Skywatch Line for Wednesday and Thursday, June 19 and 20, 2024, written by Alan French
This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, June 19 and 20, 2024, written by Alan French.
The Sun rises at 5:17 A.M. on Wednesday and sets at 8:37 P.M. On Thursday it also rises at 5:17 and sets at 8:37. This Thursday has just 1 minute, 44 seconds more daylight than last Thursday.
The Moon reached first quarter early last Friday and is headed toward full. On Wednesday the Moon rises at 6:45 P.M. and travels low across the southern sky during the evening. At 9:30 it will be 17 ½ degrees about the south southeastern horizon and 95.6% sunlit. Look for reddish Antares, the brightest star in Scorpius, to the lower left of the Moon, just under 5 degrees away.
Antares is the brightest star in Scorpius and is number 16 on the brightest star list, shining at magnitude 1.06. It is one of four first magnitude stars that lie within five degrees of the ecliptic and can be occulted by the Moon. An occultation will be visible from east China, south Japan, most of Micronesia, Melanesia, and much of Polynesia.
Antares got its name from its color; the Greek name Antares means “The Rival of Mars.” The star marks the heart of the Scorpion.
At 11:13 the Moon will be due south and only 21 degrees above the horizon. The Moon will be slightly closer to Antares, just over four degrees away. Moonset is at 3:35 A.M. Thursday morning.
Thursday night’s Moon rises at 7:55 in the southeast. At 11:30 the 98.8% illuminated Moon will be 18 degrees above the southern horizon. Antares will be 9 degrees to the upper right of the Moon, illustrating how far the Moon has moved eastward against the starry background since Wednesday night. The Moon will set 4:20 A.M. Friday. It will reach full mid-Friday evening.
If you are up in the morning hours you can catch Mars and Jupiter, continuing to rise earlier and slowly moving higher into the pre-dawn morning sky.
At 4:15 A.M. reddish Mars will be 18 degrees above the eastern horizon. Mars now shines at magnitude +1.0 and appears only 5.2 arcseconds in diameter through a telescope. Earth, on its faster, inside orbit, is slowly catching up with Mars. In 3 months, it will appear 7 arcseconds across, and in 6 months 13.1 arcseconds. It will reach opposition, opposite the Sun in our sky, on January 15, when it will appear 14.6 arcseconds across. While this is not a particularly close opposition, the Red Planet will be 72 degrees above the horizon when due south. Looking high in the sky usually provides far steadier telescopic views than those when Mars, or any planet, is low. At the historic, close opposition on August 28, 2003, Mars appeared 25.1 arcseconds in diameter, but was only 31 degrees above our horizon. From the northern hemisphere the ecliptic and planets are highest in the winter months.
Jupiter will be just 3 degrees above the east northeastern horizon but a bright magnitude -2.0. By 4:30 A.M. it will be 5 ½ degrees.