StarWatch: Moravian University Astronomy

MAY 2024

MAY STAR MAP | MOON PHASE CALENDAR | STARWATCH INDEX | NIGHT SKY NOTEBOOK | EVENING SKY MAP

Current Solar X-rays:

Current Geomagnetic Field:

lunar phases

1446 MAY 5, 2024: Double Diamond, Double Corona: Digital photography and the magic an older version of Paint Shop Pro, with the most recent edition of Adobe Photoshop, allowed me to composite into one image the ingress and egress diamond rings from the April 8 total solar eclipse seen from Derby, VT. Looking to either side of the diamonds, the sun's light coming from its photosphere becomes rough and blotchy. Those are Baily's beads, the last glimmer of light before totality (upper left) or the first vestiges of daylight streaming from the valleys between lunar mountain ranges found along the moon's limb (lower right). This signals the end of totality. * Then there are the prominences, the pinkish-hued features, leaping from the chromosphere, the middle layer of the sun's three atmospheric layers. They are composed of fluorescing (glowing) hydrogen gas at approximately 18,000 degrees F. trapped in a magnetic bubble. The prominences project into the sun's corona, the wispy region surrounding the sun's limb, where the temperature is at least ten times higher. Astronomers are still debating how these two thermal regions can exist side by side. Finally, the blue area, best seen near the upper left diamond, was fashioned from the diffraction and scattering of light around tiny ice particles contained in a thin veil of cirrus clouds in front of the eclipsed sun. It is also called a corona. So not only are there two diamond rings in this photo, but there are also two coronas. More pictures are below. Ad Astra!

1447

MAY 12, 2024: Cassiopeia: Ultimate Mother's Betrayal

Life in the fast lane for the highly vain Cassiopeia, Queen of Ethiopia, was going just fine until she boasted about being the most beautiful woman in the world. It was that old "Mirror, Mirror on the Wall" syndrome warned about time and time again by her therapist that started her unraveling. Specifically, it was the Sea Nymphs (Nereids) who brought about her downfall because everyone considered them to be the undisputed Sirens of the ancient lands. * The Sea Nymphs lived by lakes, rivers, and streams; some were even the attendants of Poseidon, God of the Oceans. To put it mildly, they were hot and needed plenty of water to cool down. The Nereids were rightfully angered by Cassiopeia's boasting and vowed revenge against the woman who had challenged their beauty and sexiness so audaciously. They petitioned their father, Nereus, to punish Momma Cass. He did comply by causing the ocean waters to roil into a gigantic tidal wave killing thousands as it swept across Ethiopia. However, Cassiopeia lived in her palace high on a hilltop and was spared from Nereus' actions. Cass was heard to have exclaimed, "Whatever," after learning about the tragedy. * Determined to avenge Cassiopeia's proclamation, Nereus sought his good and powerful friend, Poseidon, God of the Oceans and the brother of Zeus, to seek vengeance against the unruly Queen. Combining barnacles and brine with the foam from the turbulent waters receding from Ethiopia, Poseidon carved out a hideous, snaky creature, Cetus the Sea Monster, and set him loose along the shores of the land. There, Cetus gave chase, having a "whale" of a time, consuming fisherman and their catch, grabbing children playing by the sea, and snatching women washing clothing by the shore. * When word of the terrible creature reached Cassiopeia's palace, she disregarded her therapist's advice to repent. Instead, she sought solace from the Oracles, women responsible for giving direct and immediate answers to questions like, "What would make the monster go away?" Cassiopeia listened pensively to the Oracles' instructions to sacrifice Andromeda, her attractive teenage daughter, to the repulsive Cetus. "Whatever," Cassiopeia was heard to have whispered before she dined that evening. * Soldiers were summoned to escort Andromeda to a small island off the Ethiopian coast, where she was chained to a rock to await her fate. * "On came the sea monster, coasting along like a huge black galley, lazily breasting the waves… His great sides were fringed with clustering shells and seaweeds, and the water gurgled in and out of his wide jaws as he rolled along, dripping and glistening in the beams of the morning sun" (Charles Kingsley, The Heroes). * Little did Andromeda or Cetus know that at that very moment, Perseus the Hero was flying overhead, observing the impending catastrophe unfolding below. Consider Perseus' story appropriate for Father's Day because he would have plenty of children shortly thereafter. The winged-footed hero had just beheaded the snake-laden, granite-making Medusa and was returning to his homeland to restore order from the powerful and evil king, Polydectes. * It must have been love at first sight as Perseus swooped down to rescue the maiden. From his leather sack, he stealthily exposed the eyes of the Medusa to Cetus, instantaneously changing him into a "stoner," where he sank from sight to the bottom of the ocean and eventually helped formed a coral reef. * The story did not end well for Cassiopeia. Her few countrymen who survived, fraught with anger over the destruction of their beloved country, stormed the palace shortly after her return. Clutching Cassiopeia by her long black hair, they swung her around and around until she was pitched high into the northern heavens, where she fell into a great wooden chair with a crooked back. Destined to pivot perpetually around the Pole Star, spending half her time roped upside-down to the chair was just part of her punishment. Eternally above the horizon, ever conscious, Cassiopeia could never sleep or gain sustenance as other star patterns did when they were carried below the heavens to feast and rest. Find Cassiopeia's chair, a "W" with its bent back scraping the northern horizon by 10 p.m., and know that this story had a happy ending, except for the Queen. Happy Mother's Day. Ad Astra!

