StarWatch for the greater Lehigh Valley
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AUGUST  2019

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

Print Large Sky Charts For 10 p.m. EDT:   NORTH | EAST | SOUTH | WEST | ZENITH

[Moon Phases]

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1198    AUGUST 4, 2019:   Perseid Meteors on the Fly this Week
Last year, my friend Peter Detterline and I volunteered at Guernsey State Park, located in southeastern Wyoming to host a long weekend of viewing the Perseid meteor shower, the best annual shooting star event that combines high meteor rates with temperate observing conditions. We spent four all-nighters entertaining park visitors, stargazing, and meteor watching. By day we gave presentations about how to best observe the Perseids. It was a wonderful experience, but I can tell you that by the fourth nightfall, I was pretty much spent, including developing a sore throat from the dry Wyoming air. That evening, sky conditions were hazy from California wildfires, and then it became mostly cloudy. I decided that because we were leaving for home the following day, it would be prudent to pack up my telescope and camera gear to get a jump on the morning’s activities. It took a little over an hour to wrap carefully and stow my equipment into the numerous cases which I had brought. When I emerged from my yurt a little after midnight, the haze was gone and so were the clouds. The sky was pristine. Our lawn chairs, sleeping bags, and comfy pillows were still beckoning us to join them, but I resisted. Then a bright Perseid scorched the heavens, leaving a short-lived luminescent trail of ionized atmosphere behind it. And then there was another, and yet another. In 10 minutes, I observed 10 Perseids, about as good as it gets for this annual event. So back to the chairs and bags we went, all pumped up by a new adrenalin rush. We each saw an additional 100 meteors before twilight interfered about four hours later. As a kid interested in astronomy, but without a lot of available cash on hand, the Perseids represented my introduction into observational astronomy and for over 50 years, they have provided some of the fondest memories of why I enjoy this science so much. Created by the particulate tail debris discarded from the numerous passages around the sun of Comet 109P/Swift-Tuttle, Perseids swarm into Earth’s atmosphere (mesosphere) at 37 miles per second. They are swift, sometimes leaving a train of ionized gasses behind their fiery glow as electrons reunite with atoms and molecules of tenuous air. The Perseids are active right now, but they peak on the evening and morning of August 12-13. Unfortunately, bright moonlight will play a prominent factor in reducing counts on the maximum evening and morning, but you can catch some of these falling stars this week under darker skies. On Friday morning the moon sets at 12:30 a.m. providing at least four hours of optimum skies for observing; however, on the 13th, moonset does not occur until just after 4 a.m., leaving only a half hour of prime viewing time. Set up your lawn chair with sleeping bag, and pillow facing towards the NE. View the area of sky nearest to the zenith, the highest and darkest part of the heavens. As you begin to catch meteors now and then, you’ll notice that a large percentage of them will appear to be diverging from a vanishing point in the NE. Those will be Perseids. A map and all-night composite image showing the radiant (diverging point of the Perseids) can be found at https://astronomy.org/StarWatch/August/index-8-19.html. Additional information about the Perseids is available at https://astronomy.org/StarWatch/August/index-8-18.html when in 2018, this best-of-the-summer meteor shower was last seen under a new moon. Here’s to a successful Perseid week!

[Perseid Meteor Shower Radiant]
The Perseid Meteor Shower radiant in map form is compared to the activity recorded on an all-night composite image of the same event on August 13-14, 2016 from Flathead Lake, Montana. The visual impression of the Perseid meteors was much brighter than the camera recorded. Photography and map by Gary A. Becker...
[Image of 2016 Perseid Meteor Shower Radiant]
 

