Here are some details on the Moon’s phases, close approaches of planets and other astronomical events to look for in January.
January 1: Moon at perigee (97%) at 4:51 p.m. EST, when it reaches its closest point to Earth (360,361 km).
January 3: Full Moon (100%) at 5:02 a.m. EST.
January 3: Conjunction – Close approach of Jupiter (mag –2.7) and the Moon (99%).
The pair will rise in the east at sunset, culminate around midnight and remain visible throughout the night.
January 3: Peak of the Quadrantids meteor shower around 6 a.m., before sunrise. Viewing conditions will be poor due to the Full Moon and low meteor activity—about 2 meteors per hour (in Montréal) or 5 per hour under ideal conditions. The shower will appear to originate from the constellation Boötes (radiant).
January 4: Conjunction – Close approach of the Moon (98%) and the open star cluster M44 (the Beehive). Visible in the east from moonrise and throughout the night.
January 6: Mercury at aphelion. Mercury’s 88-day orbit around the Sun will take it to a distance of 69,817,445 km from the Sun—its aphelion, the point farthest from our star.
January 6: Venus at superior solar conjunction. Venus will pass behind the Sun (a superior conjunction occurs approximately every 584 days): it will be invisible for several weeks, then return as an evening planet. At its closest apparent position, Venus will be separated from the Sun by only 0°42′, rendering it completely unobservable for several weeks, lost in the Sun’s glare.
Note: Never observe the Sun with the naked eye, even with binoculars or a telescope.
January 9: Mars at superior solar conjunction. Mars will pass close to the Sun in the sky as its orbit carries it to the far side of the Solar System relative to Earth. At its closest apparent position, Mars will be separated from the Sun by only 0°56′, rendering it completely unobservable for several weeks, lost in the Sun’s glare. It will reappear in the morning sky a few weeks later.
January 9: Jupiter at perigee. Jupiter’s orbit around the Sun will bring it to its closest point to Earth—its perigee—at a distance of 740,679,835 km. As a result, Jupiter will lie almost exactly opposite the Sun in the sky—a configuration known as opposition (on January 10)—during which it will culminate around midnight and remain visible for much of the night. Each perigee of Jupiter is associated with a nearly simultaneous opposition. On this occasion, Jupiter will reach a maximum apparent diameter of 45.6″ at its closest position and a maximum brightness of magnitude −2.7.
January 10: Jupiter at opposition.
January 10: Last Quarter Moon (50%) at 10:48 a.m. EST.
January 13: Moon at apogee (23%) at 3:52 p.m. EST—its farthest point from Earth (405,405 km).
January 18: New Moon (0%) at 2:51 p.m. EST.
January 21: Mercury at superior solar conjunction. Mercury will pass very close to the Sun in the sky as its orbit carries it to the far side of the Solar System relative to Earth. This marks the end of Mercury’s morning appearance, as it will become an evening planet in the coming weeks. At its closest apparent position, Mercury will be separated from the Sun by only 2°03′, rendering it completely unobservable for several weeks, lost in the Sun’s glare.
January 22: Venus at aphelion. Venus’s 225-day orbit around the Sun will take it to its farthest point from the Sun—its aphelion—at a distance of 108,942,780 km. In practice, Venus’s orbit is very close to being circular; its distance from the Sun varies by only about 1.5% between perihelion and aphelion. This makes Venus’s orbit the most “circular” of all the planets in the Solar System. As a result, its surface receives nearly the same amount of energy from the Sun at perihelion (closest approach) as at aphelion (greatest distance).
January 23: Conjunction – Close approach of the Moon (26%), Neptune (mag +7.81) and Saturn (mag +1.03). Both planets lie slightly below and to the right of the Moon. Visibility: Saturn can be seen with the naked eye; Neptune and Uranus with a small telescope.
January 25: First Quarter Moon (50%) at 11:47 p.m. EST.
January 27: Conjunction – Close approach of the Moon (70%), the open star cluster M45 (the Pleiades) and Uranus (mag +5.8). Visibility: from sunset until the trio sets, around 1 a.m. Observing tips: M45 is visible to the naked eye (magnificent to see with binoculars); Uranus can be found with binoculars or a small telescope.
January 29: Moon at perigee (88%) at 4:51 p.m. EST, when it reaches its closest point to Earth (365,894 km).
January 30: Conjunction – Close approach of the Moon (95%) and Jupiter (mag +2.63). Jupiter will lie below and slightly to the right of the Moon. Visibility: from sunset; Jupiter will culminate around midnight and remain visible throughout the night. Observing tips: Jupiter is visible to the naked eye; binoculars reveal its Galilean moons.
