StarWatch for the greater Lehigh Valley



214   OCTOBER 1, 2000:     Fall: Looking North
During July we did a round-robin of the 10 p.m. sky starting in the north and moving in an easterly direction. Since then, the sky has spun counterclockwise a quarter turn due to Earth’s orbiting motion. See the map associated with this StarWatch at the web site below. The Big Dipper or Ursa Major, has moved from a position of bowl down, handle up to being nearly horizontal on the horizon. It will be basically invisible for the next several months because of its closeness to buildings, trees, and the lights of the city. High in the north, above and to the right of the North Star, can be found the famed Lady in a Chair, or Queen Cassiopeia. There is no Queen, only a sideways "W" or "M" depending upon your mental persuasion. From rural locales the "W" or "M" may include several additional stars (see web map) which allow the shape to be expanded into the chair upon which she is sitting. Her two eyes can be faintly seen from the country only on the clearest of evenings. To the right and below Cassiopeia in the NE will be found a triangular grouping of stars which will appear to expand outward. That’s Perseus, the Hero, who rescued Cassiopeia’s daughter, Andromeda, from being devoured by Cetus, the Whale or Sea Monster. Cassiopeia had challenged the Sea Nymphs to their rite as "most beautiful." In revenge, Cassiopeia’s lands had been ravaged by a tidal wave and then the monster. To rid her land of Cetus, she sacrificed her daughter. The ploy failed because Andromeda was rescued by Perseus. Cassiopeia’s angered subjects threw her into the sky where she landed on a chair with a crocked back. She spends half of the year upside-down, tied to the chair, her punishment for this evil deed.

Looking North

215   OCTOBER 8, 2000:     Fall: Looking East
This week we continue our tour of the 10:00 p.m. October sky by turning east. Follow the links on the ASD Planetarium’s web site to print out a map. If a good horizon is at hand, you’ll notice three bright stars due east. Two of them are planets. Highest of the three is Saturn. Bright Jupiter is to the left. Below and right of Jupiter is the star Aldebaran, of Taurus. Above this triad is the Seven Sisters or Pleiades visible as a fuzzy patch of light. It is best seen with averted vision. Focusing binoculars on them will reveal a beautiful open cluster of blue-white stars. The Pleiades are between 50-100 million years old, infants by stellar standards. To the right of the Pleiades, but much higher in the sky is the Double Cluster of Perseus. To see them, you’ll definitely need binoculars because the Moon is becoming brighter this week. Last week’s StarWatch detailed Cassiopeia and Perseus. The Double Cluster of Perseus is positioned between the bottom of the "W" of Cassiopeia and the triangular tip of Perseus. Still higher is the Great Square of Pegasus with Andromeda trailing off to the lower left of the square. One of the true gems of the fall and winter sky, the Great Galaxy in Andromeda, is found above the middle star in a grouping of three stars, similar to the handle of the Big Dipper. These stars mark the lower boundary of the maiden who was rescued by Perseus. About one binocular field above the middle star will be a fainter star. An even fainter star will be above it. Now move your binoculars slightly to the right. The fuzzy oval-shape of the second largest galaxy in our local group will come into view. Because of its large size, binoculars often give some of the best views of the Andromeda Galaxy.

