Skywatch Line for Wednesday and Thursday, May 22 and 23, 2024, written by Alan French
This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, May 22 and 23, 2024, written by Alan French.
The Sun rises at 5:26 A.M. on Wednesday and sets at 8:18 P.M. On Thursday it rises at 5:25 and sets at 8:20. This Thursday has just over 13 more minutes of daylight than last Thursday.
A waxing gibbous Moon is now headed toward full. On Wednesday night the Moon, 99.6% illuminated, rises in the southeast at 7:51 P.M. By 10:00 it will be 16 degrees above the horizon. It will set at 5:02 A.M. Thursday, then 99.8% in sunlight. The Moon will reach full at 9:53 A.M. Thursday. Moonrise Thursday is at 9:01 P.M. It will rise in the southeast and its visible face will be 99.5% in sunlight. Although we could not see the moment of full Moon because it was below our horizon, both Wednesday and Thursday night’s Moon will appear essentially full by eye.
On Thursday the Moon is close to reddish Antares, the brightest star in Scorpius. At 11:00 P.M. the Moon will be 13 degrees high and Antares will be less than ½ degree above the Moon. As time passes, the Moon’s eastward motion against the stars is moving it away from Antares. Earlier, the Moon occulted Antares from parts of the Earth, including southern South America.
There is a bright and interesting pass of the ISS (International Space Station) over our area on Thursday night. It occurs with the Sun almost 20 degrees below the horizon, so all traces of evening twilight are gone, A bright, waxing gibbous Moon will, however, be low in the southeast, on to opposite side of the sky. We see satellites because they are still up in bright sunlight while we are down in the Earth’s shadow and darkness. Because of the passes’ lateness, the Earth’s shadow will be high in the sky, and the ISS will move into the shadow and fade from view when almost overhead.
Look for the ISS coming up from the west northwestern horizon between 10:44 and 10:45 P.M. It will pass just north of Castor, in Gemini, the Twins, just after 10:45. Castor will be 17 degrees high. By 10:47 the space station will be passing under, southwest of, the Big Dipper’s bowl. By then it will be shining at magnitude -3.7. Less than 20 seconds later, still beneath the Big Dipper’s handle, it will move into the Earth’s shadow and fade from view. How far can you follow it before it is too faint to see. Because satellites need to be in sunlight to be seen, we only see them in the hours after sunset and before sunrise.