This Week’s Sky at a Glance, 2021 July 31 – August 7
~by Curt Nason
After twilight the bright star Altair is halfway up in the southeastern sky, forming the lower peak of the Summer Triangle with Vega and Deneb. It is flanked by two somewhat dimmer stars, Tarazed and Alshain, and the trio forms the head of Aquila the Eagle. The eagle’s body and tail stretch southward, while the wings reach forward to propel it up the Milky Way. In Greek mythology the eagle was the pet of Zeus and the bearer of his deadly thunderbolts. In Chinese mythology Tchi-Niu (Lyra) was a princess and royal weaver, and Kien-Niou (Aquila) tended the king’s cows. The two fell in love and were married but they subsequently neglected their chores. Angered, the king placed the herder on the opposite side of the river, represented by the Milky Way. On the seventh day of the seventh month all of the magpies in the country form a bridge to allow the lovers to be together for one day.
Following a string of stars beyond the eagle’s tail, over the constellation border into Scutum the Shield, a binocular search will pick up a smudge of light which is a cluster of stars called M11 or the Wild Duck Cluster. From the eagle’s head toward Cygnus or Lyra is a tiny constellation called Sagitta the Arrow. Look to the upper right of the arrow’s fletching with binoculars to see a popular asterism of about ten stars. Although it is upside down you will recognize the Coathanger Cluster, also known as Collinder 399 or Brocchi’s Cluster.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 6:00 am and sunset will occur at 8:49 pm, giving 14 hours, 49 minutes of daylight (6:07 am and 8:52 pm in Saint John). Next Saturday the Sun will rise at 6:09 am and set at 8:40 pm, giving 14 hours, 31 minutes of daylight (6:16 am and 8:43 pm in Saint John).
The Moon is at third quarter this Saturday, rising just after midnight and setting 14 hours later. Saturn is at opposition on Monday, leading Jupiter across the sky by 50 minutes. Both will be popular evening telescope and binocular targets for the rest of the year. Telescope users can catch Jupiter’s Red Spot around 11:30 pm Monday. Venus sets around 10:15 pm this weekend, passing the torch to Jupiter low in the southeast. Mars sets an hour after sunset but it is an increasingly difficult target in binoculars. Mercury reaches superior conjunction on Sunday, moving into the evening sky later in the week.
Questions? Contact Curt Nason.