Celestial Marvels Unveiled: Moon Dances with Mars and Pleiades, Plus Mars Shines at Opposition!

A composite illustrates the Dec. 7, 2022, event of Mars being obscured by the Moon. While the time-lapse image creates an illusion of Mars moving, in fact, it was the Moon’s quicker relative motion that made it seem to pass in front of a stationary Mars situated in the backdrop. Credit: Alan Dyer

This month, all the significant planets are visible. Venus enjoys a splendid evening alignment with Saturn, and Jupiter is positioned high in Taurus. Uranus and Neptune are accessible through binoculars, while Mars attains opposition. Mercury becomes apparent in the early morning hours. Moreover, on the 9th, the Moon traverses the Pleiades (M45), and on the 13th, it conceals Mars in a rare occurrence.

Venus shines brilliantly in the southwestern sky post-sunset throughout the month. Beginning with a magnitude of –4.4 and rapidly increasing its brightness, it’s easily detectable as twilight approaches. On the 1st, Venus displays a disk illuminated by 55 percent measuring 22″ across. On Jan. 2 and 3, the waxing crescent Moon joins the scene, positioned 10° southwest and 4° east of the planet, respectively. On the 4th, observe that the Moon is 4° northeast of Saturn, which is approximately 13° from Venus. 

Venus attains its highest eastern elongation on Jan. 9, situated 47° from the Sun, setting nearly four hours after sunset.

The moment when Venus exhibits a 50-percent-lit disk is known as dichotomy. This moment can deviate from forecasts by as much as four days. Check on Jan. 11, the projected day of dichotomy. What do you notice?

In the days to follow, Venus narrows its distance to Saturn, being slightly less than 4° west of the gas giant on the 14th, reaching a minimum separation of just 2.2° on the 17th. By the 19th, Venus lies 2.5° directly north of the ringed planet, which shines at a magnitude of 1.1.

On the 23rd, Venus moves into western Pisces, concluding the month at 1.5° from Lambda (λ) Piscium. Its disk has expanded to 32″ across and is 38 percent illuminated.

The optimal telescopic views of Saturn are nearly over; however, a brief window remains after nightfall. Saturn rises to 30° two hours after sunset on the 1st, setting around 10 p.m. local time on that day and 8 p.m. on the 31st. It shines at a magnitude of 1.1 for most of the month, positioned south of Phi (ϕ) Aquarii.

In a telescope, Saturn’s disk measures 16″. The rings are widest at the beginning of the month, appearing at 4° and narrowing to 3° by the 31st. They will appear edge-on in March.

Titan, Saturn’s largest satellite, is easily observable with any telescope. It is located near the planet on Jan. 6, 7, 14, 15, 22, 23, 30, and 31.

Iapetus reaches its brightest western elongation, at 8′ from Saturn, on New Year’s Eve. During the first three weeks of January, it gradually moves toward superior conjunction and dims from 10th to 11th magnitude. On Jan. 20, it is situated just 47″ directly south of Saturn, a prime opportunity to locate this mysterious moon.

Neptune resides approximately 12° east of Saturn. With a brightness of magnitude 7.8, it can be detected using binoculars. At the close of January, it occupies the same binocular field as Venus, serving as a reference to locate the remote planet.

In early January, Neptune forms a lovely triangle with 20 and 24 Psc, which shine at magnitudes 5.5 and 5.9, respectively. As January advances, Neptune shifts eastward, standing 1° directly north of 24 Psc on the 29th. Venus maintains a distance of 3.5° from Neptune, remaining consistent through the 31st.

Uranus appears fixed against the backdrop of Aries as it concludes its retrograde path at the month’s end. With a magnitude of 5.7, it is an uncomplicated target for binoculars. Positioned about 8° southwest of the Pleiades, Uranus lies south of a cluster of 5th-magnitude stars, the brightest of which is 63 Arietis. Uranus is found 2.5° directly south of this star. 

This is an excellent moment to spot Uranus using a telescope, reaching heights above 60° after 8 p.m. local time. Its 4″-wide disk poses a challenge, but strive for good conditions with high magnification. It should remain visible well past midnight throughout the month.

In Taurus, Jupiter dominates the night sky, altering the familiar constellation’s look. Jupiter spends the majority of January shining at a magnitude of –2.7. As darkness envelops the sky, it rises nearly 40° high in the east, providing outstanding viewing opportunities with a telescope. It reaches its peak height just before 10 p.m. local time in early January, and two hours earlier towards the month’s end. 

On Jan. 10, the planet is 5.5° away from a waxing gibbous Moon, and on Jan. 31, it stands 5° north and a bit east of Aldebaran. The size of Jupiter’s disk reduces from 47″ on Jan. 1 to 43″ by the end of the month. Even small telescopes reveal a plethora of details. Most days, the four Galilean moons — Io, Europa, Ganymede, and Callisto — are observable; at times, one may hide behind or transit in front of the disk, along with its shadow.