Adam Jones, who was near Devil's Tower National Monument at the time of the auroral outburst, captured this stunning image of the event against the tower made famous in the Steven Spielberg blockbuster sci fi film, Close Encounters of the Third Kind, (1977). The event continued all night.

Jon Detterline (left), Gilbertsville, PA at dawn, May 11; Natalia-Hanson-Richart (right) near Mountain Top, PA around dusk, May 10. Natalia was a student of mine during the 2022 Spring Term at Moravian University.

Peter Detterline was in Texas when these images were taken from Douglassville, PA near dawn on May 11 with his meteor camera.

1448 MAY 19, 2024: Moon to Nearly Occult Antares this Week: It was high school graduation night, June 9, 1968, and I didn't want to be there. Present were about 900 students packed into William Allen's auditorium, which was hot and muggy from the compression of people. As the standard speeches and congratulatory remarks were being given, all I could think about was getting back home and setting up my new telescope, so I could view the moon passing exceptionally close to the bright red supergiant, Antares, the alpha star of Scorpius the Scorpion. The scope's 8-inch mirror, which I had spent two years grinding and polishing, was figured into an exceptionally precise parabola with the help of Lehigh Valley Amateur Astronomical Society's master optician, Paul Shenkle. The mirror was not even aluminized, but it was installed and aligned in the Newtonian telescope that my father and I had constructed during the spring. It was ready for its first light (first observation). As I recall, the Unitron finder, a smaller telescope that provided a wide field view and, if appropriately aligned with the main scope, significantly reduced centering errors in the main instrument, had not yet arrived. However, the moon was bright and yellowish on that hazy, late spring evening and easy to find in the main instrument. Antares gleamed with a deep orange luster as Luna glided past the scorpion's heart around 10:30 p.m. They almost touched, but not quite. * That is my memory of graduation. There was no hoopla, no parties, just a 17-year-old kid whose birthday was the following day watching the moon pass a bright star. * And please don't feel sorry for me. I was not the average graduating high school teen, but for me, I was in heaven, having the time of my life, using that scope, which I still have, albeit in storage. * Antares and the full moon will be rendezvousing again on Thursday, May 23. Moonrise for Bethlehem and the Lehigh Valley in general will occur at approximately 8:57 p.m. Fifty-seven minutes later (9:54 p.m.), the moon will be closest to Antares, gliding past it according to my computer simulation, missing Luna by just under one minute of arc (57 seconds). That is extremely close. Harrisburg, PA, will experience an occultation as the moon covers Antares for a brief interval of time. * The difficulty with this observation is that the moon will be very low in the ESE at the time of its closest approach, only seven degrees above the horizon. Potential observers should seek an appropriate viewing site beforehand and use binoculars to make their observations. A piece of cardboard with a sharp edge to hide the moon might also prove helpful if binoculars are unavailable. * The exciting caveat of this observation is that the reddened light of Antares will travel through Earth's long column of air with less attenuation than its brighter, sunlit neighbor. Antares should be a little more vivid in contrast to the moon than if both objects were higher in the sky. Telescopes will have no problems viewing this near occultation from the Lehigh Valley. A computer-rendered drawing of the occultation can be seen below. Remember that Antares will be a point source and not as easily visible in the drawing. Good observing success. Ad Astra!

