Skywatch Line for Wednesday and Thursday, June 12 and 13, 2024, written by Alan French
This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, June 12 and 13, 2024, written by Alan French.
The Sun rises at 5:16 A.M. on Wednesday and sets at 8:34 P.M. On Thursday it rises at 5:16 and sets at 8:35. This Thursday has just under 5 minutes more daylight than last Thursday.
The Moon reached new last Thursday and will reach first quarter early Friday morning, so a fat crescent Moon will dominate the early evening skies. At 9:00 P.M. Wednesday, with the sky bright with evening twilight, the Moon will be 41 degrees above the west southwestern horizon. It will be 39% in sunlight. By 10:00 P.M. it will be lower in the sky and farther toward the west. The Moon is in Leo, the Lion, and the darker skies will allow you to spot Regulus, the star marking the Lion’s heart, 10 degrees to the lower right of the Moon.
On Thursday at 9 P.M. the Moon, its visible face now 48% sunlit, will be 43 degrees high toward the southwest. Either night would be fine for exploring the Moon with a telescope or binoculars. Some planetarium apps allow users to zoom in on a current view of the Moon and identify features. There are also apps dedicated to exploring the Moon.
There are passes of Tiangong, the Chinese space station, over our area on both nights. The pass Wednesday is later, under darker skies, and the space station will move into the Earth’s shadow and fade from view when well above the horizon. The pass Thursday night is earlier and under twilight skies. There are now three people working and living on Tiangong.
All satellites are fainter and harder to see when visible low in the sky, and become brighter and easier to spot as they move higher. They also move faster when higher in the sky, since less of their motion is toward us.
On Wednesday look for Tiangong coming up from the western horizon, headed southeast at 10:10 P.M. At 10:11 it will be passing below Regulus. By 10:11:30 (HH:MM:SS) the station will be passing below the Moon. Just before 10:13 it will pass above Spica and at 10:13, shining at magnitude -1.7, well below Arcturus. As Tiangong approaches the southeast it will enter the Earth’s shadow and fade from view when still 32 degrees above the horizon. How far can you follow it once it starts fading?
Look for Thursday’s Tiangong pass, which will be higher and brighter, beginning at 9:10 P.M low in the west. At 9:11:33 the station will pass close to Regulus and just after 9:12 will pass above the Moon. Its journey will then take it below Arcturus just before 9:13. Then it will head down toward the east southeastern horizon. It will move into the Earth’s shadow when 8 degrees above the horizon but may vanish from sight before then, depending on atmospheric transparency. At its highest and brightest it will reach magnitude -1.9.