Skywatch Line for Wednesday and Thursday, October 4 and 5, 2023

This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, October 4 and 5, written by Alan French.

The Sun rises at 6:56 A.M. on Wednesday and sets at 6:32 P.M. On Thursday it rises at 6:57 and sets at 6:30. This Thursday has just over 20 minutes less daylight than last Thursday.

The Moon is now approaching last quarter and rises late in the evening. The Moon, 65% illuminated, rises at 9:40 P.M. Wednesday night. On Thursday it rises at 10:32 P.M. and will be just over half sunlit. It
reaches last quarter, having completed three-quarters of its journey around Earth since the last new Moon, Friday morning.

If you are up around 6:00 A.M. look for the Moon high toward the south, almost overhead.

Venus continues its dazzling display as the Morning Star, shining brightly almost 20 degrees above the eastern horizon at 5:00 A.M. Regulus, the brightest star in Leo, the Lion, lies 4 ½ degrees to then lower left of Venus. Regulus shines at magnitude 1.4, while Venus is magnitude -4.5. Venus will remain prominent in the morning sky through the end of the year.

There is a nice pass of Tiangong, the Chinese space station, high across the southern sky against dark skies on Thursday night. We see satellites because they are up in sunlight while we are down in the Earth’s shadow. During this pass the space station will move into the Earth’s shadow and fade from view.

Look for Tiangong coming up from the western horizon at 7:49 P.M. Thursday. When satellites are low in the sky, they are moving mostly toward us, so they move slowly against the stars, and their brightness
is reduced by the thick atmosphere the light passes through, so they can be hard to spot at first. As they move higher, they brighten and their motion is more obvious.

By 7:50 the Chinese space station will be as high as bright Arcturus, the luminary of Boötes, 17 degrees above the horizon and about 14 degrees north of Tiangong. Just before 7:52 Tiangong will be passing
above Ophiuchus and below Hercules. At magnitude -2 and now moving rapidly against the stars it should be easy to spot high above the south southwestern horizon. At 7:52:30 it will be high in the south, 66 degrees above the horizon, and passing above Alair, the brightest star in Aquile, the Eagle.

As the station continues across the southeastern sky it will move into the Earth’s shadow and fade from view, vanishing soon after 7:53 P.M.