StarWatch: Moravian College Astronomy

StarWatch for the greater Lehigh Valley

OCTOBER 2014

OCTOBER STAR MAP | MOON PHASE CALENDAR | STARWATCH INDEX | NIGHT SKY NOTEBOOK

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946 OCTOBER 5, 2014: WARNING: Excessive Tiredness May Result: Not every astronomical event is convenient, so it might take a little effort to rise and shine early on the morning of October 8 to see the total lunar eclipse. For me it will probably require a sleepless night just so that I’m conscious enough to drink in the beauty of Wednesday morning’s eclipse. A total lunar eclipse happens when the moon passes completely into the Earth’s shadow or umbra. Since the center of the umbra is exactly opposite to the sun, a total lunar eclipse can only occur when the moon is also opposite to Sol or in its full phase. Tuesday evening begins with the nearly full moon rising not quite 30 minutes before sunset which occurs around 6:30 p.m. While the Earth’s rotation carries brilliant Luna across most of the heavens during the night, the moon’s orbital motion will position it ever closer to Earth’s shadow. First contact with the umbra occurs at 5:15 a.m. EDT, with the moon low in the west, but keen observers will notice that the region of the moon closest to the shadow will appear dusky about 20 minutes earlier. During the next hour and nine minutes, the moon marches steadily into Earth’s shadow as twilight conditions begin to overtake East Coast observers. Totality begins at 6:24 a.m., EDT with the moon just seven degrees above the western horizon. Moonset occurs about the same time as sunrise, 7 a.m., when Luna has just passed mid-eclipse. Observers farther west get to see more. In the Central Time Zone, enthusiasts will view all of totality, while regions in Mountain Daylight Time get to witness Luna depart Earth’s umbra before moonset. West Coast observers, including Alaska and especially Hawaii, are in the optimal locations, but views of totality, which often reveal yellows, oranges, and reds if the eclipse is vibrant, could be spectacular from the East Coast in a brightening blue morning sky. So ready yourself for a few yawns on Wednesday if the weather cooperates.

947 OCTOBER 12, 2014: In the Dark of the Night: I remember when my wife, Susan and I got “trapped” in Sennefer’s tomb, in the Valley of the Nobles near the Nile River’s West Bank at Luxor. Sennefer was mayor of Thebes during the reign of Amenhotep II (18th Dynasty; 1427-1401 BC). The tomb guard, equipped with only a kerosene lantern, disappeared upstairs for “just a moment,” and my wife and I were left in total blackness and silence for what seemed to be an eternity. It probably was no more than 10 minutes, but we were in the heart of Egypt’s greatest necropolis, and that had to be the scariest darkness I have yet experienced. The night sky is never that black, for stars, planets, and even the sky itself gives off a sufficient amount of light for the fully dark-adapted eye to distinguish a myriad of details on the ground. So how dark can it get? In New Mexico and Utah, where I have done most of my summer observing, I have regularly noticed shadows being cast when Venus was visible in the sky. I had read about Jupiter being able to accomplish this same feat, but it was not until August 2000 that I got to make that observation from Chaco Canyon, NM. High in the eastern sky about 4:30 a.m. was Jupiter, Saturn, and the winter group of constellations rising over North Mesa. What a glorious sight! My shadow was plainly visible on the ground pointing away from Jupiter. Astronomers say the darkest skies in the world occur in the Australian Outback where the Milky Way is so brilliant that it can cast diffuse shadows on the ground. I witnessed this for myself in the Australian Bush at Siding Spring National Observatory in February of 2001. Not only did the brilliant southern Milky Way provide enough illumination to discern ground detail easily, but I was also able to read the lettering on my Mt. Washington sweatshirt. Turning away from the Milky Way made the lettering indecipherable. Night darkness I can handle, but keep me away from the blackness of those tombs.

948 OCTOBER 19, 2014: Seeing Double: Binary and multiple star systems are all around us. In fact, astronomers feel that slightly more than half of the stars that we can see with the unaided eye have one or more companion stars orbiting them. Take into account a general survey of all stars in the sky and it is believed that the numbers divide pretty equally between binary/multiple star systems, stars with one or more planets/brown dwarfs, and solitary stars existing by themselves. Most gravitationally bound systems require some type of telescopic aid or other more sophisticated techniques to be revealed, but a few can be seen with just the naked eye. My favorite system for this time of the year is the double-double found in the constellation of Lyra the Harp. The alpha star is brilliant blue-white Vega about 26 light years distant. It is currently the brightest star near the zenith right after darkness. A majority of the pattern is composed of five additional stars, four of which form a parallelogram, the location where the imaginary strings of the harp are strung. The fifth star, Epsilon Lyrae, is detached from that grouping, but it is positioned as near to Vega as the closest member of the parallelogram. To the average sighted observer, Epsilon Lyrae appears as a single star, but to a person with better than normal vision it can be split into two stars which appear equally bright. I only split it once on a very dark and transparent night back in the late ‘60’s; however, it’s easy to see its duplicity with binoculars. Their separation is only 208 seconds of arc or about 1/17th of a degree. The moon is nine times the angular separation of Epsilon. What’s more fascinating is that each of the stars that compose the double is also a double, but a telescope with a 4-inch lens or mirror and a magnification of at least 100 is needed to split them. Even one of the double-doubles is double. I’m getting confused. All of these stars spin rapidly, so there are no planets for this system. Photos are online at astronomy.org.

949 OCTOBER 26, 2014: Planet Insanity: I was recently in attendance at a talk by Dr. Carlson R. Chambliss, with whom I worked at Kutztown University for many years. The talk highlighted Pluto’s demotion as a planet, but a subtext of that lecture was a digression about how the number of planets has changed over the centuries. Go back to the Greeks, and anything that was a wanderer was considered a planet. Included were the sun and the moon, but not the Earth. There were seven planets in antiquity. Fast forward to 1543 when Copernicus, the Polish astronomer, revitalized the early Greek concept of a sun-center universe. Now the planets numbered six—Mercury through Saturn, including the Earth. In 1781, the musician-turned-astronomer, William Herschel, discovered Uranus and increased the planetary fold to seven. When Giuseppe Piazzi discovered the first asteroid in 1801, there were eight, but by 1807 that number had jumped to eleven when additionally Pallas, Juno, and Vesta were added to the planetary lineup. In 1846 the German, Johann Bode, found Neptune after being mathematically predicted by John Adams (English) and Urbain Le Verrier (French). By 1851 with more asteroids in the mix, the total number of planets had risen to 31. The planetary entourage was becoming increasingly confusing until the Royal Astronomical Society of England said, “Enough!” and reduced the number of planets to eight in 1852—Mercury through Neptune. When Pluto was discovered by the American, Clyde Tombaugh, in 1930, we had our ninth planet, but it was simply too small. Controversy erupted in the twenty-first century as other trans-Neptunian objects were found, and one TNO, Eris, was discovered to be larger than Pluto. The debate was finally settled in 2006 by the International Astronomical Union which demoted Pluto and created a new type of solar system object called a dwarf planet. Dr. Chambliss voted “yes” for Pluto's demotion.

[october Star Map]

[October Moon Phase Calendar]