Looking East

216   OCTOBER 16, 2000:     Fall: Looking South
We have been circling the October sky and we’re now looking south at about 10 p.m. The nearly full moon will be a nuisance during the first few days of this week. By following the StarWatch links at the web site below, you can print a map that details the sky for this week. The southern sky is currently full of water creatures like Capricornus, the Sea Goat; Aquarius, the Water Bearer; Cetus, the Whale or Sea Monster; Pisces, the Fish; Delphinus, the Dolphin; and Pegasus, the Flying Horse. Pegasus’ four brightest stars, now nearly overhead in the south, are called the Great Square and represent its body. Actually, the star on the square’s upper left, called Alpheratz, is part of the constellation of Andromeda, but it really seems to belong to the horse. What does Pegasus have to do with water? In one story, Pegasus transported the hero Perseus home after he slew the Medusa. The Medusa was best known for her bad hair days. She had slithering snakes coming from her head, a real trick to brush out, and she was so ugly that looking into her eyes changed the surprised beholder into stone. Hence we have a reason for all of those Grecian statues that graced the ancient world. Neptune, who had loved the Medusa when she was young and beautiful, created Pegasus from white beach sand, glistening sea foam, and the Medusa’s blood. Remember that Pegasus is only half a horse because the back legs are really Andromeda. According to the myth, the horse’s body is suppose to be rising from the foam of the ocean. Taking the two right hand stars of the Great Square, Scheat and Markab, follow them south to near the horizon where you will notice one solitary star gleaming. That’s Fomalhaut of Pisces Austrinus, the Southern Fish.

Looking South

217   OCTOBER 22, 2000:     Fall: Looking West
This week’s sky tour looks west at 10:00 p.m. Print a map of these stars at the Planetarium’s web site given below. The Great Summer Triangle consisting of Vega, Deneb, and Altair is now in the west. The highest of the three, Deneb, the tail of Cygnus, the Swan, is still only 20 degrees off the zenith. The zenith is the point directly overhead. From the Lehigh Valley, Cygnus looks more like a cross. By Christmas it will stand on the western horizon just after dark. The lowest luminary in the Cross, Alberio, is a beautiful double star which can be easily resolved through small telescopes. The components are separated by one-half minute of arc. The fainter star will look bluish white while the brighter member will have a much warmer yellowish hue. Larger aperture telescopes will accentuate this color difference since they gather more light. Above Alberio, along the staff of the Cross and just above Eta Cygni lies one of the most interesting objects in the heavens, Cygnus X-1, the first black hole to be discovered (see map). You can’t see it directly since black holes are black, but you’ll be looking in the correct direction by viewing Eta. Discovered as an X-ray source in 1965, it was pinpointed as a radio source in 1971. Located in the same position was a very massive star, HDE 226868. Spectroscopic analysis of the star revealed that it was orbiting something unseen. Determining the orbital period allowed astronomers to calculate easily the mass of the system at nearly 40 times that of the sun. The mass of the visible star was determined to be 30 solar masses leaving the unseen companion weighing in at 5-8 solar masses. The only plausible explanation was that the unseen companion was a black hole.

Looking West

218   OCTOBER 29, 2000:     Fall: Looking Overhead
The concluding episode of our tour of the 10:00 p.m. October sky is the zenith. You can download a map by following the StarWatch links at the ASD Planetarium’s web address given below. When Americans think about constellations, most often they visualize the Big Dipper or Drinking Gourd. If you were English, it would be the Plough (Plow); and if German, the Wagon. They are all composed of the same seven stars, but seen differently by different nationalities. Worldwide they are officially recognized as part of Ursa Major, the Great Bear, by the International Astronomical Union which formalized the heavens in 1928. The Dipper, Drinking Gourd, Plough, and Wagon are called asterisms, famous groupings of stars, but not officially recognized as constellations. The October sky overhead is filled with these objects. Presently, the most famous is the Great Square, composed of the body of the Pegasus, the Flying Horse. Look a little south of the zenith to see it. Below the Great Square will be a circle of faint stars, the Western Fish of Pisces, also known as the Circlet. Binoculars will clarify the grouping, as well as a more widely-spaced arrangement to the Great Square’s left, called the Northern Fish. To the right of the Square, you’ll see the three bright stars of Great Summer Triangle settling into the western sky. Deneb, the faintest and closest to the Great Square, is itself part of the asterism called the Northern Cross. It is really composed of the brightest stars of Cygnus, the Swan, but like the Dipper, it represents what you’ll see from our light-drenched Lehigh Valley skies. Looking east, don’t miss the famous "W" of Cassiopeia’s chair or her eyes. Binoculars are a must for the eyes. Good Viewing!

Looking Overhead

October Star Map

October Moon Phase Calendar