This is Dudley Observatory’s Skywatch Line for Friday, May 1, through Sunday, May 3, written by Sam Salem.
On Friday, Sun rises at 5:49am and sets at 7:56pm, the waxing gibbous Moon sets at 2:54am and rises at 12:52pm. Moon is moving through constellation Leo the Lion on Friday. Watch for the Moon when it’ll be near the bright star Regulus, representing the Lion’s Heart. Note where the Moon appears relative to Regulus at nightfall on Friday and then again as darkness falls on Saturday. By Sunday, the Moon will be near a fainter star in Leo, called Denebola. The word “deneb” is Arabic for “tail.” The name Denebola represents the Lion’s Tail.
The dark side of the waxing gibbous Moon points in the Moon’s direction of travel relative to the backdrop stars of the zodiac. The Moon moves one-half degree, or its own diameter, eastward per hour in front of the constellations of the zodiac, or about 13 degrees eastward per day. Sun travels nearly one degree, or two Sun-diameters, eastward per day in front of the constellations of the zodiac. The Sun passes in front of the constellation Leo each year from around August 10 to September 16.
Venus, at magnitude –4.7 in north-central Taurus, is the dazzling white “Evening Star” in the west during and after dusk. Look upper right of Venus for Capella, about two fists at arm’s length away. Roughly the same distance to Venus’s left is Betelgeuse. Much closer to Venus’s upper left, is Beta Tauri, the second-brightest star in the constellation of Taurus, moving down toward it day by day. Venus itself is also sinking lower. On Friday it sets in the northwest about 1½ hours after twilight’s end. In a telescope, Venus has enlarged to about 37 arc-seconds in diameter while waning in phase to be a thick crescent about 28% sunlit. It’s on its way to becoming a dramatically thin crescent low in twilight in late May as it nears conjunction with the Sun.
Mars, Jupiter, and Saturn shine in the southeast before and during early dawn.
Jupiter, the brightest, is on the right. Saturn glows pale yellow 5° to Jupiter’s left.
Mars is ever farther to Saturn’s lower left, moving eastward against the stars away from the other two. Last Saturday morning, Mars was 16° from Saturn; by Saturday Morning this weekend, it retreats to 21° away from it.
The Eta Aquariids have been slowly ramping up since last week and will peak in another few days. It’s not one of the year’s best meteor showers, due to its low-altitude radiant in the Northern Hemisphere and low predicted rate of just 10 meteors per hour at its peak. But with Mars hanging nearby, it’s worth trying to catch a few shooting stars this weekend. Before dawn the next several mornings, meteors from the annual Eta Aquariid meteor shower will be flying, though in the glaring light of the almost-full waxing gibbous Moon. Tuesday morning is expected to showcase the peak number of meteors.
Look high in the west for Pollux and Castor. They’re lined up almost horizontally. These two stars, the heads of the Gemini twins, form the top of the enormous Arch of Spring. To their lower left is Procyon, the left end of the Arch. Farther to their lower right is the other end, formed by Menkalinan, or Beta Aurigae, and then brilliant Capella. The whole asterism sinks in the west through the evening.