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The Autumn Sky

The autumn equinox arrived at 6:54 PM PDT on September 22, 2017. While the summer constellations sink into the western horizon, the autumn constellations start to rise. By midnight, they are overhead. The autumn sky lacks the bright stars of the summer and winter skies which can make identifying individual constellation a challenge. At the heart of the autumn sky is six constellations telling the ancient Greek story of Perseus and Andromeda. The players depicted in their celestial spheres are: Andromeda, fair maiden chained to the rocks. Cetus - the terrible sea monster for whom Andromeda is a snack. King Cepheus and Queen Cassiopeia watch on as their daughter is sacrificed. The winged horse Pegasus brings our hero Perseus, holding the Medusa head and brandishing his sword, to the rescue.

Moon Phases

  • Sep. 24 - Full Moon
  • Oct. 2 - Last Quarter
  • Oct. 8 - New Moon
  • Oct. 16 - First Quarter
  • Oct. 24 - Full Moon
  • Oct. 31 - Last Quarter
  • Nov. 7 - New Moon
  • Nov. 15 - First Quarter
  • Nov. 22 - Full Moon
  • Nov. 29 - Last Quarter
  • Dec. 6 - New Moon
  • Dec. 15 - First Quarter
  • Griffith Observatory

Astronomically speaking, one of the most identifiable feature of the Autumn sky is the Square of Pegasus asterism. Using the Square as a starting point, a long "V" pattern starts at the north-eastern corner of the Square and marks the constellation of Andromeda. In Andromeda is one of the most recognizable galaxies and a true treasure of the fall sky, M31 - The Andromeda Galaxy. Once called the Andromeda Nebula, astronomy great Edwin Hubble used Cepheid variables in the Andromeda nebula to determine that the nebula was too distant, nearly 250,000,000 light-years, to be part of our Milky Way and thus was a galaxy onto itself. Opposite M31 and its guide stars is M33 in Triangulum. M33 is a large pin-wheel spiral galaxy. The large "W", north of Andromeda, makes up the constellation of Cassiopeia. Between Cassiopeia and Perseus is a favorite of binocular and wide field scopes, the Double Cluster, NGC 869 and NGC 884. Also in Perseus is the Demon Star, Algor, who's regular eclipses in its multistar system cause Algol to change in brightness giving to the notion that it was demonic.  Cepheus is a rather non-descript constellation is near the north pole. Finally, the water constellations: Aquarius, Pieces, Cetus and Eridanus  make up the rest of the autumn sky though they are not very bright.

Planets: The summer planets are sinking into the west as fall proceeds.  Mercury will be visible in the evening between Oct. 23 - Nov. 13. Venus returns as the morning star beginning Nov. 5.  Mars continues to be visible in the evening as it slowly dims from its brightest in July.  Jupiter sinks in the west will be out of view by Nov. 7 but will reappear in the morning sky beginning Dec. 15. Saturn will also be edging towards the west and will disappear from view by Dec. 16.  Uranus is an evening planet moving from Aries to Pisces by Dec. 4.  Neptune is visible in the evenings in Aquarius.  On Dec. 7, it will be a quarter of a degree west of Mars.