January kicks off with an incredible opportunity to see Jupiter and its four largest moons with the naked eye, with the best viewing happening on January 10th when the solar system’s largest planet reaches opposition, meaning it’s positioned on the other side of the sky from the Sun from Earth’s perspective. Generally across US time zones, Jupiter will crest the eastern horizon at sundown and continue to climb until midnight when it reaches the highest point in the sky, making it visible with the naked eye and easy to spot. With a pair of binoculars or a telescope, stargazers can see Io, Ganymede, Europa, and Callisto, the four largest moons of Jupiter that were first identified by Galileo Galilei in 1610 and are now called the Galilean Moons. Io is the most volcanic world in the solar system while Ganymede is the largest satellite, and Callisto appears spotted because of its many craters, each offering unique features that amateur astronomers can observe.
The viewing will happen seven days after the full Wolf Moon, which will be a supermoon this month and peak at 2:00 a.m. Pacific time, so there may be some light pollution from the waning half moon. The Wolf Moon gets its name because it was believed that wolves were more likely to howl in North American lands in January, adding to the mystical quality of the winter night sky. Opposition happens when a planet is directly opposite the Sun in Earth’s sky, making it appear at its brightest and largest, giving casual observers their best chance all year to witness the majesty of Jupiter’s system. This is a perfect opportunity to get outside in the dark hours and witness the same celestial wonders that inspired Galileo over 400 years ago, proving that some of nature’s most incredible shows are completely free.
