This is the Skywatch Line for Monday and Tuesday, May ninth and tenth.
The Sun sets at 8:05 PM; night falls at 10:20. Dawn breaks at 3:41 AM and ends with the Sun rising at 5:37.
The Monday twilight sky reveals the four-day-old Moon moderately high in the western sky. In Orion, the Moon appears about fourteen percent illuminated and blazes at minus 6.5 magnitude. Tuesday finds the Moon in Gemini, brighter and about 23 percent illuminated. Monday’s Moon sets at 11:17 PM; Wednesday finds it setting after Midnight.
Jupiter is the other beacon in tonight’s sky. Also up by sunset, Jupiter still appears beneath Leo’s belly. While binoculars permit viewers to see several of Jupiter’s 67 moons, telescopic explorers can on see two events. On Tuesday, the Great Red Spot, a giant storm on Jupiter, appears about 9 PM; twenty-seven minutes later, they can witness the Jovian moon Europa depart the planet’s face.
Mars, Saturn and the star Antares rise at nightfall. They are very low on the horizon. By Midnight, they are high enough for observation. Mars rises first at 9:20 PM; Saturn follows at 9:55. Red Planet Mars shines minus 1.8 magnitude and appears twenty degrees high; Saturn glows at zero magnitude and is about nine degrees from Mars. During the month, Mars travels westward, what astronomers call retrograde, and almost doubles the distance from Saturn. Mars is also stationed about six degrees above the bright star Antares, in Scorpius. Mars also distances itself from the stellar copycat. Mars reaches opposition later this month when it is nearest Earth. Mars, Saturn and Antares form a rough triangle all month. Mars sets during daylight.
Saturn is also worthy of study. Its ring system is a favorite of star parties. But Saturn also possesses a fleet of moons. Astronomers with telescopes can see some of the 62 moons, depending on telescope size. Some apps and reference books provide astronomers with identification. Saturn also sets during daylight. Saturn will celebrate its own opposition next month.
Dawn sees Neptune, in Aquarius, reappear in our skies. Neptune rises at 3 AM, so sky watchers should work quickly to find its blue-green dot before the sky becomes too bright.
The Pleiades, also known as M-45 and the Seven Sisters, are among the oldest known deep sky objects. Ancient Chinese observed the Pleiades during the vernal equinox of 2357 BC. Several books of the Old Testament mention the Pleiades. Ancient Greeks worshiped them. The word “Pleiades,” may derive from the Greek verb “to sail,” since the cluster rose when the sailing season began and set when it ended. The Seven Sisters were nymphs, daughters of Atlas and Pleione. Since most people see six stars, there is a legend of the “Lost Pleiad.” Several stars are mentioned, but none can be definitively identified. The Pleiades are classified as an “open star cluster,” about 367 light years distant. A Japanese car manufacturer uses the Pleiades as their corporate symbol – Subaru.