Jan. 1 witnesses Io disappearing and subsequently re-emerging from Jupiter’s immense shadow. The moon vanishes behind the northwest limb shortly before 8 p.m. EST. Observe the area 12″ east of the planet to watch Io appear just prior to 10:45 p.m. EST.

Approximately 8:25 p.m. EST on the 6th, Europa starts to…

a transit. Just prior to 10 p.m. EST, its shadow becomes visible. Europa departs the disk at 11 p.m. EST; the shadow follows suit approximately an hour and a half later.

On the 16th, Io transits between 8:36 p.m. and 10:48 p.m. EST, with its shadow observable from 9:32 p.m. to 11:44 p.m. EST. As the shadow exits the western edge, Ganymede is occulted on the same side almost at the same time, taking a few minutes to vanish.

Ganymede reemerges at the northeastern edge around 1:51 a.m. EST (Jan. 17 in the Eastern and Central time zones). It subsequently slips into Jupiter’s shadow 90 minutes later. You’ll notice it beginning to fade just before 3:30 a.m. EST.

Ganymede traverses the disk on Jan. 27. Observers on the East Coast might witness the start of the transit at sunset. The moon exits beginning around 7:20 p.m. EST. The shadow commences its transit around 9:40 p.m. EST, taking several minutes to fully emerge, making it readily visible through small telescopes. The shadow transit concludes starting at 11:49 p.m. EST.

The highlight of the month is the opposition of Mars late on Jan. 15. It peaks at magnitude –1.4, shining as brightly as Sirius. Mars commences January in Cancer and traverses westward, entering Gemini by the 12th. This positions it high in the sky at approximately local midnight.

Oppositions of Mars transpire every 780 days. The planet’s diameter reaches nearly 15″. Mars’ closest approach to Earth occurs on Jan. 12, a few days prior to opposition. At this point, it is 59,703,891 miles away. (This is an aphelic opposition, not as near as a perihelic one.)

Mars will appear diminutive in telescopes smaller than 8 inches. Larger instruments provide superior views. Exercise patience while observing for moments when Mars showcases its splendor. Can you discern the North Polar Hood or the brilliant white polar cap? The former will likely dissipate this season.

Mars seems to rotate in reverse when observed at the same time each night. At 9 p.m. local time from the central U.S. (view an hour later in the East, and an hour or two earlier further west), the Olympus Mons and Tharsis Ridge region will be facing us during the first week of January. By Jan. 7, Valles Marineris will be well positioned, followed shortly by Solis Lacus. By mid-January, Sinus Meridiani takes center stage, then Syrtis Major after the 19th, with the bright Hellas basin to its south. In the final days of the month, Mars displays Mare Cimmerium.

On the 13th, Mars is obscured by the Moon. Timing is contingent on location, but the East Coast observes Mars disappearing around 9 p.m. EST; this is shortly after twilight fades in the Mountain time zone. It takes roughly 20 seconds for Mars to be entirely concealed. Along the Pacific Coast, this happens soon after moonrise during evening twilight. Mars reemerges approximately an hour later.

Mercury is observable in the early-morning sky. On Jan. 1, it is an easily identifiable object during twilight at magnitude –0.4, located 12° east of Antares. It rises to 6° in the southeastern sky by 6:30 a.m. local time.

A week later, you’ll need to wait another 15 minutes for it to achieve the same height. Scan the area with binoculars because shortly after Mercury ascends, you might glimpse the Trifid (M20) and Lagoon (M8) nebulae, positioned 2° east and southeast of the planet, respectively — at least, you might catch sight of the stars embedded within them.

There’s a considerable amount of uncertainty regarding the visibility of Comet C/2024 G3 (ATLAS) at the time of writing, but it is positioned 5° southeast of

Mercury on the same dawn (the 7th). Remain vigilant in the event that the comet surpasses projections.

Mercury is situated less than 1° north of the Lagoon Nebula on January 9, and by the 14th, it is within 15′ of M22, although this 5th-magnitude globular is obscured during twilight.

Mercury reaches a brightness of –0.5 by the 16th, but its distance from the Sun has decreased. The planet is obscured in twilight over the following days.

The Moon hides some stars in the Pleiades early on the evening of January 9. This event unfolds in darkness on the East Coast and commences in twilight further west, taking place in daylight for the Pacific time zone.

The 10-day-old Moon progresses across the southern region of the cluster; the initial star to vanish from some eastern locations is Electra, around 7 p.m. EST. Just over 20 minutes later, the 4th-magnitude Merope follows.

From Kansas City, Merope disappears at about 6 p.m. CST, but the Moon overlooks Electra. Approximately 35 minutes later from this location, the Moon arrives at Alcyone. Atlas and Pleione are occulted roughly 45 minutes later. The timing significantly varies by your location; refer to the International Occultation Timing Association’s website (www.lunar-occultations.com) or the 2025 Royal Astronomical Society of Canada’s Observer’s Handbook.

