StarWatch: Moravian University Astronomy

StarWatch for the greater Lehigh Valley

APRIL 2023

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1389 APRIL 2, 2023: The Cow Killer: I was at a rock and mineral show in Cortez, Colorado in 2001, and came across a number of Valera meteorite specimens. I recognized the name from reading several articles and seeing images of this specific hammer stone that had killed a cow on a cattle ranch in Valera, a city in Trujillo State, in northwestern Venezuela on October 15, 1972. After nearly 30 years this stone had finally made it to market, and some of it was being sold by John Schooler, a reputable meteorite dealer from Kansas City, Missouri. Unfortunately, Schooler Meteorites closed its doors to sales in 2018 after the passing of John's wife. * The fall was documented in a signed affidavit in 2001 by Juan Dionicio Delgado, a guest of Dr. Argimiro Gonzalez, a physician who was the owner of the ranch. Years later, Delgado believed that the incident was important enough to be officially recorded. A translation of the majority of his affidavit from Spanish is presented here. * I, Juan Dionicio Delgado, Venezuelan, declare that at the end of 1972, I was visiting the farm 'El Tinajero,' owned by Argimiro Gonzalez, deceased, which was located in the limits of the states of Barinas and Trujillo. It was past midnight when we were talking, and there was a strange noise. When we went out to investigate, due to the dark of night, we saw nothing. But the next morning a worker came to say that there was a cow killed in strange circumstances. When we went to investigate, we found that the cow had been killed by a stone that presumably had fallen from the sky the night before, causing the noise that we had not been able to explain. The stone which had been broken into several pieces, was kept by Dr. Gonzalez, while the cow was eaten in the following days. I relate this account in Barinas, on January, 11, 2001. * The meteorite had broken into three pieces with masses of 38 kilograms (83.6 pounds), 8 kg (17.6 pounds), and 4 kg (8.8 pounds). The fireball that had accompanied the entrance of the meteoroid into the atmosphere as well as the sonic boom that it created were both witnessed by Delgado and Gonzalez, but the document is not specific enough as to whether the noise heard was due to the impact and death of the animal or the sonic boom. The next day, Argimiro Gonzalez went outside to find the neck and clavicle of one of his cows pulverized, with a strange rock sitting next to the carcass. A photograph was taken of the main mass of the Valera meteorite, complete with grazing cattle in the background. Shortly after the meteorite was recovered, Argimiro Gonzalez placed the main mass on a fencepost near his ranch house. Another fragment was purportedly used as a doorstop by Gonzalez. See photos here. The main mass remained outside for 19 years before being discovered by an astronomer, Dr. Ignacio Ferrin who approached the heirs of Dr. Gonzalez, and then purchased the meteorite after verifying the story with several witnesses. Ferrin presumably sold parts of the meteorite to museums and to collectors. * At Schooler's booth, one of the pieces was a broken, elongated, triangular, 54.5-gram section from the main mass with fusion crust on one side, a cut and polished panel on the second surface, and a rough face from breakage on the third side. The fusion crust meant that this Valera specimen had been on the exterior of the meteorite when it entered the Earth's atmosphere, its dark surface being the ablated (melted) skin created by heating as it passed through the air. I purchased it. * Ironically, a day after returning home from this western trip where I was volunteering as a Night Sky Interpreter at Chaco Culture National Historical Park in New Mexico, this Valera slice was used in a television interview with Channel 69 News after the Salladasburg, PA meteorite detonation of July 23, 2001. Thousands of people witnessed an unexpected fireball which appeared over the US East Coast at 6:15 p.m. local time. No pieces of that event were ever identified. Ad Astra!

