Transient Events That Can Give Us a Good Enough Reason to Get Outside and Do a Little Observing
All month: nearly half the planets are on vacation this month, hidden from sight in the Sun’s glare. Mercury might still be a viable (but difficult) target New Year’s morning, sitting less than 2° above the SE horizon a half hour before sunrise, but it’s well on its way to superior conjunction on Jan 21 and won’t return as a sunset target until late February. Venus is also off the menu until late February, after it passes its own superior conjunction on Jan 6. Mars has already been in hiding for a couple months. It will reach conjunction with the Sun on Jan 9 and finally reappear in the evening sky in May. Saturn and Neptune are well past their best, setting around 11 pm as January arrives and 9 pm as it ends, so you’ll have to enjoy them in the early evening while you still can. Saturn will spend the month between mag 1.0 and 1.2 with a disk around 17 arcseconds wide; the rings are still close enough to edge-on to be interesting, starting the month with only a 1° tilt from our perspective and opening slightly to 2.2° by month’s end. Neptune’s blue disk measures just over 2 arcseconds this month and glows at mag 7.8. It lies very close to Saturn all month: the two planets are separated by 3.5° on Jan 1 and 1.7° on Jan 31. Although they’ll fit in the same binocular or finderscope field, it won’t necessarily be easy to see them both at once, since Saturn is roughly 500 times as bright as Neptune. Mighty Jupiter takes advantage of the other planets’ absence by staying out all night, reaching impressive elevations up to 70° throughout the month and coming to opposition on Jan 10. As 2026 begins, the big planet rises in evening twilight just after 5 pm and sets almost an hour after the Sun comes up; at the end of the month it rises in the mid-afternoon and sets more than an hour before sunrise. It blazes at mag -2.7 at opposition, and its 46 arcsecond disk loses only 0.1 mag of brilliance by month’s end. That leaves Uranus, whose pale blue-green disk shines at mag 5.6 and spans almost 4 arcseconds this month. It spends the month just 6° south of The Pleiades (M45). Uranus stays up until 4 am as January begins and 2 am as it ends, giving you plenty of time to catch a glimpse of it (and its gorgeous starry neighbors) in your favorite binos. Among the asteroids, minor planet 1 Ceres continues its trek across Cetus in evening twilight, while main belt asteroid 44 Nysa reaches opposition in Cancer at mag 8.6 on Jan 23. This month’s charts will show you where to find both of them, as well as Neptune and Uranus.
Jan 1: celebrate the arrival of 2026 by watching Callisto pop out from behind the disk of Jupiter. It’ll start out like a fresh pimple on the planet’s NE limb at 8:08 pm CST and fully emerge over the following 10 minutes. Callisto is the most distant Galilean moon and usually appears to pass above or below the Jovian disk from our perspective, but it can hide behind the disk (or transit it) near opposition.
Jan 3: Earth is at perihelion (its closest distance from the Sun), although it’s unlikely that you’d guess that from the temperature. At dusk (around 5 pm CST), the full Moon rises with Jupiter 3° to its right and mag 1.2 Pollux (Beta [] Geminorum) 3° to its left. That straight line morphs into a triangle as the trio cross the sky. Later, the Quadrantids meteor shower peaks, but the full Moon will wipe out all except the brightest of them – still, since the Quadrantids usually produce a fair number of fireballs, more than a few might burn through the lunar glow, although you probably won’t see more than 5-8 meteors per hour even from a dark site this year.
Jan 6: it’s a busy evening around Jupiter tonight. Io starts the show, slipping behind Jove’s upper right edge in twilight at 5:10 pm, while still less than 4° above the ENE horizon. It slowly peeks out from behind the planet’s lower left limb when they’re 30° above the horizon at 7:33 pm CST, fully emerging three minutes later.
Meanwhile, Ganymede is approaching the planet: its shadow transits the disk from 8:03 to 11:20 pm, followed by Ganymede itself from 8:23 to 11:40 pm. While that’s happening, take a few minutes to look 12° above the eastern horizon starting at 9:50 pm, when mag 3.8 Rho () Leonis will slowly emerge from behind the narrow dark edge of the 82% lit gibbous Moon, like a single headlight pointing upward as the Moon ascends.
Jan 7: Europa gets its turn to show off in front of Jupiter tonight. Its shadow makes the crossing from 10:37 pm to 1:28 am CST, followed by the watery moon itself from 10:43 pm to 1:34 am.
Jan 9: Jupiter reaches opposition after midnight tonight (at 2:34 am CST), and in a remarkably rare event, Callisto will transit Jupiter’s disk precisely at opposition – which means that the moon will be superimposed on its own umbral shadow as they transit the planet in almost perfect tandem. Part of the moon’s lighter penumbral shadow will extend slightly farther south than the moon’s disk – but paradoxically, since Callisto has an extremely low albedo, making it appear as dark as the umbral shadow of the other Galilean moons, the protruding penumbral shadow may appear lighter than the disk of Callisto itself. Ingress will take about 10 minutes after Callisto’s leading edge begins to bite into the Jovian disk at 1:01 am CST. While that’s happening, at 1:03 am, mag 4.8 Psi () Virginis will emerge from behind the dark edge of the third quarter Moon 10° above the ESE horizon. Back on Jupiter, Callisto’s transit will continue until 4:56 am.
Jan 12: since it’s now after opposition, the Jovian moons precede their shadows across the planet rather than following them. Tonight, as if to demonstrate how that’s done, Io treks across Jupiter from 9:41 to 11:57 pm CST, followed by its shadow from 9:45 pm to 12:01 am.
Jan 14: early risers get a colorful view this morning as ruddy red Antares (Alpha [] Scorpii) rises at 4:30 am CST, with a slim crescent Moon providing a silver accent just 3° to the star’s upper right. The pair reach 15° elevation before the brightening twilight erases the scene around 6:30 am. Use binoculars to see the color contrast well.
Jan 19-20: new Moon arrived Jan 18 at 1:52 pm CST, so at 5:20 pm Jan 19 (a half hour after sunset) it will be a challenging target: 1.1 days old, 1.2% illuminated, 4° above the WSW horizon, and 4° left of the spot where the Sun went down – and you’ll only have 20 minutes to find it before it sets. It will be a more reasonable project at the same time Jan 20: 2.1 days old, 4.5% lit, almost 15° above the horizon, 9° left of the sunset point – and you’ll have plenty of time to hunt it down before it finally sets at 6:51 pm.
Jan 22: look SW at dusk to find a narrow crescent Moon 6° below left of Saturn. The planet chases the Moon towards the horizon until it sets a few minutes after 9 pm.
Jan 26: catch another Callisto transit tonight, as the dark moon crosses the face of Jupiter from before sunset until 7:04 pm CST; its shadow begins a transit at that same time, which lasts until 11:02 pm. If you’re up late, watch Io march across the Jovian disk from 1:09 to 3:25 am, followed by its shadow from 1:34 to 3:50 am.
Jan 27: look high in the SE sky in evening twilight tonight to catch the gibbous Moon sidling up close to The Pleiades (M45). They’ll be separated by less than 2° at 5:30 pm CST, and although they’ll slowly drift apart as the night goes on, they’ll remain within a 5° binocular field until midnight. You’ll need binoculars or a telescope to see the cluster’s brilliant stars in the strong moonglow.
Rick Gering / January 2026