StarWatch: Moravian University Astronomy

DECEMBER 2024

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

lunar phases

1476 DECEMBER 1, 2024: Winter's Stars Start to Sizzle: Those long-awaited snowflakes have finally fallen on my hometown, and the dry spell has been broken although a significant deficit in precipitation still remains. November is always the month of transition. We've been fortunate this autumn with above-normal temperatures and many cloud-free and temperate nights. However as December dawns, so debuts the colder and cloudier weather season. It is also the dawning of the winter sky rising in the east at a more respectable hour. Yes, summer constellations like Lyra the Harp, Cygnus the Swan, and Altair the Eagle are still visible, crowding the heavens low in the west, but by 10 p.m., only Cygnus is left standing like a diminished cross in the northwest. * [Before moving to the eastern heavens and the winter constellations on the rise, make sure to witness the planet Venus and the Moon in the southwestern sky on Wednesday, December 4, between 5-6 p.m. A thin waxing crescent moon and the goddess of love, the second and third brightest sky objects will be in conjunction (together) low in the SW. Binoculars will make your observation more spectacular.] * While the summer constellations are disappearing and the fall star patterns are headed westward, the eastern sky by 10 p.m. sizzles with the bright patterns of the winter group, Taurus the Bull, Auriga the Charioteer, the Gemini Twins, Orion the Hunter, and Canis Major and Canis Minor, the big and little dogs. In addition, there is brilliant Jupiter, the fourth brightest object of the night, positioned between the horns of Taurus. Ruddy Mars is a respectable 16 degrees above the horizon in Cancer the Crab. See a map showing the rising winter constellations at 10 p.m., and join some of the season's most luminous stars to form the famous asterism of the Heavenly "G," currently rising on its back. * Begin with Capella, of Auriga the Charioteer, to the right and slightly above Orion. A line segment stretching downward from Auriga's alpha star will intersect two bright luminaries relatively close together. You have come across the heads of the Gemini Twins, Castor (above) and Pollux. Down and to the right from Gemini will be the bright and solitary Procyon of Canis Minor, the Little Dog. Continuing right and following along the horizon will bring you to Sirius the Dog Star of Canis Major or the Big Dog. Move upward to the brightest star of the Hunter, blue supergiant Rigel (Orion's knee), and again up and towards the left to discover Aldebaran of Taurus the Bull. You can independently confirm Aldebaran's location by rocketing skyward from the three belt stars of Orion to this yellowish, giant star. Soaring downward from the belt is Sirius. * From Aldebaran, proceed earthward to the left shoulder of Orion, finding orangey (red supergiant) Betelgeuse. This path completes one of the versions of the Heavenly "G" rising on its side, a dazzling group of bright stars unlike any other. Use binoculars which gather more light than the human eye to reveal easily the colors of these stars in the northern heavens. * Although the Heavenly "G" is visible from the Southern Hemisphere at mid-latitudes, it is not entirely above the horizon until 1 a.m., and when seen, the "G" is upside down and backward. It's just not the same. Ad Astra!

1477

DECEMBER 8, 2024: Geminid Meteors Subdued by Moonlight

Maximum rates from the Geminid Meteor Shower are expected to occur on Friday evening into Saturday morning, December 13/14. It is one of the most anticipated meteor events of the year, not only because Geminids are relatively bright and plentiful, but because hourly rates have been rising over the last century. Increasing rates have sparked interest among amateurs and professionals despite the cold and often blustery wintery conditions that can be associated with this event. * Unfortunately, a nearly full moon will also be present to dampen the normally higher totals. If you plan to view brighter Geminids, I would recommend starting to observe around midnight when the star pattern of Gemini and the location from where the meteors will appear to emerge will be high (60 degrees) in the east. The moon will be nearly at the same altitude but about 45 degrees distant in the west. By facing east, you should be able to view Castor, the star near the radiant from where the meteors will be diverging, while keeping direct moonlight from distracting your vision. There will still remain a substantial amount of sky below the radiant to view brighter Geminids. See a map below. * The debris from three-mile wide 3200 Phaethon, now a member of the asteroid belt, supplies the bits of sand-sized grains that power the bright Geminid meteors. In a previous life, however, most likely Phaethon was a comet that largely lost its ices and was gravitationally maneuvered into the asteroid belt by Jupiter, supporting a theory that some asteroids are merely defunct comets. The debris released by Phaethon has been moving closer to the Earth's orbit over the past centuries, thus creating an ever stronger shower display. * When I first got into meteor observing as a young teen with my cousin John, the Geminids produced a display similar to the August Perseids. The hourly rates indicating the intensity of a meteor event that observers read about are determined by a mathematical formula that attempts to create zenithal (overhead) conditions for the entire sky, something that not even the darkest sites can provide. The zenith produces the best position for sky watching since observers look through the least amount of atmosphere, creating the darkest skies possible. There is no light pollution either. Sixty years ago, the zenithal hourly rates (ZHR) for the Geminids began increasing from 50 meteors per hour to the present 150-200 shooting stars each hour during the peak period of maximum night. That number will continue to increase through the very early twenty-second century. * If you are going to attempt to view the Geminids, it is imperative that you dress to beat the cold. Last year, I bought some jeans online, and one was delivered with a waist size two inches too big. I considered sending it back when I remembered that I would view the Geminids a few weeks later. I kept the Levis, stowing them in my winter gear observing box, and sure enough, they fit snugly after layering up for Geminid viewing. I watched for three hours with friend, Jesse Leayman, starting at 11 p.m., and by 2 a.m., when he had to depart, I was still feeling only slightly cool. You are more than halfway there if you can beat the cold on a crisp, clear Geminid night. Good meteor hunting this week even though a bright moon will be present. Ad Astra!