APRIL 9, 2023: Rarest of Solar Eclipses to Take Place on April 20

As an eclipse enthusiast who enjoys bathing in the shadow of the moon, I need to say something about the hybrid solar eclipse that will sweep across the Indian Ocean on April 20, touching only three areas of land, the North West Cape of Australia about 800 miles northward of Perth, then skimming along the northeastern edge of the island of Timor-Leste (Indonesia) and the western edge of the island of New Guinea which is also part of Indonesia. Indeed, it touches so little land that the best way to see it will be by ship which can maneuver its passengers into clear areas along the track of totality if inclement weather threatens. * A year ago, hotel prices in Exmouth, a popular tourist destination for Australians with abundant sun, beaches, and flies, positioned on the northern fringes of the path of totality, were selling for $1000 per night. I had to laugh because no one sleeps soundly on the eve of a total solar eclipse and certainly not at those prices. The anticipation of what will be perceived on E-day is absolutely electrifying. * A hybrid eclipse is also special. It is a type of solar eclipse where along the center line an observer will witness the center of the moon passing directly in front of the center of the sun. It is the location of longest duration. However for this eclipse, as the moon's main shadow, the umbra, begins its sweep across the Earth, it will not be quite long enough to touch the Earth's surface. Observers here will witness the entire limb (circumference) of the solar disk broken into the "pearls of Baily" or more commonly called Baily's Beads. This is the result of glittering sunlight shining through the valleys between lunar mountains which are projecting outward from the moon's limb, blocking the sun's light. It is an event that lasts for just a couple of seconds and creates the phenomenon of a beaded sun surrounding the entire lunar disk. I saw a broken annular eclipse from Osceola, North Carolina on May 30, 1984, with one major exception. There was no place along the center line where this eclipse became total, so it really was not a hybrid event. * On April 20 as the moon's umbra sweeps across the Earth, the Earth's curvature will project outward to meet the moon's shadow. At this locality the eclipse will become total and remain total for the majority of its path before returning to becoming a broken annular eclipse near the end of its trek when Sol is approaching sunset low in the west. * Hybrid eclipses account for about four percent of all solar eclipses that can be seen by observers willing to make the effort to travel to them. However, the classic hybrid eclipse begins normally as a ringed (annular) eclipse, has a period of broken annularity along its center line, then becomes total, reversing this order as the moon's main shadow sweeps towards the end of its path and lifts from the Earth's surface. The April 20th eclipse starts as a broken annular, proceeds to total, and then ends again as a broken annular event. That is an even less common form of a hybrid eclipse. * After this solar eclipse, umbraphiles shift their attention to the US where two central solar eclipses will happen within the timespan of less than six months, an annular (ringed) eclipse on October 14, 2023 which focuses on Oregon, Nevada, Utah, New Mexico, and Texas, and a total solar eclipse on April 8, 2024 where the path of totality passes within 300 miles of the Lehigh Valley. In both cases, staying put locally will net viewers a partial solar eclipse, but appropriate filters will be needed to view the event safely. More about these eclipses in the upcoming months. Pictures are below. Ad Astra!

A much younger Gary A. Becker (33 yo) records the broken annular eclipse from Osceola, North Carolina. Image of Becker courtesy of Charles Tackus/Eclipse images, Gary A. Becker...

