StarWatch: Moravian College Astronomy

StarWatch for the greater Lehigh Valley

OCTOBER 2008

OCTOBER STAR MAP | STARWATCH INDEX | MOON PHASE CALENDAR

Print Large Sky Charts For 10 p.m. EDT: NORTH | EAST | SOUTH | WEST | ZENITH

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633 OCTOBER 5, 2008: Comfort Food for the Soul: It was party time at Chaco Culture National Historical Park near Nageezi, NM, and I was in charge. When you’re two hours and 70 road miles away from a local store, you can’t afford to make any forgetful mistakes. I was part of the astronomy cadre and because Chaco was located in the backside of beyond, these events attracted nearly all of the 20 permanent residents in the park. I chose to make meatloaf, along with baked potatoes and fresh green beans. My buddy, Brandon Velivis, a former student of mine was in charge of creating a scrumptious 500 layer baklava desert. The dinner went off a little later than planned because of a five hour power outage, but it was a smashing success. We ate until we thought we’d explode; it was so good. Along the way, Tommy Taylor, a retired lawyer from Boston, who had given up the corporate world for skateboarding and astronomy, heaped praises upon my “gutsy” decision to make meatloaf. “It was comfort food,” he declared, “and if it had been just ordinary meatloaf, the meal would have flopped. It had to be at least as good as mom’s meatloaf.” Recently, memories of that story got me thinking about comfort food for the soul. The heavens have 88 official constellations, and one of them is Crux, a small but beautiful cross best viewed from the southern hemisphere. The other is Cygnus the Swan, flying down the backbone of the Milky Way, high in the early evening sky. It too looks like a cross, the Northern Cross, especially from suburbia where many of its fainter stars are obscured by urban lights. If you go outside right after dark, anytime during October, you can easily spot it overhead. A map is included “in this week’s StarWatch” at www.astronomy.org. Oh, and why was my meatloaf so incredibly good? The secret ingredient was beer.

634 OCTOBER 12, 2008: We Aren't in Kansas Anymore: I have always wanted to see a tornado, but living in eastern PA, I never imagined that I would ever be affected by one. On Saturday, Sept. 6 as Tropical Storm Hanna rapidly moved up the eastern seaboard, it spawned one twister which touched down at 2:47 p.m., EDT six blocks east of where I teach at Dieruff HS in Allentown, PA. The tornado moved rapidly, skipping this house and taking the roof off another until it came to Dieruff where it toppled and twisted 50 year-old trees, and peeled the roof off 14 classrooms before passing directly over my planetarium. The whole event took less than two minutes resulting in 1.5 million dollars of damage over 80 percent of that amount to the school. Most tornadoes form from supercells, storms which have their own distinctive counterclockwise rotation. Heavy rainfall takes with it a column of quickly descending and accelerating air, dragging the supercell's rotation towards the ground. This, in turn, creates an area of uplift forming a descending funnel cloud as moist rotating air lifts and condenses. When the funnel cloud reaches the ground, it becomes a tornado. First responders arriving at the school initially thought that the star theater had been heavily damaged. Crews went in and covered the equipment. There was water everywhere. Seventeen classrooms were in shambles, but the extensive damage to the planetarium proved false. Dieruff’s roof had lifted onto the planetarium’s structure making everyone initially believe that the room had been compromised. My closet, however, was a total disaster and that Sunday, I spent salvaging debris hauled outside. We were all so fortunate. Twenty-four hours earlier the school would have been filled with students ready for Friday dismissal. Thank goodness, we were spared that ordeal. Photos are online.

635 OCTOBER 19, 2008: Cygnus: Still Flying High: With cool, crisp Canadian air filtering down from the north, October is one of the finest times of the year to mix it up with the heavens. The moon at is at last quarter on Tuesday which means that it is rising later each night and won’t be any bother for early evening viewing. Although we are well into autumn, the summer constellations are still hanging overhead throughout much of the month as soon as it gets dark. That is because the daylight hours have been rapidly shrinking with earlier sunsets outpacing later sunrises. The seasonal progression of the heavens appears to be slowed because the sky becomes accessible earlier each evening. Right after dark directly overhead, the three bright stars of the Great Summer Triangle will still be there to greet you. The faintest of the triad is Deneb, the alpha star of Cygnus the Swan, which from suburban locales looks more like a cross. Deneb, at its most recently calculated distance of 3200 light years, is the brightest luminary for its distance in the heavens. If you scan the region surrounding Deneb using binoculars, knots and twists of stars and nebulae associated with our home galaxy will be seen. Cygnus’s body, the staff of the Northern Cross, runs along the spine of our galaxy and provides a way, in more light polluted areas, of knowing where the Milky Way could be seen if skies were dark enough. Just below Deneb is a faint but large nebulosity that looks like the continent of North America. Visible with binoculars, but only from truly rural locales, the North American Nebula is so realistic in its shape that even the country of Mexico and the state of Florida are recognizable. Using binoculars, face SE, positioning Deneb at the top of the field. The North American Nebula will be centered. Pictures are online “at this week’s StarWatch.”

636 OCTOBER 26, 2008: Eyes to the Sky for Venus and Antares: Eyes to the sky this week, because during early twilight, you’ll catch Venus shining brightly, low in the SW. The goddess of love has been there for quite sometime, but difficult to detect because autumn apparitions always place it low to the horizon. If you wait a little longer for twilight to deepen, an added surprise awaits. Antares, the brightest star of Scorpius the Scorpion, will become visible below Venus. With binoculars you’ll see a quaking, red giant Antares, nearly exhausted of fuel, made even more ruby-like by its closeness to the horizon. The twinkling effect will not be Antares getting ready to supernova, but the exceptionally long column of moving, turbulent air that the light from Antares must pass through before reaching the eye. The reddening effect will be exaggerated because that same column of air will scatter or filter the shorter blue and green wavelengths of light, preventing them from reaching our eyes. It is the same phenomenon that reddens the sun and the moon when they are low to the horizon. Another noteworthy aspect of viewing Venus and Antares this week will be their comparative brightness. Venus will be beaming at a magnitude of -4.0, while Antares will shine at +1.1. The Greeks invented this backwards system of calculating brightness, and modern astronomers have quantified it. The brighter an object, the more negative the magnitude with each integer equaling a difference in intensity of 2.51. A disparity of five magnitudes is equivalent to an intensity difference of 100. The variation of 5.1 magnitudes that separates Venus from Antares translates to a 109-fold change in brightness. One hundred nine Antares stars would equal the brilliance of a single Venus. By November 1 Antares will be gone, but look for a thin waxing crescent moon to the left of Venus.

[October Star Map]

[October Moon Phase Calendar]