This Week’s Sky at a Glance, 2025 Apr 12 – Apr 19
This Week’s Sky at a Glance, 2025 Apr 12 – Apr 19
One third of the way from Arcturus to Vega is a pretty semicircle of seven stars that makes up Corona Borealis, the Northern Crown. In the middle of the semicircle is the constellation’s brightest star, called Alphecca (“bright star of the broken ring”). Near the second star on the left (eastern) side of the semicircle is the famous Blaze star, a recurrent nova which is normally too dim for binoculars but it brightens briefly to rival Apphecca about every 80 years. This happened last in 1946 and astronomers expect it will recur any time now.
Some ancient societies regarded Corona Borealis as a begging bowl, and in local aboriginal legend it is the cave from which the bear (the bowl of the Big Dipper) emerges in spring. In Greek mythology it was a crown worn by Bacchus, the god of wine, who lived on the island of Naxos. Theseus, an Athenian prince, went to Crete as part of a group of youth who were to be placed in the labyrinth as food for the Minotaur. With the aid of Ariadne, the daughter of King Minos, Theseus slew the Minotaur and found his way out of the labyrinth. In love with Ariadne, he took her aboard to sail back to Athens. They stopped at Naxos where Bacchus also fell in love with Ariadne, and he made Theseus leave without her. To prove his love and his godliness to the skeptical Ariadne, he tossed the crown into the sky as a symbol of her beauty. Immortality and a lifetime supply of wine, who could pass that up?
This Week in the Solar System
Saturday’s sunrise is at 6:43 and sunset will occur at 8:06, giving 13 hours, 23 minutes of daylight. Next Saturday the Sun will rise at 6:31 and set at 8:15, giving 13 hours, 44 minutes of daylight.
The Moon is full and near Spica this Saturday, and on Wednesday and Thursday it appears west and then east of Antares. Orion and Taurus are setting in late evening with Jupiter following them by about an hour. Telescope users might see Jupiter’s Red Spot around 9 pm Wednesday and 10:30 Friday. Mars crosses the constellation border into Cancer this weekend, heading toward a scenic rendezvous with the Beehive star cluster in early May. Mercury and dimmer Saturn rise together this Saturday morning, about seven degrees directly below Venus.
Tune in to the Sunday Night Astronomy Show at 8 pm on the YouTube channel and Facebook page of Astronomy by the Bay.