The nearly full moon will reduce Geminid Meteor Shower rates this year, but observers can still expect to witness shooting stars despite the harsh moonlight. Graphics by Gary A. Becker using Software Bisque's The Sky.

1478 DECEMBER 15, 2024: Unbearable Ursid Meteors This Week: Unbearable might be the best way to describe the Ursid Meteor Shower that emanates from the body of the constellation of the Little Bear. Very little is known about this cold weather phenomenon which occurs just before the busiest holiday of the year and the cloudiest period for most Mid-Atlantic locales. It also follows the euphoria of the most active annual meteor shower, the Geminids, just eight days earlier than when Ursid activity normally peaks. Ursid meteors also cannot be seen from the warmer Southern Hemisphere or from Northern Hemisphere locations near to the equator because the Little Bear (Little Dipper) is either too low in the sky or never rises above the horizon. * Ursid activity for 2024 is predicted from December 17 through the 26th, with the night and hour of maximum activity forecast to materialize on December 22 at 5 a.m. * This ungodly hour may seem like the worst possible timing to be outside looking for shooting stars. Still, it could not be a better moment for observers on the East Coast who will be in the prime location for witnessing Ursid dross ablating into the Earth's atmosphere. Ursid rates have been as numerous as 50 meteors per hour, but usually there are no more than a half dozen meteors seen each hour. However like most organized shooting star events, rates can vary depending upon whether the Earth passes through a thread or threads of denser meteoroid debris. Observers noted higher-than-average hourly counts in 2006 through 2008, 2014, and 2015. Much higher tallies were reported from 2016 through 2018. This year increased meteor activity due to a region of denser meteoroid particles has been predicted for the early evening hours of December 21 around 7 p.m. EST. Unfortunately, North America and Western Europe will be incorrectly place to witness these higher counts. The situation is analogous to driving through a rainstorm and looking out the back window which will be our location when Earth enters this increased debris thread. The impacts will favor the front windshield as the car (Earth) plows into the debris, with the back window getting almost no hits. If enhanced activity materializes, India, Pakistan, western China, Kyrgyzstan, Kazakhstan, and Russia may profit from seeing this thread of denser debris. * Meteor showers owe their existence to the dross released from active comets orbiting the sun or comets that have settled into retirement within the asteroid belt. The progenitor of the Ursids, Comet 8P/Tuttle, was discovered by Horace Parnell Tuttle (1837-1923) on January 5, 1858. The comet is periodic with a 13.6-year orbital cycle that last reached perihelion, its closest distance to the sun, on August 27, 2021. * Tuttle was an American astronomer who has 14 comets to his credit, either discovered for the first time, or recovered, comets that were first detected by other observers and then rediscovered by him during a subsequent passage around the sun. Horace Tuttle was also a Civil War veteran commissioned in the US Navy who served on numerous ships, including the monitor USS Catskill, an ironclad warship with a revolving turret, where he participated in the blockade of Charleston Harbor and the capture of the Confederate blockade runner, Deer, near the end of the war. * If you plan to observe the Ursids, be outside by 4:30 a.m. Meteors will appear to diverge from just above the bowl of the Little Dipper (body of the Little Bear), which will be about 40 degrees above the northern horizon. Polaris, the North Star, is located at the end of the handle of the Little Dipper. Focus your attention above that area, near the zenith where the sky will be the darkest. Unlike this year's Geminids which were affected by a nearly full moon, the morning of maximum activity for the Ursids will have a last quarter moon located far from the radiant, producing only about 10 percent of a full moon's brilliance. Good Ursid (Bear) hunting to all. Go below for a sky map showing the Ursid radiant. Ad Astra.

