Skywatch Line for Friday, July 12, through Sunday, July 14, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, July 12, through Sunday, July 14, written by Sam Salem.
On Friday, Sun rises at 5:28am and sets at 8:33pm; Moon rises at 12:07pm and sets at 11:56pm.
The Moon will reach apogee, its farthest distance from Earth in its elliptical orbit around Earth, on Friday, when it’s 251,258 miles away.
On the Saturday evening, the 1st quarter Moon will hang close to the bright star Spica in the constellation of Virgo the Maiden. They’ll rise before sunset and be visible until around midnight. In North America we will see the Moon pass in front of, or occult, Spica on Saturday. The 1st-magnitude star will vanish behind the Moon’s dark limb, then will reappear from behind the bright limb up to an hour or more later. Rarely do we see the Moon occult such a bright star. For the East Coast the Moon will be getting low in the western sky. In a dark sky your naked eyes might be enough to catch the star disappearance, depending on your vision and the clarity of the air.
The first quarter moon rises around noon and sets around midnight. Watch for it high in the sky at sundown.
Mercury is not an easy catch even at magnitude –0.2. Look for it quite low in the west-northwest during bright evening twilight. Use binoculars.
Venus, at -3.9 magnitude, is even deeper in evening twilight, about 13° to Mercury’s lower right (roughly a fist at arm’s length). Try about 20 minutes after sunset and use binoculars.
Mars, at magnitude +0.9 in Aries nearing Taurus, glows modestly in the eastern sky before and during early dawn. Mars sits upper right of bright Jupiter by 1½ or 2 fists. In a telescope Mars is just a tiny fuzz blob 5.5 arcseconds wide.
Jupiter, at magnitude –2.0 in the constellation of Taurus, glares low in the east-northeast before and during early dawn.
Saturn, at magnitude 1.1 near the Aquarius-Pisces border, rises around midnight and shines high in the southeast before dawn. The Great Square of Pegasus is two fists upper left of it. Fomalhaut, the brightest star in the southern constellation of Piscis Austrinus the Southern Fish, sparkles two fists lower right of Saturn. Fomalhaut is used in navigation because of its conspicuous place in a sky region lacking bright stars.
Uranus, magnitude 5.8, lies between Jupiter and Mars. It’s still low in the dawn for something so faint. If you’ve never found Uranus before, Monday morning could be your chance using Mars as a guide. The red planet will lie close to the planet Uranus. They will be about a half degree apart or roughly the width of the full Moon. Brighter Jupiter, the orangish star Aldebaran and the Pleiades star cluster will complete the scene. While it is possible to see Uranus without optical aid, binoculars will help catch its dim blue-green light.
Neptune, at magnitude 7.9 in the constellation of Pisces, is about 10° left of Saturn before dawn begins. Use large binoculars or a telescope and a detailed finder chart showing Neptune’s current location among the similar-looking faint stars around it.