterns in the Sky

  • What are they? 88 currently recognized patterns [There used to be other ones, no longer officially recognized, like the XIX century Quadrans Muralis, after which the Quadrantid meteor shower is named, or the Pleiades]; Are they real groups of stars?
  • Examples: Ursa major (with the Big Dipper and Mizar); Cygnus; Lyra; Orion; Taurus; the Zodiac, 12 constellations (plus Ophiuchus!) along the Sun's path, the ecliptic (2000 years ago).

The Significance of Constellations

  • General idea: Humans observed and named constellations because of their evocative shapes, to keep track of the time of the year, as locations in the sky where things happened, like planet-related events.
  • Names of constellations: Chinese constellations have names that represent palaces and gardens, generals and ministers; In western culture the northern ones are usually animals or mythical figures (southern ones can be "technological").
  • Example: Aries and the "Star of Bethlehem".

  Seasonal Changes

  • Why do constellations change? At diferent times of the year, the Earth is at different points along its orbit, and at night we face different directions.
  • Examples: Scorpius in summer, Leo in spring, Orion in winter.

  Other Patterns in the Sky

  • Planetary alignments: The ancient Chinese believed that a planet conjunction was an omen of change, based on the fact that astronomers saw a five-planet conjunction, in the constellation Dongjing (Gemini), one year after the Han Dynasty came to power in 605 BC; but alignments really have no effect on Earth or Earthlings.

  Examples of Constellations

  • The Zodiac: From "zodiakos kyklos", the circle of animals along the ecliptic [12, Ophiuchus having been discarded]; To understand the origin of names, must realize that the Earth's axis has precessed over 2000 years.
  • Lyra: Apollo's harp.
  • Orion: The hunter.

page by luca bombelli <bombelli at>, modified 29 sep 2012