Skywatch Line for Friday, February 20, through Sunday, February 22, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, February 20, through Sunday, February 22, written by Sam Salem.
On Friday, Sun rises at 6:45am and sets at 5:33pm; Moon rises at 8:02am and sets at 9:28pm.
On Sunday evening, the waxing crescent Moon shines below the Pleiades after dark.
The Pleiades star cluster, also known as the 7 Sisters, is in the constellation Taurus the Bull. Aldebaran, the brightest star of Taurus sits nearby the Moon.
Locate Mercury in the west in mid-twilight, about 45 minutes after sunset. Mercury is still brighter than its average, though it’s fading to –0.2 on Friday.
Venus sits 7° or 8° down below Mercury. It’s much brighter at magnitude –3.9, but it’s near the horizon obstructions an atmospheric extinction. In a telescope, Venus is a little round disk just 7 arcseconds wide. Being near the horizon it may seem like a super-bright, blobby star.
Jupiter, magnitude –2.6, shines in the middle of the constellation Gemini, shining nearly overhead toward the south in early evening. In a telescope it’s still 45 or 44 arcseconds wide.
Saturn, magnitude +1.1 in the constellation Pisces, is in the west-southwest at dusk. In twilight it’s upper left of brighter Mercury and, after dark, lower left of the Great Square of Pegasus. Saturn sets about an hour after full dark. In a telescope Saturn’s rings are still very thin but gradually opening up. Now they are tilted 2° or 3° to our line of sight. The rings’ thin black shadow on Saturn’s globe is slowly widening too.
On Saturday, Algol should be at its minimum brightness, magnitude 3.4 instead of its usual 2.1, for a couple hours centered on 9:22 pm. Algol, in the constellation Perseus, famously known as the Demon Star, is a prominent eclipsing binary star.
Coma Berenices rises around 7:30pm and is visible all night and into the early-morning hours. It is a home to a lovely star cluster cataloged as Melotte 111 and Collinder 256. This open cluster of stars, also called simply the Coma Star Cluster, lies in the northwest corner of the constellation, near the 4th-magnitude star Gamma (γ) Comae Berenices. The Coma Star Cluster lies adjacent to this golden-hued star. Gamma itself is not part of the cluster, which lies far beyond this single star.
Spanning 4° on the sky, you’ll need a wide field of view to take in the entire cluster at once. Try using binoculars or your telescope’s finder scope. In total, the Coma Star Cluster holds about 40 young suns that are about 400 million years old.
The Big Dipper stands on its handle in the northeast by 9 pm. In the northwest, Cassiopeia also stands on its brighter end at about the same height. Between them is Polaris, about as bright as most of the Big Dipper’s stars.