1199    AUGUST 11, 2019:   Big Horn Medicine Wheel
I have always been fascinated by archaeoastronomy, the interplay of archaeology and astronomy, that tries to interpret how ancient cultures used the sky for their practical benefits. In my lessons I focus on the Ancestral Puebloans who were responsible for the Chacoan Phenomenon in northwestern New Mexico, starting about 1200 years ago, and the building and use of Stonehenge about 90 miles to the west of London which now is known to predate the construction of the Great Pyramid by over 500 years. Another American treasure is the great Medicine Wheel in the Big Horn mountains of north central Wyoming between the towns of Lovell and Sheridan. When I first saw it in 1979, the 80-foot limestone rock circle, with its central raised hub, radiating 28 spokes and six cairns along its circumference, was encased by an ugly metal fence capped with barbed wire. That has all changed. When I revisited the site last month with friends, the old fencing was gone, replaced with a low, four-foot high circle of vertical posts with three rungs of white nylon rope running between them. Standing behind this aesthetic boundary, the entire wheel was accessible to the eye unobstructed, blending naturally with the open windswept mountaintop and the brilliant blue turquoise sky which dominated the area overhead. The “why” behind the Big Horn Medicine Wheel’s construction is uncertain—legends abound, but archaeoastronomers feel that its connection with the sky is very compelling. Using two of the five cairns and the central hub, the wheel points accurately to the summer solstice sunrise and sunset positions, the longest day of the year and the point in the solar cycle where the “sun stills” (solstice) its upward motion before beginning its slow retreat into its cold, winter “house.” Observing from the central hub, summer solstice sunset is opposite to winter solstice sunrise, and summer solstice sunrise is 180 degrees away from winter solstice sunset. In theory on a flat surface, all would be perfect, but to my knowledge the winter solstice alignments have never been tested because by December, the 9,642-foot altitude of the Medicine Wheel is covered in deep snow. It was probably only used during the warmer months. In fact when I was there on July 3, the site was recovering from a major snowstorm just several weeks earlier that had dropped something like five feet of wind-tossed powder on the higher elevations. Another cairn alignment also supported the heliacal rising of Aldebaran in Taurus the Bull. A heliacal rising of an object means that it was first seen just before the brightening light of a new day washed it from visibility. This was followed 28 days later by summer solstice and 28 days later by another alignment pair of cairns which pointed to the heliacal rising of Rigel in Orion the Hunter, followed by another pair of cairns about 28 days later which reinforced the heliacal rising of Sirius, the brightest star of the nighttime sky. Aldebaran may have worked as a predictive marker, the ribs of the wheel acting as a counting device to predict the summer solstice, while the rising of Sirius, 56 days after the high sun in mid-August, may have been the time to leave the Medicine Wheel because of the encroaching chill of autumn and winter. Since the rising and setting positions of the stars change because of the 26,000-year wobble of the Earth’s axis known as precession, it is possible to date when these stellar alignments worked, and therefore, when the Medicine Wheel was in use—1400 AD to 1700 AD. This agrees with the archeological record detailing the time of the construction of the site (John A. Eddy). The great conundrum of archaeoastronomy is that as compelling as these facts may sound, we can’t interview the person or individuals who masterminded and constructed sites like the Big Horn Medicine Wheel to glean their specific intentions, but it appears that the sky played a significant role in the lives of these Native Americans. In archaeoastronomy, the stones pose tantalizing mysteries with multiple interpretations. Photos are online at https://astronomy.org/StarWatch/August/index-8-19.html, StarWatch 1199.

[Medicine Wheel Alignments Diagram]
The Medicine Wheel located in the Big Horn mountains near Sheridan, Wyoming may have been constructed to align with the rising and setting sun at summer solstice and the heliacal rising of three bright stars. See the photographs for credit.
[Medicine Wheel Alignments Diagram Photo]

[Medicine Wheel without the Drawn Alignments]
 

1200    AUGUST 18, 2019:   Bright Star in the South
“Hey, what’s that bright star in the south, just below the moon?” queried volunteer Alexander Pavkovic, a senior at Nazareth High School with an interest in astronomy. Alex has been helping me prepare and set up the telescopes on the Sky Deck for the fall term. “You’ve got the hand controller and know how to use it. Find it for yourself,” I retorted. The telescope made a short slew; Alex leaned toward the eyepiece, focused, and I heard a softly spoken, “Wow, is that Jupiter and the smaller stars in a straight line its moons?” “Yup,” I said, happy that a new discovery had been made. Seeing the real deal, the actual photons of light that have traveled nearly a half a billion miles, gathered by the telescope, magnified by the eyepiece to produce the image that is being viewed, has always been a rush for me. It’s like a live concert. Yes, beautiful colored pictures of Jupiter and its Red Spot abound, but it just isn’t as “cool” as looking through the eyepiece yourself. A day or so later, we were again on the Sky Deck, and this time Alex knew full well what he was seeing in the south. Yet this time when we slewed the scope over to Jove, there was this dark roundish blob in Jupiter’s southern hemisphere, the Great Red Spot, a storm of sorts with high winds, but really a high-pressure system that has been churning for over 350 years. It has been decreasing in size during the past few decades, and lately, it seems to have become a little wispy with parts of it shearing off, leading some experts to predict its demise was at hand. However within the last month, the spot has become redder, making it a slam-dunk observation when Jupiter’s rotation brings it around to our side. When we look at Jupiter, what we are really observing is its turbulent, upper atmosphere which is segmented into belts and zones by the planet’s rapid rotation (spin). Belts are darker, where the atmosphere is descending and warming, while the brighter, cooling zones are ascending gases containing small amounts of ammonia, hydrogen sulfide, methane, and water vapor in Jupiter’s mainly molecular hydrogen and helium atmosphere. The ammonia and water vapor freeze as the air rises giving the zones its whitish appearance, while in the descending, warming belts, these same gases liquify—darkening, an indication of possible chemical reactions that are occurring but which are not well understood. The atmosphere thickens with depth, transitioning into a liquid about 600 miles below the cloud tops due to its own pressure, creating a hot ocean of mainly molecular hydrogen. Again, pressure wins over increasing temperatures to split the molecular bonds and create a region of metallic, atomic hydrogen about 10,000 miles below the observable clouds where astronomers believe Jupiter’s huge magnetic field is generated. Below that is a core between 12-45 times the mass of the Earth with an unknown composition. Even though most individuals do not have the means of viewing Jupiter through a larger telescope, it is still enjoyable to identify that the bright “star” in the south right after nightfall as the one and only, biggest—89,000 mile in diameter—and most massive planet in the solar system. Keep looking up, and thanks Alex, for all of your help!
 

