In early January, we experience our latest sunrises of the year (except for late October and early November, when late sunrises result from the artifact of daylight saving time). Dark skies within an hour before sunup allow stargazers in this first month of 2024 to conveniently enjoy Venus, the brilliant “morning star” shining at magnitude -4 in the southeast; Mercury, to its lower left; eight to 10 stars of first magnitude or brighter scattered across the sky; and a waning moon from Jan. 1-9 (hiding one of those stars on Jan. 8), returning for a second morning engagement Jan. 25-Feb. 7.
Ranking next after Venus before dawn are three stars of magnitude zero: Arcturus, high in the southern sky; Vega, low in the northeast; and Capella, very low in the northwest. After January’s first few days, Mercury will exceed these stars in brilliance; binoculars will be handy to pick it up low in the glow of twilight.
The Big Dipper stands high in north to northwest as morning twilight brightens. Its curved handle, extended, leads to Arcturus and first-magnitude Spica, well up in the southern sky. Low in the west-northwest is a pair of stars 4.5° apart: Pollux, of magnitude 1.1, and fainter Castor, of magnitude 1.6. As Earth passes between the sun and these “Twin” stars of Gemini late in January’s second week, they’re visible all night: Low in the east-northeast at dusk, south of overhead in the middle of the night, and low in the west-northwest at dawn.
On the morning of Jan. 14, Spaceship Earth is heading toward Spica, while Pollux is at opposition to the sun.
Following Pollux by five weeks, the star Regulus, heart of Leo, the Lion, will take its turn at all-night visibility, on night of Feb. 18-19. On January mornings, find 1.4-magnitude Regulus in the western sky, 37° to the upper left of Pollux. You can also find Regulus by imagining the Big Dipper’s bowl springing a leak! The watery contents would pour onto Leo and Regulus. On New Year’s morning, a 73 percent waning gibbous moon stands 13° to the upper left of Regulus.
The moon shifts eastward through the zodiac constellations at an average rate of 13° per day. On the mornings of Jan. 4 and 5, about 10 days before Earth takes direct aim at Spica, a fat crescent moon appears near that same star.
On Jan. 7, the southeast sky hosts a beautiful display: Venus, 15° to the lower left of an 18 percent crescent moon, with the red supergiant star Antares, heart of the Scorpion, just 6° to the lower right of Venus. Binoculars give a striking view of stars in the head of the Scorpion to the moon’s lower left, and two third-magnitude stars, the “outworks of the heart,” closely flanking Antares. Look 13°-14° to the lower left of Venus for zero-magnitude Mercury. Using binoculars, can you spot 1.4-magnitude Mars, very low in twilight, within 9° to Mercury’s lower left?
On the next morning, Jan. 8, the moon and Antares are both 6° to the lower right of Venus, but you may or may not spot Antares very close to the moon, depending exactly on when you look. That’s because the 11 percent crescent moon actually occults, or covers, Antares!
As seen from Palm Springs, the star will be covered by the leading sunlit bright edge of the moon in a dark sky shortly before 5:39 a.m., and reappear along the dark edge of the moon just before 6:33 a.m., with the moon’s dark edge invisible in very bright twilight. Antares will be easily seen with binoculars until a few minutes before immersion, but a telescope will be needed to observe the star at either of the two contact times.
On Tuesday morning, Jan. 9, the 5 percent old crescent moon, with Mercury 7° to its upper left, appears within 13° to the lower left of Venus. Antares is now in the clear, 7° to Venus’ lower right.
