News and Opinion from Sisters, Oregon

Stars over Sisters 11/02/2021

One well-known, easy- to-find stellar grouping of the autumn season is Andromeda, the Chained Maiden. It is visible to all who live in the Northern Hemisphere and is bordered by the constellations of Cassiopeia, Lacerta, Pegasus, Perseus, Pisces, and Triangulum. Andromeda is well up in the northeast sky by nightfall.

The brightest star in Andromeda is Alpheratz, also known as Sirrah. It is a spectroscopic binary star, meaning the two stars are orbiting each other very close together. Alpheratz A, the brighter component, is particularly interesting because it contains a remarkably high amount of mercury and other elements. It is about 240 times more luminous and 2.3 times bigger than our sun, while Alpheratz B is only some 13 times brighter.

Both stars are approximately 4.5 billion years younger than the sun. The system lies at a distance of about 97 light-years.

Almach, the constellation’s third-brightest luminary, is a favorite target of amateur astronomers because it is a strikingly beautiful double star that’s easy to split. According to “Burnham’s Celestial Handbook,” “the brighter star is golden yellow or slightly orange, and the companion…appears a definite greenish-blue.”

There are several deep- sky objects scattered throughout Andromeda, but only one of them is so magnificent that it has no rival anywhere else in the sky. The famous Andromeda Galaxy is the nearest spiral galaxy to our own Milky Way (approximately 2.5 million light-years away) and about twice the size. The two galaxies are on a collision course and in about four billion years are expected to merge. Glowing at a magnitude of 3.4, the Andromeda Galaxy is the most distant object visible to the unaided eye.

Andromeda, as well as other constellations in the same part of the sky, is prominently featured in one of the most legendary mythological yarns in all of sky lore.

The tale begins with Cepheus and Cassiopeia, king and queen of the fabled land of Ethiopia, and their daughter Andromeda.

Cassiopeia was a vain woman and gloated about her and her daughter’s beauty to the Nereids (sea nymphs).

The queen’s bragging didn’t sit well with the Nereids, so they complained to Poseidon, god of the sea.

As punishment, Poseidon sent the sea monster Cetus to destroy Cepheus’ kingdom.

The only way to avoid this was to sacrifice Andromeda to Cetus.

So she was chained to a rock and left to be slain.

Fortunately, the Greek hero Perseus was in the area and flew down on his winged horse Pegasus to rescue her.

He took her hand in marriage and together they had seven sons and two daughters.

A partial lunar eclipse will take place on the evening of November 18, extending into the early morning of November 19. Although officially listed as a partial eclipse, the earth’s shadow will cover about 97 percent of the moon’s disk. At 10:02 p.m. PST on November 18, the penumbral shadow contacts the moon, followed by the umbral shadow at 11:18 p.m. The eclipse maximum occurs at 1:03 a.m. on November 19.

With a little effort, you will be able to see all five of the visible planets in November. Venus in Sagittarius, and Jupiter and Saturn in Capricornus, will be easy to spot in the evening sky. While Mercury can be seen low in the southeast at dawn, Mars is still too close to the sun to observe until the end of the month.

November’s dark-sky preservation tip: Shield your outdoor lights. Ideally, lamps should only illuminate the area you are intending to light. They should be fully surrounded with shields made of opaque material that directs light downward toward the ground and blocks it from shining into the sky. Some roof overhangs can serve this purpose. A good test for light shields is to stand several yards away from your lights when it is dark to ensure that you can’t see the bulbs.

 

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