Skywatch Line for Friday, January 30, through Sunday, February 1, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, January 30, through Sunday, February 1, written by Sam Salem.
On Friday, Sun rises at 7:12am and sets at 5:06pm; Moon sets at 5:46am and rises at 2:19pm.
On Friday and Saturday evenings, the waxing gibbous Moon will lie near Jupiter and the twin stars of Gemini, Castor and Pollux, and Procyon, the brightest star in constellation Canis Minor.
Full moon will occur at 5:09pm on Sunday. It rises almost exactly at sunset. Look for the bright, round full Moon climbing in the east around sunset as twilight falls. The full Moon will glow high in the south near midnight and drop low in the west before sunrise. The full Moon will glow near Regulus, the brightest star in constellation Leo. In full darkness see the Moon upper right of the Sickle of Leo. By midnight the scene has rotated so the Moon is directly right of the Sickle.
Jupiter, magnitude –2.6, shines in the Pollux stick figure of the Gemini twins. Despite the bright moonlight, Jupiter should still look excellent through a telescope. Its disk stretches 46” and will show off detail such as alternating light and dark cloud bands. In a telescope, for much of the evening, all four Galilean moons are visible west of the planet. Callisto is farthest west, with Ganymede to its east. Much closer to Jupiter, Io and Europa. Europa passes due north of Io shortly after 8:30pm. Prior to this time, Europa is farther west than Io. Afterward, Europa is closer to Jupiter and closing in. Europa disappears behind Jupiter’s northwestern limb in an occultation shortly after 12:30am.
Saturn, magnitude +1.1 at the Aquarius-Pisces border, is the brightest object in the southwest at nightfall, lower left of the Great Square of Pegasus. It descends through the evening and sets in the west around 9 pm. In a telescope Saturn’s rings are still very thin but gradually opening up. They’re now tilted 2° to our line of sight. The rings’ thin black shadow on Saturn’s globe is slowly widening too.
Through the moonlight after nightfall the Great Square of Pegasus is sinking in the west, tipped onto one corner with brighter Saturn glowing to its lower left. Meanwhile the Big Dipper is creeping up in the north-northeast, tipping up on its handle.
On Sunday, Algol, in constellation Perseus, should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 7:36 pm. It takes several more hours to fully re-brighten.