This is Dudley Observatory’s Skywatch Line for Friday, March 3, through Sunday, March 5, written by Sam Salem.
On Friday, Sun rises at 6:28am and sets at 5:48pm; the 30% illuminated Waxing Crescent Moon rises at 9:33am, reaching transit altitude of 60 degrees south at 4:34pm, and sets at 11:44pm. The Moon reaches first-quarter phase on Sunday at 6:32am. On Saturday, the dark limb of the almost first-quarter Moon occults Aldebaran for viewers in most of the United States, Mexico, and Central America. That evening, the Moon visits the Hyades cluster in Taurus Constellation and moves south of Aldebaran, the constellation’s brightest star. The Moon will be 0.2 degrees east of Aldebaran shortly after 11pm. Aldebaran disappears around 11:10pm and reappears around 11:30pm. On its way through the Hyades, the dark limb of the Moon will cover several moderately bright stars. As the Moon slowly shifts eastward, the hills and valleys along the northern edge of the lunar disk will cause Aldebaran to blink off and on multiple times. Few observers across southern Canada and the northern United States will get to witness this rare “grazing” occultation. The International Occultation Timing Association has set up a special web page for the Aldebaran graze, with Google Maps of the northern graze line from Connecticut across the Great Lakes to Vancouver. http://occultations.org/aldebaran/2017march/
Venus at magnitude -4.8 shines shortly after sunset. Almost 13 degrees above and to the left of Venus is Mars, glowing at magnitude 1.3. Jupiter at magnitude -2.3 rises in the east above Spica in Virgo. It climbs to the meridian around 3:00am. Saturn at magnitude 0.5 is located in the southern Ophiuchus, between constellations Scorpius and Sagittarius, and rises shortly after 2:30am.
On Sunday night, the Moon resides inside the Winter Circle, a large star configuration made of seven brilliant stars. In the Northern Hemisphere, we see the Winter Circle fill up much of the southern sky at nightfall. The Winter Circle, or the Winter Hexagon, is a pattern of stars that’s easy to recognize. At nightfall, look high up for the bright star Capella. This star marks the top of the Winter Circle. As darkness falls, look for the constellation Orion, the Hunter. Draw a line downward through Orion’s Belt to find Sirius, the brightest star in the night sky. Sirius marks the bottom, or the southern tip, of the Winter Circle.
Spot Capella, the brightest star in constellation Auriga, with unaided eye before sunset this weekend. Capella reaches transit altitude of 87 degrees north, almost 40 minutes after sunset, at 6:26pm on Friday.