by Geoff Chester, USNO Public Affairs | 03 January 2024 Jupiter, with Ganymede, Europa, and their shadows, 2023 December 30, 23:43 UT Imaged with a Celestron 23.5-cm (9.25-inch) f/10 Schmidt-Cassegrain telescope, Antares 1.6X 2-inch Barlow lens, and a ZWO ASI183MC CMOS imager from Alexandria, Virginia Happy 2024! This is an expanded installment of “The Sky This Week” since I will be attending the annual winter meeting of the American Astronomical Society next week. The Moon wanes in the morning sky this week, passing through the rising spring and summer constellations as she dives southward along the ecliptic. First Quarter occurs on the 3rd at 11:30 pm Eastern Standard Time. New Moon will fall on the 11th at 6:57 am EST. Look for Luna’s slender crescent south of the bright planet Venus before dawn on the morning of the 8th. If you have binoculars, look just east of the lunar crescent for the reddish glow of the star Antares. Once the Moon returns to the evening sky, you will find her to the east of Saturn on the evening of the 14th. Earth reaches perihelion on the 2nd at 7:39 pm EST. At this moment the center of the Earth will be 147,100,649.4 kilometers (91,404,105.9 miles) from the center of the Sun. Fortunately for us, Earth’s orbit is very nearly circular. When we reach aphelion in July we will be just over 3 million miles farther from the daystar. This is the week when we here in temperate northern latitudes experience the year’s latest sunrises. Here in Washington Old Sol greets early risers at 7:27 am EST from now until the morning of the 12th, when sunrise begins to trend earlier. However, sunset now occurs at around 5:00 pm, some 15 minutes later than it did back in early December, so the days are definitely getting longer. The year’s first meteor shower peaks in the pre-dawn hours of the 4th. The Quadrantids can often be the most productive shower of the year, but the peak of activity only lasts for a few hours. This year the peak hours favor the eastern United States, roughly between 1:00 am and dawn. The radiant for the shower is located hear the “handle” of the Big Dipper asterism, the site of the now-defunct constellation of Quadrans Muralis. Under dark skies as single observer can expect to see over 100 meteors in an hour, but light from the Last Quarter Moon will limit visibility to only the brighter shower members. Fortunately, the Quadrantids tend to be fairly bright and are known to produce frequent “fireballs”. The meteors are relatively slow, so they take a few seconds to cross the sky. The 2024 Globe at Night observing campaign gets underway this week and runs through the evening of the 11th. This citizen-science program aims to bring awareness of the disappearance of the night sky and the effects that light pollution has on life on Earth. Participation is simple. Each month throughout the year there is a different featured constellation to identify and observe. Compare your views with the charts on the program’s web app, then submit your observation. The featured constellation for January is Orion, which is probably the most familiar star pattern in the sky. Orion is easy to spot from just about anywhere thanks to his abundance of bright, colorful stars. Of the 35 brightest stars in the sky, five may be found in Orion. The new year finds Saturn lurking in the southwestern sky as evening twilight fades. The ringed planet only spends a couple of hours in a favorable position for telescopic perusal. As the week opens he sets at around 9:00 pm. By the 15th he disappears at 8:23 pm. Get your last looks at him now. When he returns to the evening sky in late summer he’ll look quite different. Jupiter still dominates the evening hours. He pops into view shortly after sunset high in the eastern sky, and cruises over the meridian at around 7:30 pm. The giant planet reached the second stationary point in this apparition on December 31st. He will gradually resume direct eastward motion along the ecliptic over the next few weeks, crossing the constellation of Aries, the Ram as he heads for a rendezvous with Taurus late this coming fall. You still have plenty of time to get a leisurely look at Old Jove through the telescope; he’ll be prominent for the next couple of months. Venus continues her dive to the southern reaches of the ecliptic. During the first weeks of January she passes through the northern reaches of the constellation Scorpius. She gets a visit from the waning crescent Moon before dawn on the 8th. You’ll need a good exposure to the southeast horizon to catch this event, but it should make for a good photo opportunity. The elusive planet Mercury may be found about 10 degrees above the southeastern horizon about 45 minutes before sunrise. Use binoculars to look for his red-hued glow. He reaches his greatest elongation from the Sun on the 12th, but he is best seen before that date.