The Sky This Week for January 5 to January 8

The Sky This Week for January 5 to January 8

By Richard Talcott

 

Thursday, January 5

First Quarter Moon arrives at 2:47 p.m. EST. Our satellite rises in the east around noon local time but doesn’t become prominent until the Sun sets around 5 p.m. By 6 p.m., it appears due south and nearly two-thirds of the way to the zenith. The Moon’s half-lit orb then lies among the background stars of southern Pisces.

Friday, January 6

Jupiter dominates the morning sky in early January. The giant planet rises before 1 a.m. local time and climbs nearly halfway to the zenith in the southern sky by the time twilight begins. Jupiter shines brilliantly at magnitude –2.0 and shows a disk that spans 36″ when viewed through a telescope. A small scope also reveals the planet’s four bright moons, though you may have to hunt for one of them this morning. The shadow of volcanically active Io starts to transit Jupiter at 5:24 a.m. EST, and the moon itself begins to cross the planet’s disk at 6:37 a.m.

Saturday, January 7

The variable star Algol in Perseus appears faintest at 12:30 a.m. EST tomorrow morning, when it shines at magnitude 3.4. If you start watching it immediately after darkness falls, you can see it dim from its peak brightness (magnitude 2.1) to minimum and then rise back to maximum all in a single night. This eclipsing binary star runs through a cycle from minimum to maximum and back every 2.87 days, but the drop from peak brightness and subsequent rise lasts only about 10 hours. Algol appears in the eastern sky after sunset and passes nearly overhead around 8 p.m. local time.

The dwarf planet Pluto is in conjunction with the Sun at 2 a.m. EST. The distant world then lies on the far side of the Sun from our perspective and can’t be seen.

Sunday, January 8

Although Mercury passed between the Sun and Earth in late December, it already has returned to view before dawn. This morning, you can find the inner planet 9° above the southeastern horizon 30 minutes before sunrise. Shining at magnitude 0.2, it should show up through the twilight glow. If you don’t see it right away, binoculars will bring it into view. A telescope reveals Mercury’s 8″-diameter disk, which appears one-third illuminated.

Source

Astronomy Magazine