This is the Skywatch Line for Monday and Tuesday, September 2nd (Labor Day) and September 3rd.
The Sun sets at 7:28 PM; night falls at 9:08. Dawn begins at 4:42 AM and ends with the Sun rising at 6:22.
Monday’s Moon joins Jupiter and Saturn as the brightest in the evening sky. The 4-day-old Moon, in Virgo, is about 18% illuminated and blazes with minus 7th magnitude and sets at 9:43 PM. Tuesday’s Moon moves into Libra, appearing fatter and brighter; it sets at 10:14 PM.
This month, Jupiter remains in Ophiuchus, but fades slightly from -2.2 magnitude to minus 2.0; it also seems to be a bit smaller in our eyepieces. Jupiter is quite low in the South, so observe it as soon as possible. The Great Red Spot, a giant storm, is telescopically visible at 9:04 PM on Monday. Also, on Monday, Jupiter’s Moon Europa reappears from behind the planet at 9:07 PM, but is eclipsed by the planet’s shadow only 4 minutes later. Jupiter sets at 11:38 PM.
Saturn follows about 2 hours behind Jupiter. Still in Sagittarius, it shines with zero magnitude and appears about half Jupiter’s size. Saturn dims from minus 2.2 magnitude to 2.0 and shrinks to 17 arc-seconds in size. It is best observed about 9:09 PM and sets at 1:41 AM. Saturn is close to two bright globular star clusters, M-22 and M-28, both can be viewed through binoculars or telescopes.
Dwarf Planet 1Ceres still occupies Scorpius, but it, too, is fading a bit. It now shines with 8th magnitude and looks smaller in our telescopes. It sets at 11 PM.
Neptune still inhabits Aquarius glowing with 7th magnitude and appearing a tiny 2.4 arc-seconds. Already risen, it lies about 14º at nightfall and is highest and best observed at 1:22 AM. Uranus is found in the empty space between Aries and Pisces. Glowing with 5th magnitude, is naked-eye visible under dark, rural skies. Its blue color helps identification. Uranus rises at 9:31 PM and is best observed just before Dawn. Finder charts for 1Ceres, Uranus and Neptune can be found in astronomy magazines and websites.
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 pet 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 continue 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.