News and Opinion from Sisters, Oregon

Stars over Sisters

If you look into the southeastern sky on a clear November evening, you can see the Greek sea monster Cetus. This is a big constellation, fourth largest, in fact, by area. Its neighboring constellations are Aquarius, Aries, Eridanus, Fornax, Pisces, Sculptor, and Taurus. The creature's head is located about 25 degrees west and 10 degrees south of the bright star Aldebaran in Taurus. During the late fall and winter season, Cetus can be seen by observers from the South Pole to a latitude of approximately 70 degrees north.

The brightest star in Cetus is Beta Ceti (also known as Diphda) that shines with an apparent visual magnitude of 2.02, just a shade dimmer than Alkaid, end star in the handle of the Big Dipper. Diphda is an orange-colored star that is 18 times larger and 2.8 times more massive than our Sun. It lies at a distance of 96 light-years.

There are more than four dozen galaxies in Cetus, but none are bigger or brighter than M77. Discovered by French astronomer Pierre Mechain on October 29, 1780, the size of this galaxy is an estimated 170,000 light-years in diameter, making it twice as big as our Milky Way galaxy. The object is bright too, shining at a magnitude of 9.6 from a distance of 47 million light-years.

Cetus plays a role in one of the best-known myths in all of sky lore. It seems that Cassiopeia, queen of ancient Aethiopia, angered the sea god Poseidon by bragging about her daughter Andromeda's pure beauty. To punish the queen for her boastfulness, the sea god unleashed a giant serpentine-like monster (Cetus) to destroy the kingdom of Aethiopia.

To deal with this terrible situation, King Cepheus consulted the Oracle of Ammon. He was told the only way to save his kingdom was to sacrifice his daughter to Cetus. Reluctantly, Cepheus had his daughter chained to a rock on the seashore to be found by the monster.

But just as Cetus was closing in on Andromeda, Perseus, the hero, arrived on the scene riding upon Pegasus the flying horse. He was returning home from an assignment that required him to slay the Gordon Medusa and bring back her severed head, which he carried in a bag. Medusa's appearance was so horrible that anyone who gazed upon her face would be turned to stone.

Perseus quickly assessed the situation and revealed Medusa's severed head to Cetus, immediately turning the sea creature to stone. Perseus and Andromeda were eventually married. Their union produced seven sons and two daughters.

The peak of the Leonid meteor shower will occur on the evening of November 17 until dawn the next morning. A waxing crescent moon will set before 10 p.m. local time on the 17th, allowing dark skies to prevail throughout the event. Expect to see 10-15 meteors per hour from midnight until dawn. The meteors are caused by Earth moving through the debris field left behind by Comet Tempel-Tuttle.

Because Jupiter reaches opposition on November 3, it is visible all night long. The brilliant planet is currently moving through the constellation of Aries. As dusk deepens, look for Saturn to appear in the southern sky. It is currently in Aquarius.

Mercury becomes an evening planet in November, standing just 3 degrees above the western horizon by mid-month. Presently located in Virgo, Venus is the lone morning planet, rising in the east four hours before the sun. Mars comes into conjunction on November 18, thus is too close to the sun to be observed this month.

Dark sky tip: To help reduce light pollution, make sure your outdoor lights are fully shielded so that light is directed downward.

 

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