Sky During Totality, April 20, 2023

1391 APRIL 16, 2023: April Lyrids Spark Beginning of Meteor Season: Mid-April marks the beginning of the meteor season with the Lyrid shower providing the first major activity in nearly three-and-one-half months of meteor scarcity. During the winter, starting in early January after the Quadrantid Meteor Shower and through early spring until the Lyrids, the Earth does not intersect any large amount of organized cometary debris which produce Earth's annual meteor events. * Comet Thatcher (C/1861 G1 Thatcher), a long period interloper that requires 415 years to navigate around the sun, is responsible for the Lyrid display, one of the oldest witnessed annual meteor events in astronomy. Chinese records date the first observation of the Lyrids to 687 BCE. * It is the dust from a comet’s tail intersecting Earth's orbit that triggers an increase in the rate of shooting star activity. The radiant, from where the meteors appear to be diverging, is the undisputed indicator that these shooting star events are related to each other. The larger silicate particles released by the nucleus in a comet’s outgassing processes, as it nears the sun and is warmed by Sol, follow the comet’s orbital path. These particles are moving essentially parallel to each other, so that when they enter the Earth’s atmosphere, they appear to diverge from a point in the sky, similarly to a long stretch of roadway which appears to diverge from a vanishing point far off into the distance. In astronomy this is called the radiant. * Even though it is spring, Lyrids emerge from a location that can be traced back to a part of the summer sky near to the constellation of the Lyra the Harp. When facing east and observing Vega, the radiant is to the right and above this brilliant, blue-white star. Vega was the luminary that the fictional feature film, Contact, made famous because it was from here that the first extraterrestrial message was received by radio astronomers in Socorro, New Mexico. * Don't expect to view many Lyrid meteors early in the evening because the radiant is too close to the horizon. Activity picks up after 11:30 p.m. local time as the radiant increases in altitude. By 1 a.m. Vega is almost mid-sky in the east on the morning of the 22nd when the Lyrid meteors rates are predicted to be at their greatest. * That's because our part of the Earth begins to head directly into the path of Thatcher's debris. In addition as Vega climbs higher into the sky, observers can witness meteors coming from below the radiant as well as from above. * Don't expect the sky to be ablaze with shooting stars, although outbursts sometimes occur, like the one in 1982 which favored the US and produced about 90 Lyrid meteors per hour from a rural locale. Rates are normally about 14-20 meteors per hour from a dark site during the post-midnight hours when the radiant is prominently placed in the sky. * To observe the Lyrids, face eastward inside the cozy comfort of a warm sleeping bag with a soft pillow under your head and gaze straight up at the zenith which is normally the darkest part of the heavens in a suburban or urban location. Lyrids will seem to trace back close to Vega. Just don’t let the stillness and serenity of the morning sky and the verdant fragrance of the spring air put you to sleep. Good observing for the first of a handful of major meteor events which will be occurring in a moonless sky! Scroll down for a map below. Ad Astra!

1392 APRIL 23, 2023: Trekking with the Moon: This Week and Next: There are a lot of interesting objects to spot in the sky during the next two weeks, and once again the waxing moon can help you find them to produce some enjoyable viewing. This was a recent theme of several earlier StarWatch blogs which received a number of positive comments, so I thought I would try it again. * There are eight phase names in the 29.53-day lunar cycle, a one-night phase series that happens every six or seven days: new moon, first quarter, full moon, and last quarter; and four other phases that happen throughout a six-to-seven-day period: waxing crescent, waxing gibbous, waning gibbous, and waning crescent. Waxing means to grow; the sunlight reflecting from the moon is on the right side of Luna as we view it with the unaided eye or through binoculars. The waning moon is decreasing in its reflected sunlight reaching Earth. That mirrored light is always to the left. Gibbous means bulbous, where the terminator, the location on the moon where the sun is rising or setting, curves outward. Crescent means to have horns, like the croissant you may have had for breakfast in the morning. At these times the terminator is concave. When the moon is in a quarter phase, the terminator is straight. The phases of the moon are shown below in their correct order starting and ending with the new moon. Follow Luna this week and the next as she waxes into its full phase.
Sunday, Apr. 23: The thin 16 percent sunlit, waxing crescent moon stands five degrees above the planet Venus tonight. View around 9 p.m. If you have a good western and southwestern horizon, Orion will be bent forward almost ready to set. That bright luminary in the SW is Sirius, the most luminous star in the nighttime sky.
Tuesday, April 25: A plumper, waxing crescent moon is positioned just three degrees to the right of the planet Mars. The Red Planet has dimmed considerably since it nearly grazed the moon on December 7, but it still remains bright enough to be seen easily near the moon with the unaided eye.
Wednesday, Apr. 26: Luna is positioned this evening to the left of the two principal stars of the Gemini Twins. Pollux, slightly brighter and closer, is just under four degrees distant, and Castor is eight degrees from the moon.
Thursday, Apr. 27: The moon is at first quarter at 5:20 p.m. EDT this afternoon. By the time it gets dark, look for a virtually straight terminator, the location where night is changing into day as the moon continues to wax. After tonight the moon turns gibbous.
Friday, Apr. 29: This evening the waxing gibbous moon is located near the Sickle of Leo the Lion. The Reaping Hook looks like a backwards question mark and is an asterism that is not officially recognized as a constellation, but as part of the lion. Binoculars will reveal the fainter stars of the Sickle.
Saturday, April 30: Overnight, Luna has moved 12 degrees to the east and is now just to the left of the two brightest stars of the Lion. Regulus is the brighter star below, while Algieba is above Luna.
Wednesday, May 3: The moon, two days from full, is less than three degrees above and slightly to the left of the blue supergiant, Spica, in the star pattern of Virgo the Virgin. Make Spica's blue hue more vibrant by using binoculars.
Friday, May 5: The moon is in its full phase at 1:36 p.m. EDT. Look for it to rise just after sunset about 8:15 p.m. and illuminate the landscape with its brilliance as darkness descends.
We have followed the moon through nearly half a lunation (phase cycle). Keep looking up and enjoying the heavens! Ad Astra!

