Friday, January 20
Just before midnight strikes, Jupiter pokes above the eastern horizon. The giant planet resides in central Virgo, 4° due north of 1st-magnitude Spica. Shining at magnitude –2.1, Jupiter appears nearly 20 times brighter than Virgo’s luminary. The planet climbs highest in the south around the time morning twilight begins, and that’s the best time to view it through a telescope. Even a small instrument reveals the gas giant’s 38"-diameter disk and four bright moons.
Saturday, January 21
Mars continues to put on a nice show these January evenings. It appears some 30° above the southwestern horizon once twilight fades to darkness, though it’s easier to find by looking 6° (about one binocular field) to the upper left of brilliant Venus. The magnitude 1.0 Red Planet currently lies among the background stars of Pisces the Fish. A telescope shows the world’s 5"-diameter disk, but you likely won’t see any surface detail.
The Moon reaches apogee, the farthest point in its orbit around Earth, at 7:14 p.m. EST. It then lies 251,602 miles (404,914 kilometers) from Earth’s center.
Sunday, January 22
Although asteroid 4 Vesta reached opposition and peak visibility last week, the brightest minor planet of 2017 still shines at 6th magnitude. That’s barely bright enough to see with the naked eye from under a dark sky, though binoculars make the task much easier. To find Vesta, start at magnitude 1.2 Pollux in northern Gemini and then drop 3.6° due south to magnitude 3.6 Kappa (k) Geminorum. Vesta lies 2.6° east of Kappa this evening.