1449 MAY 26, 2024: How Bright is the Moon?: Anyone who enjoys sky watching knows how the moon's brightness can make or break an important observation. When the moon's brilliance is referenced, normally the luminescence of only the full moon is given, but there are huge brightness changes as Luna goes through its monthly phase cycle. Observers realize the moon's luster is primarily a function of its phases and does not greatly hinder observations between the last and first quarter when, at most, it is only half illuminated by the sun. That is because most of its surface area is still in shadow, including a significant portion of its daylight surface, where low sun angles limit brightness and, in addition, cause craters and mountains to have appreciably large shaded projections. * However, quantitative data detailing the brightness of Luna at different phases was challenging to find in an easily digestible fashion. For example, I found a graph correlating the phase angle of the moon to its apparent brightness. Phase angle can be defined as the angular distance from the Sun to the target, the moon, and back to the observer. So when the moon is completely illuminated, and its angular separation from the sun is 180 degrees, its phase angle is nearly equivalent to zero. If it were exactly zero, then a lunar eclipse would be occurring. In every case, all graphs that I found, even those detailing apparent brightness, showed no data near the full or new moon and were nearly impossible to use accurately because they were published in too small a format. I thought information regarding the moon's changing brightness, even as an average statistic, would be easy to locate, but it wasn't. * Why do I say average? The moon is a wily object when it comes to pegging its magnitude or brightness, and this is perhaps why information is not easily obtainable. Its distance from the Earth constantly changes, and Earth's distance from the sun does the same. These distance changes affect the brightness of the moon. * Anyone who has ever looked down a road illuminated with streetlights of the same intensity knows the ones farther away appear fainter than the closer lamps. The inverse square rule (Intensity = 1/distance squared) tells us that the lamp twice as far away will only appear one-quarter as bright. The size of the moon (angular diameter) also varies, with changes in distance influencing brightness. * The moon also wobbles, both east and west, as well as north and south (librations in longitude and latitude) as it orbits the Earth. Its speed varies as its distance from Earth changes, moving fastest when closest and slowest when farthest. However, the moon's rotation (spin) proceeds at a constant rate, creating a wobble in longitude. Luna's plane of orbit is tilted at an angle of five degrees to Earth's orbital plane (ecliptic), allowing us to observe beyond the moon's north and south poles, creating the latitude libration. These librations present slightly different "faces" of the moon that can be viewed with fluctuating amounts of reflectivity and, therefore, brightness. Even the location of an observer on the Earth creates a unique perspective of the moon and a slight difference in brightness. * Atmospheric extinction can also be considered because the luminescence of an object near the horizon appears fainter because the observer is looking through a much thicker column of air which attenuates more light. These are the factors in the moon's brightness that came to mind as this blog was being written. * Enter Guy Ottewell, who publishes the yearly Astronomical Calendar, which is filled with so much precise information that it is hard to imagine when this "guy" gets any rest. Ottewell started publishing the moon's varying magnitudes in his 2022 edition when Luna passed near bright stars and planets, along with the moon's angular distance from the sun. I decided to graph this information from the 2024 edition and finally produced the results I was seeking. They can be seen on the graph here with one final note. On the "Y" axis (vertical), magnitude represents the brightness of an astronomical object. It is a logarithmic scale in which a change of five magnitudes equals an intensity variation of 100. Each magnitude difference equals an intensity variance of 2.512. The moon's changing brightness awaits your scrutiny. Ad Astra!