StarWatch: Moravian College Astronomy

NOVEMBER 2017

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

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lunar phases

1107 NOVEMBER 5, 2017: Action Figures Dominate Fall Sky: A few weeks ago when the moon was near its new phase, I wrote about how to find the Andromeda Galaxy. The star pattern of the teenager, Andromeda, the daughter of evil Cassiopeia, Queen of Ethiopia, hangs onto Pegasus the Flying Horse as she is being conveyed to the kingdom of Polydectes, on the island of Seriphos, and away from imminent death. There, Perseus the Hero, rescuer of Andromeda, will change Polydectes and his court into stone with the head of the Medusa who he has just slain. The “snake-beheaded” Medusa, one of three Gorgon monsters, was so scary that simply looking into her eyes metamorphosed the viewer into stone. Perseus then assumes his rightful place as king, marries Andromeda, has lots of kids, and lives happily ever after. Sounds like the making of a Hollywood blockbuster, and indeed the story has been told several times on the big screen in two versions of Clash of the Titans (1981 and 2010). The perpetrator of these malevolencies in the mythology is Cassiopeia who plays the old “mirror, mirror on the wall” game and truly believes that she is the fairest of them all. This starts a whole sequence of events that first infuriates Nereus, who is the father of the Sea Nymphs. The Nereids are considered by man and god to be the most beautiful women in existence. A storm and tidal wave sent by Nereus does little to persuade Cassiopeia to quit her offensive behavior and that sets Nereus to ask his good friend Poseidon, God of the Oceans, to take care of the matter once and for all. Poseidon conjures up a sea monster called Cetus the Whale to ravage Ethiopia. Hollywood ramped up the excitement by substituting the Kraken for Cetus, a really hideous creature. The Kraken does get Cassiopeia’s attention. The oracle that she consults to vanquish the monster declares that she should offer Andromeda as a sacrifice. Cassiopeia complies without hesitation. Meanwhile another mythology is unfolding with Perseus trying to slay the Medusa, a ploy that Polydectes has devised to get rid of Perseus permanently, so that he can marry Perseus’ beautiful mother, Danae. Perseus decapitates the Medusa with the help of Hermes (Mercury) and Aphrodite (Venus), putting her head into a sack; but on the way home, airborne Perseus gets blown off course by the terrible storm Nereus has wrought against Cassiopeia. The skies clear for Perseus just as Cetus is about to devour Andromeda. You’ve got to know what happens next. Cetus is “stoned,” Andromeda rescued; Perseus and Andromeda return to Polydectes’ court where a lot of limestone statues are created. All of these action figures are on display this week in the NE right after it gets dark. A map can be found below. Look for the sideways “W” in the sky which represents the upside-down chair Cassiopeia was thrown onto by the angry survivors of Ethiopia. Perseus rises below Cassiopeia, and Andromeda and Pegasus are high above and to the right. Good observing!

1108 NOVEMBER 12, 2017: Leonid Meteors Fly this Week: November traditionally represents the transition period from tolerable warmth to the chill of winter. By the time of Thanksgiving, accumulating snows can already be in the forecast. Some of the best meteor observing occurs during the long dark nights of late fall and early winter, and with a cooperating moon, these events can be impressive. If the sky is clear, the morning hours of November 18 (Leonids), December 13 (Geminids), and 22nd (Ursids) all promise to deliver a plethora of shooting stars. The moon certainly will not pose any problems. It was the Leonid shower of November 12-13, 1833 that gave birth to meteor science. During the four hours preceding dawn on the 13th, meteors rained down on the eastern and central US, with as many as 15-50 shooting stars visible each second, radiating away from the head of Leo the Lion. Screams of hysteria as well as the bright, but silent explosive flashes of light from fireballs illuminating bedroom interiors awakened most people in the regions of greatest activity. A 24-year old Abraham Lincoln was an eyewitness to the Leonid storm that morning. The Leonids are cyclical in nature with increased activity occurring every 33 years or so. The last interval of enhanced action was between 1998 and 2002, but the Leonid meteor shower of 1966 was also a banner year in the Southwestern US with rates as high as 40 to 50 meteors per second visible over a 10 to 15-minute time interval. Leonid meteors result from the abundant dross which is released by Comet Tempel-Tuttle, discovered December 19, 1865 by E. Tempel (French) and independently on January 6, 1866 by H. Tuttle (American). As the short period comet swings around the sun every 33.17 years, dense corridors of debris are released from sublimating (vaporizing) ices that compose most of the comet. Earth intersects the denser swarms of powdery dust near to Tempel-Tuttle in enhanced periods of activity when the comet is close to the sun. Particles in these debris streams rapidly disperse so that in an average year like 2017 about 10-15 Leonids will be seen each hour after midnight on maximum morning. Want to be a part of meteor history? Then be outside, warmly dressed around an hour or two before dawn on November 18. Leo will be high in the sky, just west of south. Leonid meteors are the swiftest of the major showers, entering the Earth’s atmosphere at slightly over 43 miles per second. They will appear to be radiating from the sickle of Leo the Lion, a backwards looking question mark which forms the Lion’s head and lower torso. The bright star Regulus forms the dot of the question mark. Leo can be bisected by taking the two stars of the Big Dipper that point to the North Star, Dubhe and Merak, and going in the opposite direction about an equal distance. A Leonid meteor will appear to be radiating swiftly away from the head of the Lion every five minutes or so. A map is online at astronomy.org.

