StarWatch: Moravian College Astronomy

StarWatch for the greater Lehigh Valley

MARCH 2021

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1281 MARCH 7, 2021: Moravian’s Sky Deck Refurbished: Back in 1978, when friend, Peter Detterline, first observed the winter heavens from the Sky Deck with his brother, Jim, who graduated from Moravian that same year, the two had to climb an icy, 16-foot vertical ladder to gain access to the observing space. No wonder, Dr. Joseph Gerencher, who envisioned the area for astronomical and meteorological instruction, kept telescope gear very portable. The space was also used by Jim Detterline and friends as a high spot for repelling because it had no railings surrounding it. Those were the “good old days” when life was less litigious, and one never thought about taking someone to court if a mistake resulted in a fall from a four-story height. • Over the intervening 30 years before I came onboard in 2010, Joe did a spectacular job of creating a sanctuary under the urban heavens upon the highest accessible location to students on campus. A safe, metal stairway was constructed; a wrought iron railing was installed around its perimeter, and the deck was padded to preserve the flat roof. Joe installed concrete stanchions (blocks) on which the telescope piers were encased and storage containers for the telescopes and mounts when not in use. Through outright purchases and donations of equipment from the local astronomy community, the College continued to enhance the number of telescopes available. One of the most innovative aspects of what was then called the Collier Rooftop Observatory was Joe’s design and construction of two enclosed aluminum caps that pivoted off a small platform on which the telescopes were mounted. These were secure against the unique high wind conditions that sometimes plagued the deck which was above the campus tree line. • Because of their variety, the telescopes made the Sky Deck’s use very teacher-centered, with students being mostly observers, queuing behind the eyepiece. In addition, campus and Bethlehem light pollution increased, making the sky more devoid of stars, and more difficult to find astronomical objects manually. • In 2015, David Fisherowski of Boyertown came to Moravian’s rescue by donating a series of telescopes and computerized mounting systems that all functioned in a similar manner. This allowed me to teach students how to operate these mounts in a more efficient manner. Learners became active participants in conquering the heavens. Chair, Kelly Krieble, also opened up the Physics Department’s coffers to help to purchase more used equipment so that only four students would be assigned to each scope. In addition, $20,000 was raised through public donations to support improvements on the Sky Deck space. • Initially, students had to transport all of their equipment from my basement lab, set up and align the telescopes to Polaris, then calibrate their scopes to six reference stars before beginning to observe. That was very time-consuming. As Moravian acquired heftier mounting systems, telescopes were tarped and remained on the Sky Deck through the temperate months. Unfortunately, a few were blown over in spring windstorms that saw gusts in excess of 70 mph rake the rooftop. This past summer, the old piers were removed from their stanchions, and new ones fabricated and installed. Larger telescopes now remain secured and tarped ready for use on any clear night throughout most of the spring and fall semesters. • Today, when I take my students on their first visit to the Sky Deck, I show them one of the vertical ladders that is still present on another nearby roof structure. There are always expressions of disbelief that just 40 years ago the conditions here were so primitive, that this observing space was accessible only to the intrepid. Pictures can be found below.

