StarWatch Astronomy

StarWatch 1477 for the week of 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 here: https://www.astronomy.org/StarWatch/December/index-12-24.html #12-8-24 * 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!

Gary A. Becker – [email protected] or [email protected]

Moravian University Astronomy – astronomy.org

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StarWatch 1476 for the week of 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, Ta**us 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 Ta**us. Ruddy Mars is a respectable 16 degrees above the horizon in Cancer the Crab. See a map ( https://www.astronomy.org/StarWatch/December/index-12-24.html #12-1-24 ) 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 Ta**us 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!

Gary A. Becker – [email protected] or [email protected]

Moravian University Astronomy – astronomy.org