StarWatch: Moravian University Astronomy

MAY 2023

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

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lunar phases

1394 MAY 7, 2023: Observing from Perth, Western Australia: Written on April 18: Perth, a city of about 2.1 million residents, was my final 28-hour flight destination before boarding the P&O Explorer which would take my good friend, Peter Detterline, and me to a rendezvous point with the moon's shadow on April 20. We had a day-and-a-half in Perth to explore an ultra-modern, friendly, incredibly clean city that would make any American locale of its size envious. Perth is a magnificent example of what a metropolis can achieve if its administrators are working for the good of its citizenry. * That is not my reason for writing this piece. Pete wanted to walk down to Langley Park, located along the Swan River about three blocks from our hotel, to look at the stars about 10 p.m. on our second evening in the city. Keep in mind that the park is completely surrounded by Perth, which horseshoes around this rectangular oasis of green and then continues across the Swan River which in this area looks more like a small ocean bay. You could smell the brackish water mixing with the fresh waters of the Swan from the park. I was hesitant, not because I was afraid that there might be unsavory characters roaming the area—we saw no poverty anywhere that we walked—but because of my viewing experiences on the Sky Deck at Moravian University in center city Bethlehem. * On a transparent night, I might be able to witness 50 stars at most. You can double that number for my students because of their younger, more sensitive eyes. * We walked down a steep gradient from our hotel, the Pan Pacific, with our binoculars and out onto the openness of Langley Park with no more than two blocks separating us from the center city skyscrapers. It was a Central Park-type location, but without the trees to obscure the night sky. * WOW, there were hundreds of stars visible. Of course, anything recognizable from the Northern Hemisphere was upside down in the early evening sky, but it was exciting to see so many stars from an urban setting. America could learn a lesson to better control its wasteful, sky-directed light pollution. * In the Southern Hemisphere, looking north means that the sky appears to move in a clockwise direction as the Earth rotates, so the rising and setting constellations appear to the left and right, respectively. For someone who has been into astronomy since third grade and has a little bit of dyslexia, it felt like I was a novice observer again, a good reminder that will help me to remain empathetic as my students struggle to learn the brighter stars and operate the instrumentation housed on Moravian's Sky Deck. * However, the real show was high in the east where the unmistakable Southern Cross twinkled distinctly against the slate grey sky. Below was Beta and Alpha Centauri. The Alpha system of three luminaries represents the closest stars to our sun. Between them and across a large swath of sky which leads to Sirius, the brightest luminary of the heavens, was Canopus, the second brightest star of the night. The Alpha Centauri system comes in third. Orion the Hunter was plowing head first into the city as was Canis Major. See my smartphone photos here. * Still, there was much more to witness with binoculars, such as the largest globular cluster in the heavens, Omega Centauri, similar to, or perhaps a miniature, captured elliptical galaxy in itself, with a population of one million stars; Eta Carina, the most active region of star formation in the Milky Way Galaxy; and the Large Magellanic Cloud, a small, shredded spiral galaxy that now looks more like an irregular galaxy in a decaying orbit around the Milky Way. It was a wonderful start to the forthcoming eclipse and our dark sky adventures, but from a large, clean, safe metropolitan center. Ad Astra!

