Stars over Sisters

It's now the month of October, and the night sky is changing. There are new things to see and discover.

The five constellations of Andromeda, Cassiopeia, Cepheus, Pegasus and Perseus are currently found in the eastern sky at nightfall. These star groupings are not only neighbors to each other in the sky, but they also are linked in one of the most interesting stories in all of Greek mythology.

King Cepheus and his wife, Queen Cassiopeia, ruled ancient Ethiopia. Cassiopeia once boasted that their daughter, Princess Andromeda, was more beautiful than any of the sea nymphs. The queen's vanity offended the sea nymphs, so they complained to Poseidon, the sea god. As punishment, Poseidon sent a sea monster to ravage the kingdom of Ethiopia.

The only way for the curse to be lifted was for the king and queen to sacrifice their daughter to the monster. So Andromeda was chained to rocks along the seashore to await her fate.

Meanwhile, the hero Perseus was on a mission to slay the Gorgan Medusa, ordered by the goddess Athena. After Perseus beheaded Medusa, Pegasus, the winged horse, was born from her blood. Some accounts say that Perseus rode Pegasus to Ethiopia to save Andromeda from the sea monster. He got there in the nick of time and turned the monster to stone by showing it the ugly stare of Medusa's head. Perseus and Andromeda were eventually married, and Pegasus carried Zeus's lightning bolts, earning him a constellation among the stars.

There are a couple of very nice deep-sky objects in this part of the sky. The most prominent is the great galaxy in the constellation of Andromeda. It can be found between the square-shaped constellation of Pegasus and the "W" shape of Cassiopeia, and at 2.5 million light-years distant, is the farthest object that can be seen from the earth with your bare eyes. When searching for the Andromeda Galaxy, look to the northeast at nightfall and straight overhead at midnight.

Another object well worth observing is the Double Cluster. These are two beautiful open star clusters that lie side by side in space and are named NGC 869 and NGC 884. Both have supergiant suns in them. These clusters are best viewed at very low power in a telescope or through binoculars, and are found between Cassiopeia and the northern portion of Perseus.

The Orionid meteor shower peaks on the night of October 20 and morning of October 21. The timing couldn't be better since new moon occurs on October 19. Up to 20 shooting stars an hour may be seen emanating from Orion's club. The best hours for viewing are from midnight to dawn.

Of the five visible planets, only Jupiter and Saturn remain in the evening sky. At the beginning of the month, Jupiter is very low in the western sky-it slips behind the sun on October 26. Saturn, on the other hand, is well up in the southwestern sky. Mercury is a morning planet early in the month, then transitions to an evening object after October 8.

Venus and Mars put on quite a show in the pre-dawn sky this month. On October 5 the two planets are separated by just 0.2 degrees. While both planets begin the month in Leo, Venus moves into Virgo on October 9; the slower-moving Mars does the same on October 12.

October's lunar cycle features the Full Harvest Moon on the fifth, third quarter on the 12th, new moon on the 19th and first quarter the 27th.

To learn more about the night sky, all are invited to attend the Stars over Sisters starwatch on Saturday, October 21 at the Sisters Park & Recreation District building, beginning at 7 p.m. Following a brief presentation, visitors will have an opportunity to view celestial objects through telescopes provided by members of the Sisters Astronomy Club. The event is free.