1479 DECEMBER 22, 2024: Stunning Hope Captured in the Eagle: Many spectacular images are taken with modest telescopes owned by amateurs to sophisticated orbiting observatories like Hubble and, more recently, the James Webb Space Telescope. An image like the Orion Nebula, a stellar nursery that appears like a smudge through binoculars, blossoms into an intricate web of churning, gasses, fluorescing against dark nebulae, sculpted by magnetic fields and the outpouring of energy from new born stars. The Crab Nebula, a supernova remnant, and the Pleiades, a newly formed star cluster, both found in Taurus the Bull, and the Andromeda Galaxy, are other favorites of mine that pique my imagination and confirm there is beauty and reverence in the heavens. My favorite masterpiece, though, which evokes a spiritual sense of magnificence, is the Pillars of Creation found in the summer constellation of Serpent the Snake, a group of finger-like dust clouds and glowing gas in the Eagle Nebula (M16) that are actively forming new luminaries. * In the starscapes made famous through numerous photos taken by the Hubble Space Telescope, the long, dark nebulae of gas and dust that compose the Pillars, stand out like guardians against the turquoise shaded background of a much larger scene which encompasses a new star cluster pushing outward the leftover materials of its creation, cleaning the nest of debris so its light can escape, unblemished by any obstacles. In an imaginative way the tops of the pillars remind me of outstretched hands, ready to grab starlight, when in reality, they are new stars imbedded in dust on the verge of creating their own light. * I have always believed that the environment in which you are raised helps to form your personality and nurture your aspirations and dreams. Take the Himalayas in Nepal as an example. How could anyone living near such grandeur not be influenced by their presence? So it is with me and the Pillars of Creation. Suppose you could see them each night from a nearby planet in all their glory, reaching to seize starlight in the sky? Would you not be influenced by this? * I marvel at the Pillars, one scene in so many that our telescopes and camera sensors capture. It awes me. Sometimes, we forget the power and majesty of God, creator of the universe, and all that lies therein because these objects are not present in our everyday lives. We are never physically allowed to witness them firsthand like the moon and stars that are so common in our daily existence. * This Season of Light in the domain of the year that yields the greatest darkness should make us grateful that God came to us, not only to create the galaxies and other celestial monuments that grace our cosmos, but also to become human, in the embodiment of a small child, born in a small town, and raised by parents of no special privilege. To me, these heavenly wonders in the nighttime sky attest to this love: the star that guided the magi, the array of galaxies that ponderously move throughout the universe, and the delight to be able to witness them either through the eyepiece of a telescope or in the images recorded by them; the God of Love shows us His masterpieces. Take time to look heavenward and relish in His hope for a peaceful solution to our problems. The joys and hopes of the Yule Season are upon us, welcoming all who are in search of answers. Ad Astra!

1480 DECEMBER 29, 2024: January Starts Off with a BANG!: Happy Almost 2025! With only a few days before ringing in the New Year, it was time to research various calendars to survey upcoming events for 2025. Getting beyond January, however, was impossible because several interesting events need to be addressed. * There is a beautiful occultation of Mars by the full moon during the early evening hours of the 13th (next week's StarWatch) and a plethora of planets that will be visible later in the month. However, the first event of importance is the famed Quadrantid Meteor Shower scheduled to maximize its activity on January 3 around 10 a.m. for the East Coast. * Even though the Quadrantids occur in the new year, I still consider them part of the big five meteor events of the old year: the Perseids (August 12, 2025), Orionids (October 21), Leonids (November 17), Geminids (December 14), and finally the Quadrantids (January 3, 2026). After the Quadrantids, the first notable meteor spectacle is the Lyrid shower on April 22, 2025. If a bright moon occurs in the middle of the month as it did during the autumn of 2024, then the first four showers are usually affected adversely and become nonevents because of bright moonlight. However, Quadrantids meteors will then "fly" under an essentially moonless sky. Luna will be a three-day waxing crescent setting at 8 p.m. on January 2, but full in 2026 when the Quadrantids return again. The time of maximum activity is 10 a.m., surrounding a brief four-hour window when rates are the highest. That should start around 8 a.m. EST, again after sunrise. * Still, meteor predictions are often off by several hours and sometimes much more, making the period before dawn on January 3 a prime time for observations. The East Coast could very easily be at the beginning of the sweet spot of activity that could net observers rates that average between 60 to 200 meteors per hour under perfect conditions. Because we do not live in a perfect world, I would reduce those meteor rates considerably, perhaps to 20 to 40 shooting stars per hour from suburbia. The last three years have been average, with hourly rates of about 80 shooting stars each hour, but in 2020-22, the shower peak arrived early. The shower has summited at the predicted times for the last two years. * Quadrantids also have their share of bright meteors and fireballs to keep the adrenaline pumping. They rate as having one of the brightest magnitude distributions of any annual meteor event, and their entrance velocities are relatively slow, about 41 kilometers per second, which converts to just over 25 miles per second. This slower entrance speed gives observers more time to catch them as they rapidly ablate (break up) as a fiery streak across the Earth's upper atmosphere. * The biggest issue with any winter astronomical event is the possibility of bitterly cold temperatures and snow-covered ground, blustery conditions, clouds, and just getting yourself up at some ungodly hour, like 4 a.m., to begin preparing for going out-of-doors. It's not easy. In addition with meteor science, there are no sure guarantees that success awaits the prepared. My only experience with the Quadrantids was at the base of a mountain on snow-covered ground where wind gusts blew fine-grained ice crystals into my face. The temperature was in the mid-teens. My students and I lasted about two hours before packing it in and going home. * You'll find a 2:30 a.m. locator map of the radiant below, if you are brave enough to venture outside on the morning of the 3rd. * One last note… Don't forget to check on the beautiful conjunction of Venus and the thin crescent moon in the southwest on the evening of January 3. The duo will be just over three degrees apart, a beautiful sight through binoculars or captured with the handheld steadying technology of a newer smartphone. Happy New Year! Ad Astra!