Uncle Bob's Astronomy Pages
Autumn Sky Favorites
This is the fourth and final article in a series devoted to the beautiful and thought-provoking features in the night sky. We began with a sweeping look at the winter sky which included some fading fall favorites. At this time of year, if we look late enough and east enough, we can see those winter twinklers returning to prominence. Except for the positions of planets, we get the same show year after year. A sky map is provided below.
Oh yes, there will be gradual changes in the appearance of the sky, and I'll mention two here, but keep in mind that grass grows a lot faster. First, in 10,000 years or so, Polaris will not be the pole star and help us find due north (I say us!). This is caused by a circular wobble in the axis of earth, the big top we spin around on, and it is called precession. Second, some stars move relative to the relatively fixed stars and galaxies. These stars seem to be on a mission, and some of them will cause some constellations to change shape in the next few millennia. The stars at each end of the Big Dipper, for example, will cause the eventual shortening of the handle, and worse, the spillage of contents from the drinking gourd. These stars exhibit what is called proper motion.
I thought this would be a good time to mention a few astronomical resources which I think would benefit the person seeking more information. For a first book I recommend The Stars by H.A.Rey. This is not solely a children's book, but it does employ a visual approach which makes constellations more obvious, and it explains much of the operation of the solar system. I'm happy to note that this book has been in print since 1952, and even though some good books don't hang around very long, this one is still available. For a bit more detail in a highly digestible form, I suggest you look at Chet Raymo's 365 Starry Nights and Fred Schaaf's Seeing the Sky. If you've treated yourself to a good telescope (please, don't treat yourself to a bad one), and you want to look deeper into the gallery, try the Audubon Field Guide to the Night Sky and Schaaf's Seeing the Deep Sky. Finally, for current events and all-around excellent coverage of the hobby and the profession, the magazine Sky & Telescope is a monthly joy. It ranks with the best magazines in any field. Its February 2001 issue also features some of the best websites for astronomy. A well-written chapter or article will have you seeing stars virtually in broad daylight and through cloud cover.
UB proposes a beauty contest for early November. Beg or borrow (but don't steal) a telescope, if possible, to see the two prettiest sights in the northern sky. Our two finalists, having declined the swimsuit competition, are the double stars Alberio and Gamma Andromeda, and we will steer you to them. If you can't cop a scope, binoculars and a dark night should reveal that these two are not ordinary stars. The entrants will be judged on colors, brightness, separation (which allows you to see that they are double stars), contrast, and, sensing a need for an intangible category, dazzle. The two contestants are outlined by triangles on the map.
Alberio, or Beta Cygnus, is the head of the Swan (or the base of the Northern Cross) as described in my summer sky article. The Swan will be found high in the sky and heading west in evening hours. Alberio is at the west end of the swan's long neck. Gamma Andromeda will be found east of the top of the sky, being dragged behind the great wing of Pegasus, called the Great Square. You can't miss the square. Look up and a little east. From the northeast corner of the square, there is a line of stars trailing to the northeast. The star at the corner is Alpha Andromeda (imagine Andromeda's hands clinging to Pegasus' wing for the ride of her life). At about the distances of one side of the square along this line, we next reach Beta, and then Gamma Andromeda, which is the other double star of our desires. Using whatever optics you can muster, take a long time admiring the aesthetics, and then cast your vote. Send your pick, either Alberio or Gamma Andromeda, to Email Uncle Bob. Tell us what factors determined your decision. In the meantime, I'll tell you the story of Andromeda's wild ride. It begins with her parents, Queen Cassiopeia and King Cepheus.
Mama Cass has Poseidon, God of the Sea, beside himself. She has proclaimed herself more beautiful than all of his daughters, the Sea Nymphs. The old trident-wielder lashes out blood being thicker than salt water. He sends Cetus, the Sea Monster, to wreck havoc (and I do mean wreck) on the seacoast of Cepheus' kingdom. In the customary, if peculiar, mythological fashion, Cepheus consults the Oracle, much like the modern day king would consult Madge during a manicure. Madge advises a soak in dishwashing liquid, whereas the Oracle at Ammon said that Cepheus must sacrifice his most beautiful daughter Andromeda. Thinking, 'tis a small price to pay, Cepheus orders Andromeda chained to a rock, there to await the hungry jaws of the whale.
Perseus comes from good hero stock. He is the product of one of the many mixed marriages (god - mortal) found in mythology (in this case, Zeus having had his way with Danais). Perseus establishes a name for himself when he slays the Gorgon Medusa. As the Medusa's blood drips into the sea, a winged horse, Pegasus, springs from the foam. This turns out to be a good thing because Perseus needs transportation. Away they ride to heroic and mythic adventures, Andromeda being the first. Arriving in the nick of time, Perseus falls instantly in love, looses the damsel from her chains, and they depart on Pegasus AirLines. This entire adventure is portrayed every fall in our friendly night skies.
Look high to the north to find the zigzag shape of Cassiopeia. Directly to the west is the King, having a box-shape adjoined to a longish triangle pointing northeast (a clown in a dunce cap is the impression I get). Trailing east of Cassiopeia and northeast beyond the Great Square and Andromeda is Perseus. This constellation's two main features are a long, hobbyhorse-like rocker, and along it, a busy smattering a stars, called a cluster. Cetus the Whale also lurks far to the south. It is a large constellation running east-west.
Finally, you are invited to join thousands of professional and amateur astronomers the nights on or near November 17-18, to watch the Leonid meteor showers. Bundle up big-time and find a high, dry place to recline and take in the whole sky. I suspect the hours after 1 a.m. will be the best because Leo doesn't rise until then, and these meteors tend to be short, bright, and fast. They are called the Leonids because, if traced backwards, they seem to originate near the neck of Leo, the Lion. Every 33 years or so, the Leonids produce a storm of thousands. The last storm was in 1966, but the years 1998-2002 were very active. Are you feeling lucky?
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