This is Dudley Observatory’s Skywatch Line for Friday, January 26, through Sunday, January 28, written by Sam Salem.
On Friday, Sun rises at 7:16am and sets at 5:00pm; Moon sets at 8:10am and rises at 5:54pm.
On the Friday and Saturday evenings, the waning gibbous Moon will float near Regulus, the brightest star in Leo the Lion, marking the bottom of the backward question mark asterism, the Sickle. They’ll be visible most of the night.
On Saturday morning, Mercury and Mars will pair up in the morning sky. Venus glows brilliantly before dawn and can help guide you to the close duo. Mercury pops above the horizon about 45 minutes before sunrise and lies low in the sky. Under clear skies, Mars might be glimpsed very close to Mercury. Mars, a mere magnitude +1.3, is a very difficult catch near Mercury even with binoculars or a telescope. Binoculars may help you find them in the morning twilight. Start looking about 30 to 40 minutes before sunrise. You’ll need an unobstructed view of the southeastern horizon for this close planetary pairing. Mercury will be shining at -0.2 magnitude and Mars will be dimmer at +1.3 magnitude. They’ll be about 1/2 of the diameter of a full Moon apart that morning. They will be closest, only 0.2 degrees apart, at 11am EST. This is the first of six close encounters Mars will have with each of the planets, as viewed from Earth, in our solar system over the next seven months.
Mercury, at magnitude –0.2, remains 12° lower left of bright Venus low in the dawn this week. The time window is becoming very narrow between when Mercury rises and dawn grows too bright for it.
Venus, at magnitude –4.0, shines in the southeast during dawn, getting lower every week. Look for orange Antares, magnitude +1.0, upper right of Venus.
Jupiter, at magnitude –2.4 in the constellation of Aries, is the bright white dot very high in the south at nightfall, and lower in the southwest later. It sets around midnight. In a telescope Jupiter has shrunk to only 40 arcseconds wide.
Saturn, at magnitude +1.0 in the constellation of Aquarius, sinks lower in the west-southwest during and after dusk. It sets around 7pm.
The biggest well-known asterism is the Winter Hexagon. It now fills the sky toward the east and south these evenings. Start with brilliant Sirius at its bottom. Going clockwise from there, march up through Procyon, Pollux and Castor, Menkalinan and Capella on high, over and down to Aldebaran, then to Rigel in Orion’s foot, and back to Sirius. Betelgeuse shines inside the Hexagon, off center. The Hexagon is somewhat distended. But if you draw a line through its middle from Capella down to Sirius, the “Hexagon” is symmetric with respect to that long axis.