Skywatch Line for Wednesday and Thursday, July 10 and 11, 2024, written by Alan French
This is Dudley Observatory’s Skywatch Line for Wednesday and Thursday, July 10 and 11, 2024, written by Alan French.
The Sun rises at 5:27 A.M. on Wednesday and sets at 8:34 P.M. On Thursday it rises at 5:28 and sets at 8:34. This Thursday has 7minutes 50 seconds less daylight than last Thursday.
The Moon was new early last Friday evening and is now headed toward first quarter. Look for a waxing crescent Moon toward the west after sunset as twilight fades. At 9:30 P.M. on Wednesday night the Moon will be 19 ½ degrees high and 24% in sunlight. At the same time Thursday, it will be 22 degrees high and 32% in sunlight. Its journey around the Earth is moving it eastward in the night sky and bringing more of its visible face into sunlight. It will reach first quarter this coming Saturday. The coming week will be a good time to explore the Moon with a telescope, or to simply follow its changing position and phase by eye.
Wednesday morning Venus reached perihelion, its closest distance to the Sun, 107.48 million kilometers. None of the planets have truly circular orbits, although they all are close to circular and have low eccentricities, so their distances from the Sun vary some. Venus reached aphelion, its farthest distance from the Sun of 108.94 million kilometers on March 19. Venus’s orbit has the lowest eccentricity of the eight planets.
On Wednesday night there is a fine, bright pass of the International Space Station (ISS) high across our skies. The ISS will pass high across the south southeastern sky and reach magnitude -3.9.
Look for the ISS in the southwest at 9:38 P.M. on Wednesday. It will pass close to Spica, the luminary of Virgo, the Virgin, 25 degrees above the southwestern horizon, at 9:39. At 9:40 the space station, now approaching its brightest, passes well south of Arcturus, in Boötes, and is 50 degrees high.
The ISS next passes through southern Hercules and soon after 9:41 passes through Lyra, the Lyre, high in the east. Passing through Cygnus, the Swan, it then heads down toward the east northeastern horizon. It will disappear sometime after 9:44.
Jupiter and Mars continue their emergence into the morning sky. At 4:00 A.M. both are nicely visible against dark skies in the east. Jupiter, shining brightly at magnitude -2.0 is 12 degrees high. Fainter Mars, at magnitude +1.0 and appearing reddish, is 22 ½ degrees high and 17 degrees to the upper right of Jupiter. If you are up before sunrise, follow them in the coming months.