StarWatch: Moravian College Astronomy

StarWatch for the greater Lehigh Valley

OCTOBER 2007

OCTOBER STAR MAP | STARWATCH INDEX | MOON PHASE CALENDAR

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

Solar X-rays:
Geomagnetic Field:

Status

Current Moon Phase

581 OCTOBER 7, 2007: Heroes: Do you have any heroes or people you really admire? I believe individuals who are held in esteem are a necessary ingredient to one’s successful journey through life. In my own case these persons have helped me to maintain focus, balance, and motivation. They range from Dieruff Junior, Julyssa Nunez, to moonwalker, Buzz Aldrin. Their contagious spirits for life and learning encourage me to teach. Also among my heroes is astronomy popularizer, David Levy, who will be appearing on Saturday to speak in celebration of the 50th anniversary of the Lehigh Valley Amateur Astronomical Society at Iron Lakes Country Club in Orefield. I was introduced to Levy through an AP photo, years ago, showing a man surrounded by his 100 plus telescopes. “Wow,” I mused. Then I got to meet and talk with David when he accompanied Pluto discoverer, Clyde Tombaugh, through the Valley in 1987. By this point Levy was published and had discovered a half dozen comets. Levy’s devotion to an elderly Tombaugh, his passion for astronomy, and his humility made an everlasting impression upon me. David Levy went on to co-discover the comet that crashed into Jupiter in July of 1994, Shoemaker-Levy. That single event propelled him to global fame and spurred professionals to begin scouring the solar system for objects that could strike the Earth. Hundreds have since been discovered. In 2002 when my students and I met Levy for a quiet evening of observing at his suburban Tucson home, I was again inspired to witness that notoriety had not dampened his astronomical passions nor transformed his humility. Readers who would like the opportunity of meeting and hearing David Levy speak can reserve banquet tickets by contacting Melody Gardner at 610-844-6931.

582 OCTOBER 14, 2007: Venus Dawns Bright: I have received many queries since the beginning of the school term about that brilliant beacon of light in the east at the day’s start. It is the planet Venus, enveloped in reflective sulfuric acid clouds, with an atmosphere 90 times heavier than Earth’s ocean of air. Poisonous carbon dioxide, seething at a hellish 900 degrees Fahrenheit, comprises the bulk of the Venusian atmosphere. Truly, the Goddess of Love’s beauty is only skin deep. At some time during my high school astronomy course, I’ll jokingly tell my male students to be wary of women like Venus. “They’ll crush, fry, and poison you, then spit you out, so that they can do it all over again.” If I can get my female audience to protest vehemently, I’ve been successful. At least I know that everyone is processing. Venus left the scene in late August when it set during twilight in the west. Shortly thereafter, it passed between sun and Earth to appear in the east before sunrise. By early September, Venus could be spotted near the horizon in a brightening dawn sky. Venus has since gained altitude as it has pulled away from the sun to become visible to virtually anyone who is outside looking east at dawn. Its brightness still astounds me, no matter how often I have seen it. However, this week Saturn adds an extra sparkle to dawn’s early light, appearing just to Venus’s left at the beginning of the week, and between Venus and the bright spring star Regulus of Leo the Lion by the end of the week. Regulus, the 22nd brightest star of the night sky, will be about half the brightness of Saturn, but over 200 times fainter than Venus, so these three diamonds will have spectacularly different carat values. While you’re out taking in the morning air, don’t forget bright Mars which will appear orangey-white, high in the south in the constellation of Gemini.

583 OCTOBER 21, 2007: Mars on the March: Remember how bright Mars was in the summer sky of 2003? Earth passed within 34.65 million miles of the God of War on the morning of August 27, our closest approach to Mars in 60,000 years. Earth was close to Mars again in late October of 2005, at a distance of 43 million miles. Now just over two years later in December of 2007, Earth will again be passing the Red Planet, this time at a distance of 55 million miles on the afternoon of December 24. Christmas Eve will find the Red Planet, dazzling in the east less than a degree away from the full moon. Orangey Mars will be the second brightest object in the heavens that night, adding an element of celestial glitter to the copious outdoor lighting celebrating the Holidays. Currently, Mars is in the constellation of Gemini the Twins about 20 degrees south of the zenith at dawn, but it will soon be visible to us during the early evening hours. By November 1, Mars rises at 8:30 p.m.; mid-November 7:45 p.m.; early December, 6:30 p.m.; mid-December 5:00 p.m.; and early January, 90 minutes before sunset. Presently, Mars will pass south of the third magnitude star Mebsuta, where the short stubby legs of Castor, the mortal Twin, join. As we move into November, Mars’s march towards the east will slow and become stationary just to the east of Mebsuta on the 15th. Then the Red Planet begins to retrograde towards the west passing less than a half degree to the north of Mebsuta on the evening of December 3rd. Mars completes its backwards loop in Taurus at the end of January 2008 within 2-1/2 degrees of the star Elnath, the tip of Taurus the Bull’s northern horn. Mars will be an added gem in the west during the total lunar eclipse of Wednesday, February 20, along with ringed Saturn, which will be less than three degrees from the moon’s reddened glow.

584 OCTOBER 28, 2007: Comet Holmes Explodes in Brightness: Like a bolt out of the blue, a faint comet visible only in the largest of telescopes has suddenly brightened by over 600,000 times to become visible to the unaided eye. The event unfolded on October 24 in less than a day, as Comet 17P/Holmes literally seemed to explode from inconspicuousness to one of the brightest northern hemispheric interlopers of the last decade. Comet Holmes was discovered by British astronomer Edwin Holmes on November 6, 1892, when a similar outburst occurred. After that eruption, the comet’s brightness dimmed very slowly, remaining visible to the unaided eye for three weeks. During this interval the coma, or central region of the comet, expanded rapidly, reaching approximately the size of the full moon before it faded against the starry background. A similar scenario seems to be unfolding with the current outburst. Astronomers in late January of 1893, however, were treated to a second outburst which rivaled Holmes’s initial brilliance. Currently, Comet Holmes is yellowish in hue and about as luminous as the stars of the Big Dipper. It is located in the constellation of Perseus about mid-sky in the ENE by 9 p.m. Binoculars will enhance the comet’s brightness and perhaps allow observers to get a glimpse of its growing dust tail during the week. Use the URL below and go to “this week’s StarWatch” to find a 9 p.m. locator map for Comet Holmes. Observe before moonrise to afford the darkest possible sky conditions. Moonrise occurs about 8 p.m. Monday. By the end of the week, a fainter waning crescent moon doesn’t rise until 1:30 a.m. Comets are loosely packed aggregates of dust and ice which can fracture easily. Such a split could have released the necessary materials to have precipitated the comet’s rapid brightening.

[October Star Map]

[October Moon Phase Calendar]