MARCH 14, 2021: Moon Shadow Alert: April 8, 2024

It’s just over three years into the future, but I am already receiving emails about this event. The continental US will host another total solar eclipse on April 8, 2024. Instead of the moon’s shadow traveling across the United States from west to east like it did in 2017, this eclipse will split the county in half, with darkness sweeping northward from Mexico, through Texas, Arkansas, Missouri, southern Illinois, Kentucky, Indiana, Ohio, northwestern Pennsylvania, western New York, northern Vermont and New Hampshire, and Maine. The cities and communities of Watertown, Rochester, and Buffalo, NY; Burlington, VT; Erie, PA; Cleveland, OH; Indianapolis and Evansville, IN; Little Rock, Hot Springs, and Texarkana, AR; Dallas, Ft. Worth, Waco, Austin, and San Antonio, Texas all lie within the path of totality. • There will not be another total solar eclipse that will touch the continental US until August 23, 2044 and an eclipse that will crisscross the US until August 12, 2045. Unlike the August 21, 2017 eclipse that produced a maximum of 2 minutes, 40.2 seconds of darkness, the 2024 eclipse will allow Texans to witness as much as 4 minutes, 26 seconds of totality while Mainers get to see the sun hidden by just under one minute less. • Umbraphiles, those individuals who are eclipse afficionados and want the maximum time in the shadow of the moon, will have to travel 5 miles south of Bermejillo, Mexico located about 410 miles to the southwest of the Texas border. At the location of greatest duration, totality will last 4 minutes, 28.1 seconds. For the longest duration in the US, just over the Rio Grande, the centerline passes about 7 miles to the north of Elm Creek, Texas. The Maverick County International Airport along Route 277 marks the spot. That location will experience 4 minutes, 26.9 seconds of totality. That is a luxury compared to the 2 minutes, 22 seconds of moon shadow that I experienced in Guernsey State Park in eastern Wyoming in 2017. • For those individuals who want to see a total solar eclipse with less drive or fly time, concentrate on Watertown, Rochester, or Buffalo, NY; Erie, PA; Cleveland, OH; Indianapolis, IN; or Carbondale, IL, all within a day’s road travel from the Lehigh Valley, and all seeing more than 3 minutes, 35 seconds of umbral shade. These cities, except for Indianapolis, lie very close to the centerline. • A negative feature of the Midwest to Northeast locales is the weather. If conditions are inclement at one location, they could be bad at all locations, since frontal systems often orient themselves in a southwest to northeast direction. Temperatures will also be chilly, especially in the Northeast. • Why write about an event so far in advance? Total solar eclipses can be that spectacular, even life changing. That is why this event will be my 11th central solar eclipse. The Lehigh Valley sees 92 percent of the sun covered by the moon. It would be a shame to miss out on one of the grandest displays of nature when it is occurring just 6 hours away. • What does it feel like to witness a total solar eclipse? I’ll try to describe that next week. A map of the path of totality which includes many of the cities mentioned in this article can be found below.

1283 MARCH 21, 2021: Remembering Eclipse Day: The group of eclipse chasers who Pete Detterline and I organized were invited by Guernsey State Part in SE Wyoming to observe the July 21, 2017 total solar eclipse. We arrived one week earlier, just before a tumultuous storm broke; then on each subsequent night, the weather was clear. However, on the eve of eclipse day, conditions soured. It had been mostly cloudy at sunset with a few drops of rain, and our evening star party with about 100 park guests had been marred by a hazy, partly cloudy sky. Very little could go wrong at this moment except for clouds; the time to move to a new observing location had passed. • I remember crawling into my sleeping bag around midnight and scrunching deep into its down feathers for warmth, but I already knew that even a catnap would elude me. At about 2:00 a.m. I took my first peek at the sky and saw clouds and stars. Conditions were better at three, and by four, the sky was clear with a breeze. At that point I knew we would be successful. Around 5:00 a.m., several members of our group departed northbound to Glendo State Park, WY to eke out nine more seconds of totality on the centerline. By six, the aroma of a wonderful bacon and egg breakfast was in the air, but it was the caffeine from two double-pressed cups of coffee that resurrected me. Written in the present tense is the account of how I remember the eclipse. • By 10 a.m. everything is set. I have been rehearsing this day for a year. I start my time-lapse camera about 15 minutes before first contact. The eclipse begins promptly at 10:24 a.m. with that first tiny bite of sunlight gone. There is no stopping the moon now or ever. Friends in a steady stream visit me to look at the filtered sun on my camera screen. The gusty wind occasionally shakes the telescope. The notch in the sun’s image grows larger. I am already a minute behind with my third sequence, but for some reason that is becoming less important than it was an hour ago. • Sixty percent of the sun has now vanished, causing the surrounding landscape to look eerie—dusky. Shadows have less strength, and my surroundings are beginning to grey; the sky is purplish, not as vibrant. Minute by minute, shadows grow less distinct. The wind has died; the air is cooling. A jacket is now needed. • Five minutes before totality, the sky has become darker in the direction of 10,000-foot Laramie Peak in advance of the onrushing shadow. A minute later, the ground begins to pulsate-vibrate as elusive shadow bands pass over us, created by the narrowing solar crescent. At 60 seconds before darkness, it becomes possible to perceive that the light is continuously fading as if a giant celestial rheostat is being slowly turned downward. The sky is now a deep grey blue. I loosen the screws of my solar filter and whisk it away while looking at the sun to catch the ingress diamond ring, but I miss it with my camera. There is simply not enough time. • The park explodes from all directions with the primordial cries of thousands of unseen voices, including those from our own group. The shadow has arrived. Surprisingly, the camera image looks razor sharp. I take a chance and do not refocus, adding at least 30 seconds to my observing time. The next 90 seconds are spent carefully putting into practice the lessons of eight previous eclipses, but my hands are still shaking a little. I finish my coronal images and set up for the egress diamond ring, then simply look up at the waning moments of totality with the unaided eye. Time is too fleeting for binoculars. As the sky near the sun is growing brighter, two beautiful prominences mark where Sol will reappear. I return to my camera, and luckily release the shutter at just the correct moment to capture Baily’s beads, and then the diamond ring too. One hundred forty-two seconds of darkness have concluded. Everyone celebrates. Five hours later, the gear is packed. With all adrenalin gone, I sleep very peacefully that night—no dreams, just contentment. Our most sincere thanks to Todd Stevenson and Chris Delay of Guernsey State Park. Pictures can be found below.

