Skywatch Line for Monday and Tuesday, July 13th and 14th, 2020

This is the Skywatch Line for Monday and Tuesday, July 13th and 14th, written by Joe Slomka.

The Sun sets at 8:32 PM; night falls at 10:41. Dawn begins at 3:22 AM and ends with the Sun rising at 5:50.

Monday’s Moon rises before Dawn and sets in the afternoon. Tuesday, the 38% illuminated Moon rises in Cetus at 1:10 AM and sets at 2:53 PM. Wednesday, the 29% lit Moon rises in Aries at 1:35 AM and sets at 3:55 PM.

The constellation Sagittarius houses Jupiter, Saturn and Pluto. Jupiter rises first at 8:29 PM, glares with minus 2.6 magnitude, appears about 47 arc-seconds in size and is 19° high in the southeastern sky. At 3:13 AM on Tuesday, Jupiter’s moon Io begins its march across the planet’s face. Wednesday at 12:41 AM, Io disappears behind Jupiter and reappears at 2:58 AM. Pluto rises a few minutes later, glimmering with 14th magnitude, appearing one tenth of an arc-second and only 1° from Jupiter.

Saturn is the third to rise at 8:52 PM, shining with zero magnitude and 18 arc-seconds in size. Saturn is preparing for its July 20th opposition, a perfect time to view the planet and its rings. The rings appear about 22° tilted and a large 42 arc-seconds in size.

Neptune, in Aquarius, rises at 11:10 PM on Tuesday. The giant gas planet glows with 8th magnitude and appears about 2 arc-seconds. Mars, 18° away from Neptune, rises in Cetus at 12:05 AM, glows brighter with minus 2nd magnitude and larger with 12 arc-seconds. Uranus, rising in Aries at 1:05 AM, appears about 10° above the Moon, shines with 5th magnitude and 3 arc-seconds. Finally, Venus brings up the rear, rising in Taurus at 2:59 AM, blazes with minus 4th magnitude, appears a large 35 arc-seconds in our instruments and, by 4 AM, appears near Aldebaran, the heart of Scorpius.

As night falls, Scorpius lies due South and obvious to even the casual sky watcher. Scorpius is one of the oldest constellations; its origins lie in the sands of Babylon. Even its star names betray its history.

The Sumerians and Babylonians gave us the Zodiac, as we know it, and gave them names in their languages. When the Greeks occupied the Middle East, they imposed their own names – as did the later Romans. Conquering Arabs also renamed the constellations and stars. Crusaders, who came across Arabic scientific documents, republished all this knowledge, forgotten during the Dark Ages.

Antares is the common name for the red star that marks the Scorpion’s heart. The word Antares means “rival of Ares,” the Greek word for the Roman god, Mars. Indeed, the two do look alike. Of course, Antares is a giant star, while Mars is a small planet. The two stars on either side of Antares were called “Al Niyat,” Arabic for “the Arteries.” Beta, Delta and Nu, in the head, were called Graffias, Deschubba and Jabbah. The stinger’s stars are Shaula and Lesath – again Arabic names. Theta, the star that bends upward to form the tail is called by two Sumerian names: Girtab and Sargas.

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