This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday August 30th, and 31st, written by Joe Slomka.
The Sun sets at 7:33 PM; night falls at 9:14. Dawn begins at 4:38 AM and ends with the Sun rising at 6:19.
The Moon, in Taurus, reached Last Quarter on Monday; it rises at 11:46 PM in the Northeast, 29 arc-minutes large, 44% illuminated and sets at 3:35 PM Tuesday. The Moon doesn’t rise again until 12:27 AM Wednesday.
Western Virgo houses Venus and Mercury. Mercury sets first at 8:17 PM and appears 5 arc-seconds in size. Venus sets next at 8:55 PM, blazing with 4th magnitude, a large 15 arc-seconds and 73% lit. Both planets are very low and require an unobstructed view. Venus is 10° high while Mercury is only 3° above the horizon and 16° to Venus’ lower right.
Capricornus contains Saturn and Jupiter in the darkening southeast. Saturn appears first already up. By 8 PM, it is 15° high, shining with zero magnitude and is highest at 11 PM. Jupiter trails Saturn by 17° to Saturn’s left. The Gas Giant flashes with minus 2nd magnitude, a large 49 arc-seconds and highest at 12:14 AM. Both planets are in retro-grade, which means they both seem to temporarily back up westward.
Neptune, in Aquarius, is next, rising at 8:06 PM, glowing with 7th magnitude, a tiny 2 arc-seconds. Neptune is 10° high by 9 PM, 20° at 10 PM and highest at 1:53 AM. Neptune is nearing Opposition, which means almost ideal position for viewing. Uranus is last to rise, in Aries, at 10:05 PM, glimmering with 5th magnitude, 20° high at Midnight and is highest at 5:09 AM. By 1 AM, Uranus is 33° to the Moon’s upper right. At 5th magnitude, Uranus is visible through binoculars all night, but a sky chart is necessary to find it amid similar looking stars.
At 1 AM on Tuesday, Saturn, Jupiter, Neptune, Uranus and the Moon are arrayed in a straight line – the Ecliptic where the Sun, Moon and planets travel.
While looking at the Ecliptic, turn your binoculars to Mira, in Cetus. This star dims from third magnitude to 9th in a period of 333 days. The star reached maximum earlier in August and lies to the lower left of Uranus. Star charts help find it.
Ancient peoples saw the sky as the realm of the gods and told stories about their constellations. By midnight, all the constellations that make up the Andromeda story are visible. We previously mentioned Cassiopeia and Cepheus. Cassiopeia angered some gods and Ethiopia was subjected to severe calamities. An oracle told Cepheus that disasters would end if he chained Andromeda to a seaside rock to be eaten by the sea monster Cetus. Perseus was returning from a mission to kill the Medusa, a woman so hideous that her visage turned people to stone. One version of the myth has Perseus returning by his horse Pegasus. He hears Andromeda’s cry for help. The parents, nearby, promise her hand in marriage if he saves her. He kills Cetus and frees Andromeda. “W” shaped Cassiopeia and Cepheus, shaped like a stick drawing of a house, are visible overhead. Pegasus, the flying horse, is a Great Square high in the eastern sky, flying upside down; his neck begins at the lower right star of the square. Andromeda’s chains flow from the upper left star in the square and continues eastward. The famous Andromeda Galaxy lies above the upper chain and is visible to naked eyes in rural skies. Perseus appears to the east of Pegasus, resembling a stick drawing of a man with one long and one short leg. The brightest star in the short leg is Algol, the “Demon Star.” It represents the evil eye of the Medusa. Cetus lies beneath Pegasus and Pisces. It is a dim constellation low on the horizon for our latitude.