1395

MAY 14, 2023: Success in Viewing the Australian Solar Eclipse

For those individuals who have never had the opportunity of viewing a total solar eclipse, when the moon passes centrally in front of the sun, and day rapidly changes into the near darkness of night, it is something that you want to put on your bucket list. Canada, Hawaii, Africa, and many central eclipses across the continental US, and now Australia have been my stomping grounds for eclipse chasing. * Why travel halfway around the world to see an eclipse? Solar eclipses can only occur when the moon is new and that means for a week after new, Luna is not bright enough to hinder observations and imaging of the night sky. My friend, Peter Detterline and I had a house rented near Franklin River, Western Australia for six nights to accomplish those goals. Although I had been to Australia 23 years earlier to photograph the stars of the Southern Hemisphere from Oz's Siding Spring National Observatory, the digital revolution had made those images obsolete. I also had never seen the central bulge of our Milky Way Galaxy on my first trip because I had been to Australia during late summer when the galactic hub was just rising as morning twilight interfered. * So here I was on the deck of the P&O Pacific Explorer ready to observe an eclipse that was different from any other that I had experienced. It was a hybrid, starting and ending as a ringed (annular) eclipse with the moon's main shadow, the umbra, too distant from Earth's surface to create totality. As the moon's shadow raced across the Indian Ocean, the Earth bulged towards the moon, allowing a narrow oval of darkness to continue sprinting across the sea to rendezvous with us on the eastern waters of Australia's sunny North West Coast. * Because the shadow was so narrow, only 40 miles along its minor axis, this totality was going to be extremely short, 60 seconds of darkness, before the light of the sun would again return. * The partial aspects of solar eclipses are pretty standard. They begin with the faster moving moon overtaking the slower moving solar disk. This takes place during an approximately 80-minute interval and is not excessively exciting except for the anticipation of totality that will be occurring imminently. Somewhere between 10 to 15 minutes before darkness, the sun's light noticeably begins to fade. During this interval, the sky becomes a more saturated blue, sometimes even taking on a grey or purplish hue. Shadows weaken, but become more distinct as the solar crescent narrows and acts more like a point source of illumination rather than a broad disk. In the direction of the oncoming shadow, the sky can darken like an advancing thunderstorm, but this was less evident because of the narrowness of the umbra. About two minutes before totality, the light can start to pulsate or ripple from the contracting slit of sunlight passing through different temperature layers of Earth's atmosphere, a phenomenon known as shadow banding, but again I did not witness this elusive phenomenon with this hybrid eclipse. * During the last minute before darkness, it seems as if someone is turning down a giant dimmer switch as the sun's light noticeably fades moment by moment. The moon appears like a diamond ring created by the outer atmosphere of the sun, the corona, now visible against the last jewel of sunlight to disappear. * Prominences created by fluorescing hydrogen gas arcing from the sun's limb were noticeably visible, as well as the middle layer of the sun's atmosphere, the 2000-mile-deep, magenta chromosphere. Because the moon and the sun were so close to being the same apparent size in the heavens, the diamond ring was broad and long-lived. * As the brief night of totality blanketed the Pacific Explorer, the ecstatic cheers, hoots, and screams of more than 2000 passengers and crew added a surreal and primal quality to the experience. I know now to expect it, but I'm still surprised and inspired by its intensity every time I experience a total solar eclipse with a large group of novice observers. The awe and majesty of this event just seems to be a part of our human DNA, as everyone is surprised by the sudden darkness. Pictures cannot convey the rush of excitement or the sensations that pulsate through your body during the totality experience, but here are a few images that I took which may capture some of the beauty and encourage you to want to view one of these inspiring events for yourself. More stories about my adventures in Australia next week. More about eclipses next week. Ad Astra!

The ingress partial phases of a solar eclipse are not that exciting except for the anticipation of totality and the 10 to 20 minutes prior to darkness. Gary A. Becker images from April 20, 2023 aboard the P&O Pacific Explorer...

The ingress diamond ring begins to appear about 20 seconds before totality and can be viewed with the unaided eye if the light does not overwhelm the observer's vision. Still, caution must be exercised because the sun is a dangerous star to observe even in near totality situations. The safest and only advice that someone can give is to wait for the sun to be completely covered by the moon so that none of its dangerous, light-emitting photosphere is visible. Gary A. Becker images moments before totality commenced on April 20, 2023...

Very short exposures taken immediately after totality begins will reveal prominences and the sun's middle layer of atmosphere, the chromosphere which appears pink or magenta in color. Gary A. Becker image...

Longer exposures allow the sun's outer atmosphere, the corona, to be revealed in significant detail. Gary A. Becker image...

Because the shadow cone of this eclipse was only about 40 miles wide along its minor axis, enough light was able to leak (to be scattered) into the shadow cone to produce a blue sky in this longest exposure. It did, however, increase the length of the coronal streamers extending away from the sun. To the unaided eye the sky appeared black around the sun. Gary A. Becker image...

The egress diamond ring is the easier of the two diamonds to capture because the sky begins to brighten as a forewarning to the event. Gary A. Becker images...

Now the moon races ahead of the sun in reverse order, creating the egress partial phases. The ingress and egress partial eclipses last about 75 minutes each. Almost no one follows a solar eclipse to the very end, fourth contact, but I like to show the complete story when conditions permit. Gary A. Becker images...