1393 APRIL 30, 2023: Calendar Keepers: Virtually all cultures began their calendar making systems by using the moon's phases for farming purposes, even though it was obvious that it was the sun that was responsible for growing crops. There was a good reason for this. The moon was easy to observe. It changed its shape and position in the sky nightly, and perhaps most importantly, it repeated this same sequence of events every 29.53 days. The challenge was keeping the sun and the moon synchronized because the mathematics of most ancient cultures dealt only in whole numbers. With the exception of the Egyptians, there were no symbols for fractions. * If the modern phase period of the moon is divided into the true orbital period of the Earth, the Sidereal Year which contains 365.26 days, then there are 12.37 lunations occurring within a year's time. How were ancient astronomer priests to handle the 0.37 lunation or the extra 10.93 days when only whole numbers were used? Keep in mind that we are looking at a problem faced by keepers of the calendar through the eyes of modern calendric systems and arithmetic which incorporates fractions. * Let's say on the first year that farmers were called to plant on the 13th of May, within the period of the last killing frost for Allentown and Bethlehem, PA (May 11-20), and it was decreed that the next planting would happen 12 full moons later. The following year, planting would happen on May 2, probably still not a problem since that date was still close to the limit of a killing frost. However by the third year, seeds would be planted on April 21, and that would entail a greater risk of crop failure. The year after that would be pure folly, planting on April 10, so why not have 13 full moons on the fourth year, intercalating an extra lunar cycle, by adding 30 days to April 10 and planting on May 10? Then on year five planting would happen on April 29, but on year six, you might add an extra lunation to bring the planting date to May 29, well beyond the last killing frost for our area. * Even with this nonuniform arrangement, you can see how a mistake was inevitable which would result in a killing frost destroying crops either before they had a chance to grow or before farmers could harvest. Your future as a calendar keeper would end badly if mistakes were made. * Astronomer priests did not rely solely on celestial happenings for their decisions. They observed the routines of animals, the return of migratory birds, insect populations, plant rejuvenation, soil moisture, temperature, and other aspects of the changing seasons to best fit a time when to announce publicly to the local farming community that planting should get underway. * The plight of early calendar keepers using the moon reminds me very much of the original reason for a Blue Moon. The Maine Farmers' Almanac kept an ecclesiastical calendar linking full moons with occurrences happening during the church year. If there were four full moons transpiring during a quarter year period, the full moon names would get out of step with the seasons. To correct for this, the third full moon in a three-month sequence which contained four full moons was named the Blue Moon, thus keeping the full moon names in step with the church year. Millennia ago, it was a little more complicated with much higher stakes, but somehow civilizations and cultures managed to survive and prosper. They all eventually adopted a solar calendar for farming and civil functions, but not necessarily religious events. Ad Astra!

April Star Map]

[April Moon Phase Calendar]