This is the Dudley Observatory Skywatch Line for Wednesday, May 13th, and Thursday, May 14th, written by Louis Suarato.
The 60% illuminated, waning gibbous Moon sets at 11:11 a.m. Wednesday. The Last Quarter Moon occurs at 10:03 a.m. Thursday. Venus is closer to the horizon after sunset each night as it approaches the Sun. Our neighboring planet is now 12% illuminated, and shines at magnitude -4.60. Venus becomes stationary, meaning it is also the end of Venus’ northeasterly movement against background stars. It will begin to move in a southwesterly direction.
Jupiter also becomes stationary, and rises 45 minutes past midnight. Jupiter’s moons put on a show overnight into Thursday morning. As Jupiter is rising, its largest moon, Ganymede, will be crossing the face of the planet. By 2 a.m., Ganymede will be ¾ across the planet, with its shadow trailing. At 1:58 a.m., Europa begins its transit, and 11 minutes later, Io is eclipsed by the gas giant. Ganymede’s transit ends at 2:45 a.m., and Europa’s transit will end at 4:45. Saturn rises at 1:00 a.m. Thursday. The Moon rises in the constellation Capricornus at 2:11 a.m., followed by Mars 17 minutes later. Friday morning, the Moon will be 4 degrees below Mars.
Surprisingly, Comet C/2019 Y4 (ATLAS) has begun to brighten again after breaking up into more than 30 pieces. Look for Comet Atlas after 9 p.m. very close to the Double Cluster about 20 degrees above the northwestern horizon. Comet Atlas makes its closest approach to the Sun on May 23rd. Comet C/2020 F8 (SWAN) is growing a long tail. Recent photographs show its tail about 8 degrees long. Now shining at magnitude 5.5, Comet Swan is expected to brighten further when it is low in the Northern Hemisphere sky in mid-May. Look low over the east-northeastern horizon for the comet until then.
There will be an extremely bright International Space Station pass over our region beginning at 4:55 Thursday morning. Look for the ISS to emerge out of the west-northwest, shining at magnitude -3.8. The ISS will pass through the constellation Bootes, over its brightest star, Arcturus, before heading toward Hercules. The Space Station will continue on to Aquila, sailing very close to its brightest star, Altair. The ISS will then fly by Jupiter and Saturn before splitting the Moon and Mars, and disappearing into the southeastern horizon.