This Week’s Sky at a Glance, July 28 – August 4 ~by Curt Nason
They say it is the little things that count, and if you are counting constellations there are four little ones lined up in the southeast toward late evening. Start your search with the Summer Triangle, which is composed of the brightest star in each of three constellations: Vega in Lyra the Lyre, Deneb in Cygnus the Swan, and Altair in Aquila the Eagle. Sagitta the Arrow is a distinct shape between Altair and Albireo, which is at the head of Cygnus. The arrow, poisoned with the blood of the Hydra, is one of those shot by Hercules to kill the Stymphalian birds as his sixth Labour.
Between Sagitta and Albireo is obscure Vulpecula the Fox, which at one time was two constellations called the Little Fox and the Goose. Vulpecula is known best for having the binocular object M27, the Dumbbell Nebula, within its borders. Below Sagitta is the eye-catching Delphinus the Dolphin, seen leaping out of the watery constellations that hug the horizon below. The dolphin was given its place of honour in the sky by Poseidon for convincing beautiful Amphitrite to be his wife. Below Delphinus and just off the snout of Pegasus the Flying Horse is Equuleus the Little Horse, the second smallest of the 88 constellations. Perhaps representing the foal Celeris, an offspring or brother of Pegasus, it was one of the 48 constellations included in Claudius Ptolemy’s second century map of the sky.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 5:56 am and sunset will occur at 8:53 pm, giving 14 hours, 57 minutes of daylight (6:04 am and 8:56 pm in Saint John). Next Saturday the Sun will rise at 6:04 am and set at 8:44 pm, giving 14 hours, 40 minutes of daylight (6:12 am and 8:47 pm in Saint John).
The full Puny Moon occurs on Friday, July 28, and it is at third quarter on Saturday, August 4. Mars is at opposition on July 27 and closest to Earth on July 31. Normally, the outer planets are closest at opposition but Mars has a more elongated orbit than the others. Its continued sunward motion brings it about 100,000 km closer after opposition before Earth pulls farther ahead in orbit. Mars looks brilliant to the naked eye but a global dust storm still obscures much of its telescopic treasures. Venus shows its nearly half-lit phase in a telescope, best seen in twilight, while Jupiter and its moons and Saturn’s rings more than make up for the Martian disappointment. The South Delta Aquariid meteor shower peaks this Saturday morning, a harbinger of the more prolific Perseid shower in a few weeks.
The Saint John Astronomy Club meets in the Rockwood Park Interpretation Centre on August 4 at 7 pm. All are welcome.
Questions? Contact Curt Nason.