1109 NOVEMBER 19, 2017: Robotic Observatory Becoming a Reality: The Mars Desert Research Station (MDRS) Robotic Observatory which Moravian College has a 25 percent buy-in share is now standing proud at the MDRS facility near Hanksville, Utah. It is still not operational, but I wanted to give the Moravian community an update on its progress. This past spring, a site was chosen and the concrete foundation for the structure was poured. All of equipment was finalized, purchased, and plans were put into motion during July to complete the installation of the observatory, high-speed Internet connectivity, and test the mounting system of the two telescopes and their cameras. There were many complications that delayed this timeline, but a host of incredibly generous people stepped forward to help. We could not get a firm arrival date for the observatory because Hanksville, with its 203 residents, was not a large enough community for regular freight delivery. Curtis Construction of Hanksville traveled to Lake Havasu City in western Arizona and picked up the observatory for us. They also trenched the electrical lines, placed and buried the wires so the observatory could be electrified and made operational for off-line testing. Adam Jones, an IT expert who lives in Denver, dropped by and succeeded in interfacing the observatory computer with our laptops so that it could be opened and closed remotely. Then Ed Thomas of Deep Space Products (Tucson) arrived with the mounting system and telescopes, but minus one of the two cameras. The summer 2017 cyber terrorist attacks in Europe had affected the ability of the Czech Republic company making the CCD cameras, Moravian Instruments (yes, that’s the real name) to ship on time. Ed Thomas helped us assemble the mount, but we did not attach the two telescopes because without all of the additional equipment onboard, and a balanced system, nothing would work anyway. In addition, HughsNet, the only Internet provider for the Hanksville area, failed to hook up the high-speed system. Lead astronomer, Peter Detterline along with Ed Thomas returned to Utah in mid-October and worked out most of the kinks, in a grueling 10-day period, but the main camera for the larger research telescope malfunctioned and has since been returned to the Czech Republic for repair or replacement. In addition, we have not been able to access remotely the mount which moves and positions the telescopes due to a quirky power switch. There are fixes to this issue which are currently being pursued. If the Moravian camera arrives back in time, Peter Detterline and I will travel to Utah over the Winter Break to get the observatory and telescopes operational. Wish us success! Find pictures at http://astronomy.org/StarWatch/November/index-11-17.html#11-19-17.

1110

NOVEMBER 26, 2017: Lunar Phases Confusing

The moon this week dominates the nighttime sky. Sunday begins with Luna positioned high in the south at dusk at its first quarter phase. Even though the moon appears to be half on and half off with the light to the right, it has only traveled to a position which is 90 degrees to the east of the sun. Therefore, it has only completed one quarter of its phases and stands at first quarter. Jennifer Warnes got it right in her popular song, Right Time of the Night (1976) when she crooned, “Sun goes down on a silky day, quarter moon walkin’ through the Milky Way.” Another quarter phase repeats itself about two weeks later, when the moon returns to an angle of 90 degrees from the sun, and is again half on and half off. This time it is illuminated from the left. The moon has reached its last quarter or third quarter phase. Both terms are correct, but I prefer last quarter because the light is to the left in a last quarter moon—the three “L’s.” Since the moon’s new phase on the morning of November 18, Luna first looked like a snippet of a fingernail in the early evening sky, but gradually waxed each night, growing brighter until it reached first quarter. During this period the moon was a waxing crescent. The word crescent means to be the shape of a single curve that is broad in the center and tapers to a point at each end (Oxford) or more simplistically, to have horns, like a crescent roll; the word wax means to grow or increase. A first quarter moon is also waxing because immediately following this specific one-night phase, the moon becomes a waxing gibbous for about six evenings. Gibbous simply means to be convex or protuberant (Oxford), bulging on both “sides.” The one outward bulge marks the limb or boundary of the moon against the sky, while the other bulge results from the moon’s terminator, the location where if you were on the moon, the sun would be rising or setting. What is causing this changing parade of light on the moon? It is simply sunlight reflecting off its surface as Luna orbits the Earth. What we are witnessing is the moon revolving (orbiting) around our planet and cycling through day and night. By December 3, Luna will be in opposition to the sun and in its full phase, rising at sunset and setting on the following sunrise. Afterwards, the moon begins to wane or decrease in reflected luminescence; a waning gibbous for about six days, last quarter moon (one night), and finally a waning crescent for another six days before reaching its new phase and repeating the cycle. These concepts may seem elementary, but they are not as simple as they seem. One of my Dieruff students, Elizabeth O. Evans (2007) came up with the phrase, “You always wax your car before it ‘wanes,’” but the words waxing and waning are archaic in our modern-day usage of English and the association of a quarter moon when it is half illuminated visually is also more complex than it seems. The most difficult concept for students to grasp is that watching the moon cycling through its phases is simply an exercise in observing the moon’s day and night sequence, which takes about one month (moonth—not a real word) to complete 29.5 days.