The Sky This Week from January 28 to February 4

Monday, January 31
Main-belt asteroid 44 Nysa is currently crossing the 45′-wide open star cluster NGC 1647 in Taurus.

You’ll find this stunning sight just 3.5° northeast of Aldebaran, the bright red 1st-magnitude eye of the Bull. Tonight, Nysa is in the center of NGC 1647, about halfway through its several-day journey across this more distant grouping of stars. Focus in on the cluster with binoculars or a telescope and sketch the points of light that you see. Then, come back within three hours or so and compare what you see now to your chart. One of those points has moved — that’s 10th-magnitude Nysa.

Taurus is full of other visual treats to enjoy while you’re waiting for Nysa to make itself known. On the southwestern side of Aldebaran is the loosely packed, young Hyades cluster, which forms a V shape on the sky often envisioned as the Bull’s nose. And some 14° northwest of Aldebaran is the sparkling Pleiades cluster (M45), a more compact young cluster of stars in which some observers see a small spoon or dipper (though it’s not to be confused with the Little Dipper in Ursa Minor!).

Plus, drop 4.5° south of the Pleiades and you’ll run right into 8th-magnitude dwarf planet 1 Ceres, located less than 1° east of 13 and 14 Tauri, a close pair of stars roughly equal in brightness.

Sunrise: 7:09 A.M.
Sunset: 5:18 P.M.
Moonrise: 7:09 A.M.
Moonset: 4:39 P.M.
Moon Phase: Waning crescent (0.5%)

Tuesday, February 1
New Moon occurs at 12:46 A.M. EST, rendering our satellite effectively invisible and giving us dark skies. That makes it the perfect night to spot the ice giant Uranus, which tonight stands just 25′ from 6th-magnitude 29 Arietis in Aries the Ram.

An hour after sunset, this region is still 64° high. It won’t set until just after local midnight. Uranus is currently in a dim region of southern Aries. You can roughly find its location by pinpointing Hamal (the Ram’s brightest star) and Menkar to its southeast in Cetus the Whale. These two stars are about 23.5° apart, and Uranus lies roughly halfway on a line drawn between them. The planet is magnitude 5.8 — just bright enough to spot with the naked eye if you’re in a clear, dark location. It will be easy to find with binoculars or a telescope; once you do, compare it to 29 Arietis and see if you can discern the slight (0.2 magnitude) brightness difference between them.

Sunrise: 7:08 A.M.
Sunset: 5:20 P.M.
Moonrise: 7:52 A.M.
Moonset: 5:55 P.M.
Moon Phase: Waxing crescent (1%)

Wednesday, February 2
The Moon passes 4° south of Jupiter at 4 P.M. EST, signaling one of the last, best views of this giant planet before it becomes hard to spot by next week. Turn west as soon as the Sun sets and the sky starts growing dark to find the pair in Aquarius. You’ll want to be quick — an hour after the Sun sets, they’re less than 10° high.

Jupiter blazes a bright magnitude –2, hard to miss in the twilight. The Moon, which appears to Jupiter’s lower left in the sky, is a mere 4 percent lit, with just its eastern limb on display. Zoom in on the planet with a telescope and you’ll see that all four of its Galilean moons are on display. Ganymede sits alone to Jupiter’s east, while (from closest to farthest) Io, Europa, and Callisto stretch out to the west. If your seeing (atmospheric steadiness) is good enough, you may also be able to make out the alternating light and dark bands of Jupiter’s cloud belts on the planet’s 34″-wide disk. Your chances will be better earlier in the evening, before this target sinks too low into the thicker atmosphere near the horizon.

Sunrise: 7:08 A.M.
Sunset: 5:21 P.M.
Moonrise: 8:27 A.M.
Moonset: 7:09 P.M.
Moon Phase: Waxing crescent (3%)

Thursday February 3
The delicately waxing Moon passes 4° south of Neptune at 4 P.M. EST. Look west as soon as the sky is dark to spot our solar system’s farthest planet, where it’s still in roughly the same configuration with our satellite. Neptune glows a dim magnitude 7.9, so you’ll want binoculars or a telescope to spot it in eastern Aquarius. You can use the 6th-magnitude star Phi (ϕ) Aquarii to guide you once you’re close — tonight, this star sits 1.5° due south of the planet. When you do find Neptune, expect to see a “flat,” dim star. Look closely and you may be able to determine that it isn’t a star at all, which would appear as a pointlike source. Instead, the planet shows off a tiny disk just 2″ wide.

Mercury is stationary at 5 P.M. EST in Sagittarius. After today, it will begin quickly tracking east against the background stars.

Sunrise: 7:07 A.M.
Sunset: 5:22 P.M.
Moonrise: 8:56 A.M.
Moonset: 8:20 P.M.
Moon Phase: Waxing crescent (8%)