A few 7th-magnitude stars are also obscured, observable in small telescopes as they slide behind the Moon’s dark edge.

Rising Moon: Go with the flow

A new year ushers in a new crescent. When the earthshine is prominent on the 2nd, identify features known as “Full Moon” such as Tycho’s rays, brilliant Aristarchus, the aprons of Copernicus and Kepler, and naturally the lunar seas. The array of bright and dark arcs of the foreshortened craters on the illuminated crescent can be challenging to distinguish.

By the 3rd, the oval Sea of Crises north of the equator is perfectly lit. Cleomedes, named for a 1st-century Greek astronomer, is the substantial, 80-mile-wide crater gracing the northern edge of Mare Crisium. A slightly off-center suggestion of a central peak protrudes from the lava-covered floor, which is speckled with a few notable craters about 7 miles across. Increase the magnification to spot the elongated yet thin rille, termed Rima Cleomedes. Exercise patience for moments of steadiness in the atmosphere above us. These smaller details will fade under a higher Sun on the forthcoming evenings.

Observable to the naked eye over the next two weeks, Crisium appears to drift northward while the highlands recede from the southern edge. In relation to Earth’s orbit on the ecliptic, Luna arcs above it sufficiently for us to glimpse “under her chin” — astronomers refer to this visual phenomenon as optical libration. From the 11th to the 15th, search for towering mountains and shadows at the lunar south pole.

You might find it nearly as fascinating to watch the sunset shadows envelop the landscape in the evenings following the Full phase on the 13th. The inverted lighting essentially transforms this into uncharted territory. Prepare to experience it once more when the slender crescent returns on the 30th.

Meteor Watch: Kicking off the year positively

With a waxing crescent Moon in the early evening sky, the conditions align for the annual Quadrantid meteor shower. It peaks on January 3 and is best observed in the hours preceding dawn.

The Quadrantids are active between December 28 and January 12, displaying a narrow peak. The radiant ascends shortly after 9 p.m. local time, and by 4 a.m. it is approximately 45° high. Anticipate around 25 to 30 meteors per hour if the peak occurs during the dark window of your viewing location, equating to a maximum zenithal hourly rate of almost 100, establishing it as one of the finest showers of the year.

The progenitor of the Quadrantids, 2003 EH₁, was identified in 2003 by Brian Skiff at Lowell Observatory.

Comet Hunt: 2025 dawns with anticipation

You know those splendid comets that appear suddenly with so little warning that they outpace the publication deadline? We would be grateful for three of those! This year, no known interplanetary ice balls are projected to shine brighter than 10th magnitude or to be conveniently positioned.

Aspiring comet seekers with 8-inch telescopes have the opportunity to test their abilities on 333P/LINEAR, at a magnitude of 10.5, but it necessitates a reliable star chart and ephemeris to locate it in the cosmic backdrop. Concerning the North America Nebula (NGC 7000), this dim comet is situated west of Hawaii.

However, we might be fortunate just 3° south of Regulus. Comet 29P/Schwassmann–Wachmann has been known to experience outbursts from magnitude 15 to 10.5 intermittently, and then takes a fortnight to diminish back down. You will want to use at least 150x for the 1′- to 2′-wide section to capture it. Hone your skills on the “other” Leo Trio — M105, NGC 3384, and NGC 3389 — the latter being a faint magnitude 11.8, to prepare yourself before targeting the comet.

Finding Asteroids: Wandering through shadowy paths

If we allow them to, asteroids can guide us through secluded paths that lead us across captivating fields. From suburban locations, 15 Eunomia is our guiding beacon, reflecting sunlight to overshadow the majority of the distant stars of the outer Milky Way, much of which is concealed by extensive, dusty regions. Only three stars shine brighter in the area.

Under a dark sky, a landscape of stardust and corridors appears in a wide-field eyepiece. Take your time to recognize Eunomia by sketching three or four of the brightest stars and returning on another evening to observe its movement. However, the real prize is found by simply sweeping the telescope back and forth along its trajectory. Just like many Barnard dark clouds, several Lynds objects can be spotted here.

On the southern side of Castor on the 15th, traveling at 7′ per hour, 887 Alinda manifests as a magnitude 9.5 dot that should be enjoyable to track with a 4-inch telescope from suburban areas. Approaching roughly 30 times the Moon’s distance, this Amor-class asteroid never intersects our orbit — but it could in millions of years. At just over a mile in diameter, a collision would lead to regional devastation and a worldwide food crisis.

Star Dome

The illustration below depicts the celestial sphere as observed from 35° north latitude. Within the margins, you will find the cardinal directions along with their intermediate positions. To locate stars, elevate the map above you and align it so that one of the labels corresponds with the direction you are facing. The stars above the map’s horizon will now correspond to those visible in the sky.

The comprehensive sky map illustrates how the heavens appear at:
9 p.m. January 1
8 p.m. January 15
7 p.m. January 31
Planets are represented at midmonth