Skywatch Line for Wednesday and Thursday, September 25 and 26, 2024, written by Alan French
This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday,
September 25 and 26, 2024, written by Alan French.
The Sun rises at 6:46 A.M. on Wednesday and sets at 6:39 P.M. On Thursday it rises at 6:46 and sets at 6:44. This Thursday has 19 minutes, 06 seconds less daylight than last Thursday.
The Moon reached last quarter on Tuesday and is now headed toward new. On Wednesday a pale, crescent Moon is visible in the daytime sky. At 9 A.M. it is high in the southwest, 66 degrees high and just over 42% in sunlight. At noon it is 35 degrees high in the west, and it sets in the northwest at 3:42 P.M. The Moon does not rise again until 13 minutes
after midnight, leaving Wednesday night’s sky before midnight dark and moonless.
At 5:30 A.M. Thursday morning the 33% illuminated crescent Moon is high toward the east, with Mars and Jupiter above it. Mars will be 12 degrees to the Moon’s upper right, and Jupiter 33 degrees away and farther to the upper right. Bright Jupiter is high in the sky, 69 degrees above the horizon.
The Moon spends even more time in the daytime sky on Thursday. At 9 A.M. it is 71 degrees above the south southwestern horizon and, against the bright blue sky, appears as a pale, 32% sunlit crescent. Lost in the bright blue sky, the crescent Moon can sometimes be difficult to spot. At noon you will find it 44 degrees above the western horizon. It will set at 4:22 P.M. in the west, and not rise again until 1:21 A.M. Friday. The Moon will reach new next Wednesday, October 2.
Jupiter is now high in the predawn sky. Views through a telescope, when the planet is high in the sky, are more likely to appear steady and undistorted and show a lot of detail. Our Earth loses heat at night, and this distorts our planetary views. By dawn the cooling has slowed, so there is usually less distortion. (There is also often less distortion
around dusk, when there is a pause between heating and cooling.)
On Thursday Jupiter will be due south and highest at 5:54 A.M. when it will be 70 degrees above the horizon. At 5:00 A.M. the planet will already be 67 degrees high and the skies will still be dark. On Friday morning Jupiter will be due south and highest at 5:50 A.M. and 67 degrees high under dark skies at 5: A.M.
There is a nice pass of the International Space Station across the region’s northern sky on Wednesday night. Look for the ISS low in the northwest at 8:12 P.M. At 8:13 it will be approaching the bottom of the Big Dipper’s bowl, by 8:14 it will be moving through the bowl. By 8:15 it will pass below Polaris, the North Star, and by 8:16 just below the
familiar W of stars marking Cassiopeia, the Queen. Just after passing below Cassiopeia, the space station will enter the Earth’s shadow and fade from view.