Io’s and Ganymede’s shadows trek across Jupiter’s disk together the evening of January 17. Illustration by Astronomy: Roen Kelly
The new year opens with great views of several bright planets. Two stand out: Jupiter dominates the sky after sundown, and Venus gleams high in the darkness before dawn. View more closely and you can find Uranus through binoculars as it lurks in Jupiter’s vicinity. And Mercury pops into view below Venus in early January; the two inner planets reach their greatest elongations from the Sun within a day of each other. That leaves Saturn as the last of January’s bright planets. The ringed w…