1201    AUGUST 25, 2019:   Serendipity
My wife, Susan, believes that there are no coincidences, that everything happens for a reason. Among scores of chance experiences that I have encountered during my life, including how we met, I might just be coming over to her side. I flew to Denver this past summer to travel with friends, Adam R. Jones and Lee Recca. One of our stops was at a guest ranch owned by Tom Higginson, about four miles south of Moab, Utah on the Colorado. Unless you travelled by water from Moab, getting to Tom’s place involved traversing a dirt road that even my Jeep Sahara would have found daunting at spots. It was there that I met Kobae, a 19-year old African tortoise who weighed 150 pounds. I knew next to nothing about tortoises, but discovered that they are quite different from turtles which I had as pets when I was in grade school. As an example, tortoises will drown in water—they can’t swim; they are vegetarians, and if flipped over, they will die of organ failure because they cannot right themselves. Kobae exited his wooden hut as predicted by Tom after the heat of the day had waned and made his way over to the large porch surrounding the ranch house where a banquet of fresh romaine lettuce, red and green peppers, and carrots awaited his consumption. Because there was another guest sitting on the porch steps, Kobae headed directly for the food and ran into an immediate problem. He couldn’t lift himself onto the porch without the intermediary step. After about five minutes he gave up, leaving out a sigh, s l o w l y backed away, and trudged off through the scrub vegetation in a different direction. “You dumb (fill in the blank), I thought,” but as I watched him, I noticed he was moving in a large sweeping arc which would bring him to the end of the long porch where there was a dirt ramp, no steps, and easy access to the food. From that moment on, I had a new appreciation for tortoises and keenly observed Kobae’s habits, which included taking perhaps a hundred photos of him during the next two days. Several are posted online with this article at https://astronomy.org/StarWatch/August/index-8-19.html#8-18-19. Tom also told me that he took Kobae on walks, some as long as seven miles—man and tortoise disappearing into the parched, mesa-pinnacle-sprinkled landscape of arid, red rock, eastern Utah—a laidback lifestyle so different from the hectic East Coast circus with which most of us are familiar. Fast forward to last week when I was exiting my driveway to visit my favorite toy store, telescope and astronomy gear central, Skies Unlimited, in Pottstown, PA. I immediately noticed cars pulling over to the side of the road, and when I passed them, I realized why. There was this large—18-inch shelled “turtle” walking defiantly across my neighbor’s yard. With two dogs barking at this spectacle, I yelled at the homeowner, Kim, to get them inside because it could have been a snapper. I had experiences with them too. However, when I approached it, I immediately realized that it was an African tortoise, a miniature Kobae, harmless, on a mission to escape the dogs. One of the individuals who had stopped, helped me to get him into a large running cage that my wife and I use to let our pet rabbits get some exercise, and Sue gave it a smorgasbord of carrots and apples. By the time I returned with more “stuff” for my astronomy classes at Moravian, my wife had contacted the police, and they had reunited it with the family down the block who had reported it lost. Mini Kobae had been on the loose for two days. What were the chances of meeting up with and recognizing an African tortoise in Coopersburg, PA? My acquaintance with Kobae on the Colorado must have been serendipity.

[Kobae]
Tom Higginson, who owns a guest ranch on the Colorado River, four miles south of Moab, Utah, feeds Kobae an African tortoise near sundown on the evening of June 29. During the winter months, Kobae resides in the San Diego zoo. Friends and I stayed there for two evenings, lodging in a primitive hogan on a hillside overlooking the ranch house and the river. All photography by Gary A. Becker...

[Kobae]

[Kobae]

[Kobae]
 

[August Star Map]

[August Moon Phase Calendar]
 

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