StarWatch: Moravian University Astronomy

APRIL 2025

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lunar phases

1494 APRIL 6, 2025: Sun Pillars: Driving home from Lowe's in Quakertown on March 24, after picking up supplies for my observatory, I decided to take a less stressful way via a back road to avoid the more congested Route 309. The sky was mostly clear, and the cooling air was very moist from a recent shower. * Driving northbound, I noticed a haze layer swiftly developing just a foot above the rapidly cooling ground. At the same time, I caught the sun setting behind a grove of skeletal trees, a Kodak moment for sure. I got the picture. Then, the real surprise developed as I continued homeward: a solar pillar emerged, one of the finest I have ever seen. I drove past houses, unsightly distant telephone poles, and other obstructions I did not want to have in my image's foreground until I was able to turn into a church parking lot along with hundreds of other people all staring in the wrong direction. Yes, it was a cemetery where I captured the picture below. * Solar pillars are generally formed by thin plates of hexagonally-shaped ice crystals slowly falling through the air in near horizontal positions. Think of how a broad maple leaf flutters towards the ground in calm air during autumn. That is how these thin-plated crystals are moving as they gently descend, rocking back and forth, the sun's light reflecting off the crystals' relatively smooth surfaces, sending its light back towards Sol, creating the pillar that can be observed above it. There are several iterations of sun pillars, as explained in Robert Greenler's Rainbows, Halos, and Glories, Cambridge University Press, 1980, but from my readings of his text, I think this most common explanation fits the bill for the pillar that I witnessed. Ad Astra!

1495

APRIL 13, 2025: Serendipity

While talking the other day with Dr. Keith Wood, Assistant Professor of Practice in Physics, who came to Moravian in 2022, a remarkable coincidence evolved in our discussion. Wood received his BS and MA from Northern Arizona University in Flagstaff. As a graduate student, Wood and a colleague, David Koerner, researched low-mass stars and brown dwarfs at Lowell Observatory. Wood explained, "The idea was that widely separated [low mass] binary systems would appear to have a common proper motion, so with sufficient time between observations, we could identify candidate systems. Since few low-mass stars had distances known via parallax at that time, we could potentially learn a lot about the nearby stellar neighborhood." * Historically, Lowell was the first US observatory site tested before its founder, Percival Lowell, commissioned Alvan Clark and Sons to construct a 24-inch aperture refractor in 1895. It was here that Lowell and others popularized canals and life on Mars. Clyde Tombaugh discovered the planet Pluto, now a dwarf planet, at Lowell in 1930, while the work of Vesto M. Slipher (1912-14) found the universe to be expanding. * Somehow, our conversation shifted to eclipses because it had been virtually a year since the April 8, US eclipse had transpired. Wood's two young twins prevented him from seeing it, but the chat continued something like this: Becker: Did you see the 2017 August 21 total solar eclipse?
Wood: Yeah, I did.
Becker: Where?
Wood: Wyoming... I had just completed my PhD at Auburn (Alabama) University when I received the opportunity to view it.
Becker: Where in Wyoming?
Wood: Eastern…
Becker: Me too! I volunteered with a friend, Pete Detterline, in Guernsey State Park for the Wyoming Park Service. We were up by the yurts.
Wood: Me too!
Becker: This is crazy. Were you in the yurt section of the park with the University of Hawaii group, which was right next to my group, with telescopes and cameras in a large tent-like enclosure?
Wood: That was us!
Becker: Unbelievable… We were probably no more than 250 feet apart from each other for three or four days. I probably walked right past you numerous times because I was curious about what your group was doing.
Wood's doctoral work involved a better understanding of identifying turbulence in the Earth's magnetosphere with the eventual ability to predict when a geomagnetic storm might disrupt communications and power grids and require protective protocols to be taken by satellite operations to avoid damage. Wood was not even slated to be with the University of Hawaii party except for another series of extraordinary circumstances that involved several peer recommendations that propelled him to the forefront after another individual was unable to commit to the Hawaiian group. * This type of serendipitous meeting is the fourth time in my life that the entanglements of my existence have led to these extraordinary encounters. The most complex series of circumstances was how I met my wife. Ad Astra!

Keith Wood, working with the University of Hawaii's eclipse team was less than 100 yeads from where I observed the August 21, 2017 total solar eclipse from Guernsey State Park in Guernsey, Wyoming. This picture was taken on the morning of the eclipse. Gary A. Becker image...

