The Moon, Mars, and Uranus Gather in the Evening Sky

~2 min

Last week the observers had an opportunity to enjoy the spectacular duo of the thin crescent Moon and the elusive planet Mercury. The fascinating astronomical event that awaits us this week will be the gathering of the Moon, Mars, and Uranus in the evening sky. Wonder how and when to see this beautiful astronomical trio? Read on!

Close approach of the Moon, Mars, and Uranus

The close approach of the Moon, Mars, and Uranus will take place on January 21, 2021, at 04:49 a.m. EST (09:49 GMT). Our natural satellite, the Red Planet, and the blue-green ice giant will gather in the constellation Aries, shining with magnitudes of -11.9, 0.2, and 5.8, respectively.

This week, the Moon will reach the first quarter phase — it will happen on January 20, at 4:02 p.m. EST (21:02 GMT). Mars shines as bright as the sky’s most brilliant stars; the Red Planet reaches its highest point in the sky around 7:00 p.m. local time. You can easily see it with the naked eye as a reddish “star” shining in the Moon’s vicinity. On the contrary, the distant planet Uranus will be almost impossible to view with the unaided eye. The ice giant is more than 150 times fainter than Mars. Use the binoculars or backyard telescopes to spot it.

Moreover, on January 21, at 6:34 p.m. EST (23:34 GMT), Mars will pass 1°43' to the north of Uranus. The planets will lie close enough to each other to fit in a single binocular field of view for about the next week. Don’t miss the opportunity to witness this astronomical duo easily visible through a small telescope!

Take advantage of the stargazing guide Star Walk 2 to easily find the Moon, Mars, and Uranus in the sky above you. Find out what's up with the Moon tonight, learn what planets are visible from your location, and get more information about the phases of the Moon with Star Walk 2!

Mars and Uranus at eastern quadrature

In the next few weeks, Uranus and then Mars will reach the eastern quadrature, lying 90° east of the Sun. The term “quadrature'' is applied to the position of a superior planet (situated further from the Sun than the Earth) or the Moon at its first and last quarter phases. At quadrature, the position of a superior planet makes a right angle with that of the Sun, as viewed from the Earth.

The superior planets are best seen at oppositions when the celestial longitude or elongation of a planet differs by 180° from that of the Sun. At quadratures, a superior planet shows its gibbous phase so that the terrestrial observers can see more than half but not all of its disk illuminated.

The ice giant Uranus will be at the eastern quadrature on January 26, while the Red Planet will reach the quadrature about a week later — on February 1. A telescope will reveal Mars in its smallest phase at around quadrature, though its disk will appear 89% illuminated by the Sun.

Wishing you clear skies and happy stargazing!