Skywatch Line for Friday, March 20, through Sunday, March 22, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, March 20, through Sunday, March 22, written by Sam Salem.
On Friday, Sun rises at 6:58am and sets at 7:08pm; Moon rises at 7:28am and sets at 9:28pm.
The vernal equinox occurs on Friday at 10:46am, bringing spring to the Northern Hemisphere.
The Moon reaches perigee, its closest point to us in its elliptical orbit around Earth, on Sunday. It’ll be 227,954 miles away from Earth.
On Friday evening, watch the waxing crescent Moon hanging low in the western sky after sunset. The Moon floats in the sky over the -3.9-magnitude planet, Venus. In the early evening, the eerily thin Moon hangs about 8° above Venus, low in the west in the fading twilight. Venus stands just under 10° above the western horizon at this time, located in southeastern Pisces. The two-day-old thin silver Moon’s eastern limb is just starting to experience sunrise, while the rest of the nearside remains in darkness. You might see some of the darkened surface because of the sunlight bouncing off Earth, a phenomenon called earthshine.
Venus through a telescope is a bright disk is nearly fully lit (95 percent) and stretches 10” across. The best time to view it is in early twilight while the background sky is still bright. Venus sets around 8:40pm.
On Sunday evening, the waxing crescent Moon lies near the Pleiades star cluster in the constellation Taurus the Bull, also known as the 7 Sisters. Taurus’ brightest star, Aldebaran sits nearby. They’ll set around midnight. After dark, spot the Pleiades about 5° upper left of the waxing crescent Moon.
Use a small telescope or binoculars on Sunday evening to see the two gray lunar maria “seas” come into sunlight. See the round Mare Crisium near the lunar limb, and Mare Fecunditatis, more irregular, farther in from the limb, and more centered in the crescent’s arc.
Jupiter is bright nearly overhead as you face south. Jupiter shines at magnitude –2.3, making it the brightest point in the night sky. It soon shifts to the very high southwest, then moves lower as the evening grows late. It sets around 3 am. In a telescope Jupiter is 41 arcseconds wide. It’s shrinking and fading as Earth pulls farther ahead of it in our faster orbit around the Sun.
Sirius, the brightest star in the night sky, shines in the south-southwest direction. To its lower left, about the size of a fist, lies the triangle of Aludra, Wezen, and Adhara, arranged from left to right. These stars form the tail, rear end, and hind foot of the constellation Canis Major, respectively. Alternatively, they can be seen as the handle and the lower end of the Meat Cleaver. Just to the left or upper left of the triangle, forming a narrow arc that’s slightly wider than the triangle, are the three uppermost stars
of the constellation Puppis. These stars are the poop deck of the ancient constellation Argo Navis, the ship of Jason and the Argonauts. Notably, these three stars are the only stars of Argo that are visible to the naked eye from mid-northern latitudes. Just 1.5 degrees above the middle of these three stars, binoculars on a clear night will reveal the small 6th-magnitude open cluster M93. This cluster is elongated in a northeast-southwest direction.