1496 APRIL 20, 2025: Meteor Activity Resumes wtih the Lyrids: Although the Quadrantid Meteor Shower marks the first major shooting star event of the New Year, it symbolizes the end of the primary meteor season that started with the Delta Aquariids in late July. I have been to some of the darkest locales in the world multiple times, in Australia, during the January to April meteor lull, and I do not remember seeing a single shooting star streak across the black austral skies. * After this three-and-one-half month pause, mid-April marks the initial spark of activity, with the Lyrid Shower typically providing the first decent rates of the season. * Comet Thatcher (C/1861 G1 Thatcher), a long-period interloper that requires 415 years to navigate its solar orbit, is responsible for the display, one of the oldest witnessed annual meteor events in astronomy. Chinese records date the first observation to 687 BCE. * The dust from Thatcher's tail intersecting Earth's orbit when we are at that position in our circuit around the sun, triggers an increase in the April rate of shooting star activity. The radiant is the undisputed indicator that these Lyrid meteors are related. The larger silicate particles released by the nucleus in a comet's outgassing processes follow the comet's orbital path as it warms from the sun's radiation. These particles move parallel to each other, so that when they enter the Earth's atmosphere, they appear to diverge from a small region in the sky called the radiant. The analogy is similar to a long stretch of roadway that appears to diverge from a vanishing point far off into the distance. * Even though it is spring, Lyrids emerge from a location that can be traced back to a part of the summer sky near the constellation of Lyra the Harp and its principal star, Vega. * When observing just after midnight on Tuesday, April 22, the radiant will be approximately 30 degrees in altitude and 15 degrees to the right and above Vega, a brilliant blue-white supergiant, radiating energy at approximately 70,000 times greater than our sun. Don't expect to view many Lyrids until the radiant reaches a respectable distance above the horizon. By 2 a.m., Vega is mid-sky in the east. Meteors rates are predicted to be about 5-10 events per hour. Activity may increase somewhat towards dawn. This year's lower than normal rates are attributable to the maximum activity occurring around 11 a.m. on the 22nd for the East Coast. The 37 percent waning crescent moon will not rise until 3:30 a.m., about an hour before dawn begins to brighten the sky. If you are observing at that time, keep the moon outside of your field of view. * To observe Lyrid meteors, face east after 11 p.m. Dress for winter weather, comforted by a warm sleeping bag and pillow. Gaze straight up at the zenith. This area of the heavens is usually the darkest region of the sky in a suburban or urban location. Lyrids will seem to trace back close to Vega. Don't let the morning stillness and the springtime air put you into a deep sleep, because sometimes Lyrid showers have outbursts of activity. * Good observing for the first of a handful of major meteor events that will grace the skies over the next eight months! For a map of the Lyrid radiant, please look below. Ad Astra!

1497 APRIL 27, 2025: May Day: My father was born on the Celtic festival day of Beltane, May Day, May 1, 1919, but it would take me into my teaching days before I realized its astronomical significance. We all knew about the Celtic celebration of Halloween, commemorated on the final day in October, when the veil that was supposed to divide the living from the dead thinned to where it was possible for the spirits of the underworld to pass into the realm of the living. Then there was Candlemas, celebrated on February 2, which had Christian roots and represented the presentation of Jesus at the Temple in Jerusalem by Joseph and Mary, as well as the time when candles to be burned during the course of the year were blessed, again representing Christ as the light of the world. * The secularization of Candlemas in Europe and America produced Groundhog Day, where the burrowing badger or groundhog had a predictive understanding of the beginning of springtime by examining the bourgeoning roots in its underground dens. Finally, there was Lammas Day, on August 1, also known as Lughnasadh, another Celtic festival where the sun god Lugh was wedded with the Earth, commemorating the ripening of crops and the first harvest of the summer wheat. * What did all of these holidays have in common, astronomically? They represented the cross-quarter days, the midpoints between the solstices, the high and low sun, and the equinoxes when the sun was positioned over the Equator: February 2, May 1, August 1, and October 31. * If Halloween represented the defeat of death for yet another year, then May Day was in tribute to the rebirth of life, love, and fertility after the passing of the dark, cold winter season. In medieval Europe, celebrations involved fairs and feasts. The youth of small villages gathered at sunrise in the town square to choose a young girl who would become the "Queen of the May." Her young admirers transported the queen, decked with a garland of flowers, by cart in parade-like fashion to the maypole, which has become synonymous with celebrating this cross-quarter day. The pole, painted in bright colors, had long ribbons attached to it. Celebrants would take hold of the colorful streamers, singing as they skipped and danced around it, wrapping the ribbons tightly around the pole until the raucous participants came together in a large heap of humanity. * Ironically, in the 1950s, to culminate the end of the Allentown School District's playground season, the maypole activity was the concluding event, as scores of groups from all over the city gathered at the Allentown Fairgrounds to celebrate the end of another summer. Someone got their Beltane and Lammas celebrations confused. We are now halfway to the summer solstice. Hallelujah! Ad Astra!