Venus has been a brilliant point of light in the west after sunset for a few months, but in January it disappears on its way to becoming a morning object. Say good-bye to it on January 2 when the crescent moon floats just above Venus before it joins the sun.
Jupiter will be the planet to watch in January, shining at magnitude -2.7 in the constellation Gemini. Jupiter reaches opposition on January 5, rising at sunset and setting at sunrise. On this date, use a telescope to see the volcanic moon Io emerge from behind Jupiter. The other three Galilean moons are already stretched out in a line on the opposite side of the giant planet, from Europa to Ganymede to Callisto.
On January 14, the moon and Jupiter come within about five degrees of each other. The moon will reach full phase the next night. January’s full moon, the Wolf Moon, occurs at 8:52 pm PST on January 15, just three hours after apogee, when the moon is farthest from Earth in its orbit. Therefore, January’s full moon is the smallest of the year.