Skywatch Line for Wednesday and Thursday, January 29 and 30, 2025, written by Alan French
This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, January 29 and 30, 2025, written by Alan French.
The Sun rises at 7:13 A.M. on Wednesday and sets at 5:05 P.M. On Thursday it rises at 7:12 A.M. and sets at 5:06 P.M. Thursday gained 15 minutes, 27 seconds of daylight compared to last Thursday. By the end of January, we will have gained just over 52 minutes of daylight since the end of December.
The Moon is new Wednesday morning at 7:36. The young Moon will be too close to the Sun to be visible Wednesday evening, hidden in bright twilight and setting just 12 minutes after the Sun. A slender, crescent Moon will be visible toward the west southwest soon after sunset on Thursday. At 5:45 P.M. the 2.5% illuminated Moon will be just over 7 degrees above the horizon. By 6:00 P.M. it will be 5 degrees high. A view down to the horizon and skies clear of clouds and haze will aid in spotting this slender crescent. If conditions are less than ideal, try spotting it with binoculars first.
Venus continues to dominate the evening sky. On Wednesday at 6:00 P.M. it is 31 degrees above the horizon, with fainter Saturn 9 degrees below. By Thursday at the same time Venus is only slightly higher, but Saturn is 10 degrees away. Through a telescope we now see about 39% of Venus’ sunlight side. As Venus continues to catch up with Earth and draw closer the fat crescent will slim down and grow larger.
Jupiter is high toward the south by 7:00 P.M. and transits around 7:55. At 7:00 P.M. on Wednesday all four of Jupiter’s bright Galilean moons are to the west of the planet and are easily visible through spotting scopes and astronomical telescopes. In order of their distance from the planet they are Europa, Io, Callisto, and Ganymede. On Thursday night at 7:00 P.M. two moons will be to the west and two to the east. Callisto and Ganymede will be to the west, with Callisto closest to Jupiter. Io and Europa will be to the east, with Io closest. Some astronomical telescopes reverse the view, so note that Io and Europa are farther apart than Callisto and Ganymede.
On Wednesday night look for the International Space Station (ISS) moving up from the northwestern horizon at 6:09 P.M. At first, since the space station is mostly moving toward us, its motion will be slow. It will also be faint. Just after 6:11 P.M. it will pass close to Deneb, the brightest star in Cygnus the Swan, 27 degrees above the northwestern horizon. By then its motion and brightness should make it easy to spot.
The space station’s path will take it high across the north northeastern sky. Just after 6:12 it will pass through the “W” pattern of stars outlining Cassiopeia. It will then pass through Perseus and, at about 6:13:20 (HH:MM:SS) the ISS will pas north of bright Jupiter. It will then move down toward the horizon, passing just north of Orion. It will move into the Earth’s shadow and fade from view when 16 degrees above the east southeastern horizon.