1396 MAY 21, 2023: So You Want to See a Solar Eclipse?: I have told my students for over 50 years that if they do not see a total solar or annular eclipse in their lifetimes that I will personally come back and haunt them until they comply. They laugh now, but "You just wait," I tell them. It is a must-see experience which causes some to become manic and others to cry. Some even say it is life-changing. * The next two eclipse seasons feature central events that will be visible in the United States, one occurring on the 14th of October of this year where the center of the moon passes in front of the center of the sun, but the moon is too far away from Sol to be a total eclipse. A ring of fire surrounding the sun will be the result, an annular eclipse, dangerous to observe with the unaided eye unless proper filters are employed, but nevertheless still a spectacular event. The annular event will be visible in Oregon, the southwestern US, and Texas. Locally, a partial solar eclipse will be seen. * Nearly six months later on April 8, 2024, a total solar eclipse moves northward through central Mexico, across Texas, the Midwest, straddling the eastern side of the St. Lawrence River, and up through central Maine. It will produce over four minutes of totality in the Lone Star State and about one minute less as the moon's shadow transits through western and central Maine. That is more time in the darkness of Luna than the combined duration of the last two total eclipses that I have witnessed. Cleveland, Erie, Buffalo, and Rochester are all positioned within the central path of darkness for this afternoon event, an experience that will leave most first time viewers breathless and wanting to see another. These should be your next two eclipse goals for viewing the cosmic dance between the sun and the moon. * However, what about eclipses that target places outside of the US? In 2026 it's Spain; 2027, Egypt; and 2028, it is back to Australia. There are numerous agencies that can be enlisted to ensure that you and the moon's shadow will make a precise rendezvous that will produce an unforgettable experience. The weather is the one consideration that none of these enterprises can guarantee, but these travel groups try to select locations that will be weather favorable. * Since your probability of seeing a total solar eclipse in the location where you live occurs about once every 350 years, odds are that you will be dead and buried long before one happens over your neighborhood. In fact, even if life expectancy were increased to 1000 years, there are still places on the Earth where the moon's central shadow would not touch. So expect to become a nomad if you desire to see an eclipse in your lifetime. * Both Pete Detterline and I have enlisted the help of Insight Cruises and the staff of Sky and Telescope magazine that work cooperatively to produce astronomical tours, many of them involving eclipse chasing. They enlist the help of world class umbraphiles like Mr. Eclipse, Fred Espenak, who has literally written some of the definitive books on the subject. * An example of their latest enterprise was our adventure on the 1800 passenger P&O Pacific Explorer to view the April 20 total solar eclipse from the waters off the North West Coast of Australia, near the small town of Exmouth. About 140 people participated in our group, but all of the passengers had signed up with the specific intention of viewing the event. * Do you want to travel down the Nile from Aswan to Cairo to see the summer 2027, six minute, 20 second duration eclipse from Luxor, Egypt? Yes, it will be hot, but there is no eclipse with a longer totality left this century. The journey according to Insight Cruises which includes many other options is about half booked at the present moment. In addition, Insight cruises and other agencies are also making arrangements for southern Spain, Iceland, and Greenland for the 2026 total solar eclipse, and a return to the northern part of Western Australia or Sydney for another total solar eclipse in 2028. Then there is Iceland, Alaska, or Norway to view and photograph the aurora, which should also be placed on your bucket list. * If you enjoy traveling, don't overlook the possibility of chasing down at least one total solar eclipse during your lifetime or participating in other astronomical adventures. You'll get to meet some very fascinating people in an atmosphere of like minds and spirits, with lots of comradery, and plenty of stories to tell when you return home. Ad Astra!

1397 MAY 28, 2023: The World Turned Upside Down: Written on April 24/25, 2023 in the moment: When General Cornwallis surrendered to George Washington at the Battle of Yorktown in the early fall of 1781, a ballad entitled, "The World Turned Upside Down," was purportedly played by the British military band as they marched to their surrender. Those are my sentiments as I capitulate my Northern Hemisphere biases to observing the sky in the "Land Down Under." It also reminds me of the questions that I got from many elementary students with respect to how it was possible to stand upright in Australia. Didn't they get an awful number of headaches with all of that blood rushing to their heads? "Gravity, my friends, it always points to the center of the Earth. They feel no different than we do," would be an abbreviated retort. * However, it does feel strange to think that my wife's feet are pointing towards me and mine towards hers because we are literally a half a world apart, me in Western Australia at 34 degrees south latitude and 12 hours of time difference, and she in the Lehigh Valley. I have also had a slight headache for two days, so maybe those third graders had it correct after all. I think that my nuisance, however, has been from the excitement of watching the southern sky and a lack of sleep. * As I write this, my friend Peter Detterline and I are several miles from the small town of Franklin River in the south-central region of Western Australia. The roads just simply stop about 50-100 kilometers to the east of here. * Today, the puffy cumulus clouds containing some sprinkles are coming off the Indian Ocean. The cleansing of the air as it has passed over thousands of miles of water has produced one of the bluest skies that I can remember, but there is rain in the forecast, so we are hoping for a few good hours of imaging tonight before the bad weather moves in. * From my first visit to Australia in 2000, I discovered that the Southern Hemisphere has it all over the North. In the early evening, mid-autumn sky that I am observing currently, spring for us in the north, the Milky Way arches across the heavens, increasing in splendor just at the mid-latitude, Northern Hemispheric horizon. However, in the S. Hemisphere it continues past the False Cross towards the Southern Cross which to its west hosts an amazing assortment of deep sky splendors which are all visible to the unaided eye, such as the Southern Pleiades star cluster; Eta Carinae, the most active region of stellar generation in the galaxy, and the Running Chicken Nebula, which really doesn't look like it's running or a chicken. Next to the Southern Cross is the Coal Sack, a dark cloud of obscuring dust that the Aboriginals named the Emu (bird) and the Jewel Box, a tiny open cluster of stars born in concert next to the star Mimosa of the S. Cross. To the east of the Cross are Alpha and Beta Centauri. The Alpha system, composed of three luminaries, are the closest stars to the sun. Alpha, including its brighter close companion which to the unaided eye appears as one star, represents the third brightest star in the heavens. I didn't mention that Canopus, the second brightest nighttime luminary, and Sirius, the brightest nighttime star, are also visible at the same time in the early evening sky. * However in my estimation, the flagship of the southern sky is the bulge of the Milky Way Galaxy which in the autumn becomes prominent after midnight. It is impossible for me to imagine how early observers of the southern heavens believed that the solar system was at the center of the universe when this huge bulge straddles the southern sky's zenith. Our thoughts were geocentric for far too long or perhaps a better word, egocentric. Pictures are below. Ad Astra!