Three planets at dawn: Venus shines at magnitude -4 in the southeast as twilight brightens. Approaching superior conjunction on far side of the sun to be reached on June 4, Venus narrows its distance west (to the upper right) of the rising sun from 37° to 31° during January. Combined with the sun-to-Venus line making an ever-smaller angle with horizon this season, Venus drops noticeably lower each month. As Venus recedes from Earth, its phase becomes less impressive, from 78% lit and 14” (arcseconds) across on Jan. 1, to 86% and 12” on Jan. 31. Follow Venus going 1.2° east per day against the background: 1.0° north of Beta in the head of Scorpius on Jan. 1; 6.3° north of Antares on Jan. 7; and 3° north of Lambda Sagittarii, top the of Teapot, on Jan. 28. Look for Mercury in twilight, to the lower left of Venus, by 19° on Jan. 1; 15° on Jan. 5; 13° on Jan. 8; 11° on Jan. 14-22; and back up to 13° on Jan. 31. Mercury brightens from magnitude +0.4 on Jan. 1; to magnitude 0.0 on Jan. 4; then slowly to magnitude -0.3 by Jan. 31. Mercury climbs highest in twilight around Jan. 8 and reaches greatest elongation, 23.5° west of the sun, on Jan. 12. Use binoculars to locate faint, gradually emerging Mars(magnitude +1.4), 5° below Mercury on Dec. 30, and then to Mercury’s lower left through Jan. 26. Mars reaches its maximum distance from Mercury this month, 8.6° to the lower left, on Jan. 7-8. On Jan. 27, Mars appears only 1/4° to the lower right of Mercury. Thereafter, Mars appears to Mercury’s upper right as our solar system’s innermost planet drops away toward superior conjunction on the far side of the sun in late February.
Evening planets, moon and stars: At dusk, Jupiter shines at magnitude -2.6 to-2.4 in Aries, high in the southeast to south-southwest. Saturn, at magnitude +0.9 to +1.0 in Aquarius, sinks through the southwest toward the west-southwest horizon. Saturn’s rings look “skinny” now, only 9.1° to 7.7° from edge-on. In the morning sky during spring 2025, they’ll be presented edgewise in turn to Earth and the sun, and will disappear. The new moon occurs on Jan. 11 at 3:57 a.m., setting up an easy view of a 4 percent young crescent moon within 38 hours later, low in the southwest to west-southwest at dusk on Jan. 12. The waxing moon skips past Saturn Jan. 13-14, and past Jupiter Jan. 17-18. On Feb. 20, the gibbous moon passes a wide 9° north of Aldebaran, eye of Taurus and follower of the Pleiades. Approaching full, the moon skips past Castor and Pollux Jan. 23-24.
Evening stars: The Summer Triangle of Vega, Deneb and Altair is visible at dusk through midmonth. Before Altair, its southernmost member, sets just north of west, check the east-southeast for the rising of Sirius, the Dog Star. (You’ll need unobstructed views in both directions.) To find Sirius, extend Orion’s belt downward toward the horizon. To the left of Sirius and a little higher, look for Procyon, the “before the dog” or “little dog” star, and Betelgeuse, Orion’s shoulder, forming the nearly equilateral Winter Triangle with the two dog stars. After Sirius rises and before Altair sets, the six stars of the Summer and Winter Triangles, plus five additional stars of first magnitude or brighter (totaling 11), are visible simultaneously.
After passing full on Jan. 25, the moon rises later in the evening and returns to the morning sky. Find the waning gibbous moon at dawn, near Regulus on Jan. 27 and near Spica on Feb. 1.
The Astronomical Society of the Desert will host a star party on Saturday, Jan. 6, at the Santa Rosa and San Jacinto Mountains National Monument Visitor Center; and Saturday, Jan. 13, at Sawmill Trailhead, a site in the Santa Rosa Mountains at elevation 4,000 feet. For dates and times of these and other star parties, and maps and directions to the two sites, visit astrorx.org.
The Abrams Planetarium Sky Calendar is available by subscription from www.abramsplanetarium.org/skycalendar. Each monthly issue consists of a calendar page illustrating events such as mentioned in this article, and an evening sky map. For $12 per year, subscribers receive quarterly mailings, each containing three monthly issues.
Robert Victor originated the Abrams Planetarium monthly Sky Calendar in October 1968 and still helps to produce an occasional issue. He enjoys being outdoors sharing the beauty of the night sky and other wonders of nature. Robert Miller, who provided the evening and morning twilight charts, did graduate work in planetarium science, and later astronomy and computer science at Michigan State University, and remains active in research and public outreach in astronomy.
