Skywatch Line for Wednesday, July 10th, and Thursday, July 11th, 2019

This is the Dudley Observatory Skywatch Line for Wednesday, July 10th, and Thursday, July 11th, written by Louis Suarato.

Wednesday night, between 9 p.m. and 9:15 p.m., there will be four planets above the horizon with the 67% illuminated, waxing gibbous Moon. Mars and Mercury will be over the northwestern horizon, but may be too low in the sunset glow to see without binoculars. You’ll find Saturn, a day past opposition, about 10 degrees above the southeastern horizon in Sagittarius, and Jupiter 22 degrees above the south-southeastern horizon, to the left of Scorpius’ brightest star Antares. The Moon will be high in the south-southwestern sky in the constellation Virgo. Thursday night, the Moon moves into Libra and closer to Jupiter. There won’t be any morning planets until Mercury peeks over the eastern horizon in mid-August. Venus won’t reappear until September.

During the summer months, the asterism known as the Big Dipper within the constellation Ursa Major, is located to the west, or the 9 o’clock position, of Polaris, the North Star, after sunset. The Big Dipper then scoops counter-clockwise to the 6 o’clock position before dawn. Ursa Major, also known as The Great Bear, contains seven stars brighter than 3rd magnitude. It’s brightest star is Alioth, which shines at magnitude 1.76. Alioth is the first star on the handle of the Big Dipper from the bowl. Alioth is Arabic for “the leader”. It’s star designation is Epsilon Ursae Majoris, despite Alioth being the brightest star in the constellation. Ursa Major is the oldest of the constellations, whose history dates back to the last Ice Age. It is also the third largest constellation behind Cancer and Virgo. Ursa Major occupies 3.102% of the night sky. This constellation is also the home to several deep sky objects, including spiral galaxies: Bode’s Galaxy (M81), the Cigar Galaxy (M82), and the Pinwheel Galaxy (M101). Ursa Major also hosts the following barred spiral galaxies; M108 and M109. Other Messier objects within Ursa Major are the Owl Nebula (M97), and the double star Winnecke 4 (M40).

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