1284 MARCH 28, 2021: The Many Facets of the Big Dipper: One of my favorite questions that I like to pose to my astronomy students goes like this:

I ask my pupils to slap their tabletops when they believe that I have read the correct answer. The query never fails to create a response with so much confidence and enthusiasm embedded within it that the room resounds with the sound of one unified, echoing whack of hands against wood. So what was the choice that you, the reader, favored? If it was “e,” the Big Dipper, well let me say that you and my students have much in common. The correct response is “b,” Ursa Major. Ursa Major, the Great Bear, is a constellation from which the stars of the Big Dipper are included. • The Big Dipper had its origins with the pre-Civil War star pattern known as the Drinking Gourd. Its seven stars are an asterism, a pattern which could be as famous as a constellation, but has not been officially recognized by professional astronomers. In December 1927, when the International Astronomical Union, the world congress of astronomers, assembled in New Haven, Connecticut, one of their goals was to divide the northern heavens mathematically into constellations with fixed boundaries. I doubt that this august body even considered the Big Dipper as a candidate because the Dipper was viewed so differently by so many nationalities and cultures. • My wife and I were in London many years ago, walking somewhere near the Tower, when I spied a hanging placard advertising a pub with a painted Dipper on it. The establishment was called The Plough. There was no question we were going to have lunch there. Upon our entering, we saw the walls, tables, and floors resplendent with the seven stars of the Big Dipper. However, if I would have spoken to someone in the United Kingdom or Ireland about the Big Dipper, it would have probably been a meaningless conversation unless the person was well acquainted with the heavens. It is the Plough that the Brits and the Irish see in the sky. • Keep in mind, that this is an old-fashioned plow drawn by horses with the bowl of the Dipper substituting for the “moldboard” and “share” which cut the furrows in the field. Currently, if you look at the Plough after dark, it is standing handle down, plow up. However, if you were a farmer in Britain presently getting up at 5:00 a.m., the luminaries of the Plough during the night would have pivoted around the North Star and would be positioned handle up, plow down, a perfect reminder of the day’s errands to be completed. One of my Saudi students commented that in his part of the country, the Dipper represented a sail on a mast rising over the desert, the way it can be seen currently right after dark. A photo is here. The Saudis also see it as a coffin. The Danish call the Big Dipper, Charles’ Wagon; the Germans and Hungarians denote it as the cart, wagon, or wheelbarrow. It is a salmon net in Finland, while the Dutch call it the steel pan or saucepan. The Chinese, Japanese, and Koreans refer to it as the ladle much as Americans do. It is easy to understand why the International Astronomical Union chose to defer to the Greco-Roman and indigenous peoples of North America who almost universally called those same seven stars, plus a about a dozen more, Ursa Major or the Great Bear.

March Star Map]

[March Moon Phase Calendar]