This is the Dudley Observatory Skywatch Line for Wednesday, July 29th, and Thursday, July 30th, written by Louis Suarato.
The 74% illuminated, waxing Gibbous Moon rises at 4:07 p.m., Wednesday. Look for Scorpius’ brightest star, Antares, 6 degrees below the Moon. Antares, also known as Alpha Scorpii, means “rival of Mars” because of its reddish hue. This red supergiant is a variable star, which on average is the 15th brightest star in the sky, and one of the largest visible to the naked eye. Antares is estimated to be 12 times the size of the Sun. Antares is about 11 million years old and 550 light-years from Earth. While the Moon is high over the southern horizon, Saturn and Jupiter can be seen over the southeastern horizon. Mars rises at 11:17 p.m. in Pisces. Venus joins the three outer planets at 2:33 a.m., in Taurus, to the lower left of its brightest star, Aldebaran.
Comet C/2020 F3 (NEOWISE) is fading, but can still be seen using a visual aid such as binoculars. At 9:30 p.m., Wednesday, Comet NEOWISE will be about 32 degrees above the west-northwestern horizon. It is estimated to be 3.0 magnitude. It is exiting our solar system at 144,000 miles per hour, about 3 degrees per night. This comet is expected to be seen in our sky until October, but will fade to 13th magnitude. Thursday night, when Comet NEOWISE is 24 degrees above the horizon, the international Space Station will fly very close by the comet. Beginning at 10:11 p.m., the -3.8 magnitude ISS will emerge from the horizon below the comet. At 10:12 p.m., the ISS will sail by Comet NEOWISE. A long exposure should show the trail of the ISS and the comet. The ISS continues toward Bootës and heads toward the Summer Beehive Cluster in Ophiuchus (not to be confused with M44, the Beehive Cluster in Cancer) before disappearing into Earth’s shadow. Comet NEOWISE will set about 15 minutes after midnight.