A stargazer’s guide to seeing the full moon transit Mars and a new arrival

On By Littum

The first full moon of the year will slide across the sky on Monday evening. For lucky stargazers in some parts of the world, it will also pass in front of the brighter-red-than-usual Mars in an event known as a lunar occultation.

But that’s not all January’s sky has to offer. A new comet, expected to be the brightest of the yearwill make its closest approach to the sun on Monday – although it will be difficult to spot, at least in the northern sky.

According to NASAa lunar occultation occurs when the moon passes in front of an object, like a distant planet, that appears much smaller in the sky. An occultation is similar to a solar eclipse – when the moon hides the sun – but much less magnificent.

Lunar occultations can happen several times a year and when the moon is in any phase. Earlier this month, a crescent moon that glided over Saturn was visible to people in Europe, northern Africa and parts of Greenland and Russia.

Mars has appeared larger and brighter in the night sky as it approaches Earth. It is approaching what is known as opposition, which occurs when Mars is on the opposite side of Earth from the Sun. During opposition, Mars is closer to us than usual and its face is fully illuminated by the Sun as seen from our world, providing a spectacular view of the Red Planet.

Mars is in opposition every 26 months. This year it reaches opposition on January 15th at 9:32 PM Eastern Time. But the planet has been becomes steadily more brilliant since November.

Only people in North America and parts of Africa will be able to see the moon occult Mars on Monday. Elsewhere, Mars will just appear close to the moon, a celestial event known as a conjunction. The occultation will last more than an hour in some places and will be visible to the naked eye, although binoculars or a telescope will improve visibility.

The event begins at different times depending on where you live. According to one diagram published by the International Occultation Timing Association, Mars will disappear behind the moon on Monday at 18.21 in Seattle, at 21.16 in Washington, DC and at 21:21 in New York City, all local times. Observers in Montreal will see the occultation starting at 21.25 and in Accra, Ghana, at 04.53 before sunrise on Tuesday.

Comet ATLAS, or C/2024 G3 to astronomers, was spotted last April by the Asteroid Terrestrial-impact Last Alert System and shares the name of many other comets discovered by the network of telescopes, including Tsuchinshan-ATLAS, which blazed across the sky in late October.

Like all comets, C/2024 G3 is a frozen chunk of material left over from the formation of the Solar System that has begun to melt as it approaches the Sun. It will reach perihelion, or its closest approach to the Sun, on January 13, coming within 8.4 million miles of the Sun’s surface.

Some comets disintegrate from the heat. But if they survive the encounter, perihelion is when they’re expected to be brightest — although being so close to the Sun can make them hard to see.

Some Northern Hemisphere observers have already spotted Comet ATLAS, a fuzzy dot with a short tail, low on the eastern horizon before sunrise. Because of its height and the light of dawn, it is difficult to see, especially without binoculars or a telescope.

Closer to perihelion, those with an unobstructed view of the western horizon may catch the comet in the evening near the setting sun. Interactive star maps like this one can help you figure out where and when to look.

If Comet ATLAS survives perihelion, it will migrate into the Southern Hemisphere sky in the latter half of January and be visible there in the evening after sunset. As the comet moves away from the sun, it will climb higher in the sky, but also become fainter each day.