Catch the planets in the evening sky, starting with Mercury, then Mars and Saturn. A meteor shower coincides with the new moon.
Finding Mercury in the Sky
May is the best time to spot Mercury all year. It appears in the west after the sun sets and the sky darkens. It starts off the month shining at about magnitude -1 but dims quickly to magnitude zero by May 10 and to +1 a little over a week later. Mercury, being the closest planet to the sun, never strays far from the sun from our vantage point on Earth. When it reaches its maximum separation from the sun in our sky it is called greatest elongation. That moment occurs on May 13 when it reaches a distance of 22 degrees from the sun. Mercury will sink back toward the sun by the end of the month and by June, Jupiter will replace Mercury in the evening sky.
Mars Meets the Beehive Cluster
Mars has been a good target all year. In May it is high in the west after sunset. The Red Planet appears in the constellation Gemini beside the stars Castor and Pollux. You can tell which of those brighter three points of light is Mars by its reddish color. Mars is on the move in May though, and it will soon leave Gemini for the constellation Cancer, where it will rendezvous with the Beehive Cluster. But first it meets up with the moon on May 9 and 10. The Beehive Cluster lies at the center of Cancer. This grouping of stars can be seen without binoculars from the suburbs. Mars will take most of a week to pass by the cluster, starting around May 20 and leaving on May 24. Improve your view by using a pair of binoculars or a telescope.
Saturn and Regulus Get Their Closest
The Ringed Planet has been near the star Regulus in Leo the Lion for months. Saturn is the slightly brighter of the two at magnitude 0.5. It also sports a yellowish hue. Regulus is magnitude 1.3. Regulus normally marks the dot at the bottom of Leo's backward question mark shape, but with Saturn nearby it seems to have a double dot. The pair comes within two degrees of each other on May 11. On the next evening a half-lit moon enters the picture. Saturn's rings continue to close up from our point of view, making them more difficult to see in amateur telescopes.
The Eta Aquarid Meteor Shower
The Eta Aquarid meteor shower is one of two annual showers that come from debris left behind by Halley's Comet. The peak of this shower should occur between May 4 and 6, with a wider but less active display from May 1 to 8. The Zenithal Hourly Rate during the peak is 45 meteors. Because new moon occurs on May 5, a dark sky will make it easier to see all the meteors, whether bright or faint.
The Moon in May
The moon pairs up with a number of planets during the evening hours in May, as described above. The full moon this month is the smallest one of the year, occurring as the moon is near apogee. Apogee is the point in an object's orbit when it is farthest from Earth. The full moon occurs on May 19 at 10:11 pm EDT and the moon reaches apogee on May 20.
