The Sons of Perseus
09 August 2012
There is quite a lot going on this Saturday night/Sunday morning; the conjunction of Spica, Saturn and Mars continues as a celestial triangle gradually becomes a line of 1st-Magnitude “stars” in the evening sky, a major meteor shower reaches full intensity (its “peak”), and the Moon plays ‘tag’ with two bright planets. Plenty of excitement for the evening observer and early-riser to enjoy, so lets get started!
First, an update on the ongoing conjunction of Saturn, Spica and Mars. Over the past week Mars has moved eastward and will be passing between stationary Spica and slow-moving Saturn during the next week. Even now, as it draws “nearer” the ringed planet and distant star, Mars has moved close enough that you can easily view all three simultaneously through binoculars. Compare the members of the triad members’ relative brightness and hue—what a terrific contrast of colors!
Keep an eye on these three—the show isn’t over.
Now, for the Main Event. On Sunday morning the Perseid meteor shower will reach it’s peak for this year; over the past few weeks we’ve been seeing more and more of these “shooting stars”, and the time has come at last for the grand finale. The Perseids (the name is Greek for “the sons of Perseus”, a reference to the mythological hero) have been observed for at least 2000 years, and are one of the year’s most impressive displays of celestial fireworks, with up to 80 bright meteors (and hundreds of dimmer ones) visible to the naked eye per hour at peak.
The best time to observe meteors is in the three to four hours before dawn on Sunday, when Earth’s rotation brings the shower’s “radiant” (the area of the sky from which the meteors appear to move outward from) up in the eastern sky. As the name suggests, the Perseid shower’s radiant is located in the constellation Perseus (see the map below), but don’t concentrate your viewing on that spot alone. Pick an area with as few lights, buildings or trees as possible, lean back so you can comfortably watch your chosen “sector” (I usually use an air mattress or lawn recliner chair), have a thermos handy and bug-repellent ready, and enjoy the show.
The closing act for the night will be the view to the east an hour or two before sunrise; the waning crescent Moon, 1st-Magnitude star Aldebaran, Jupiter and Venus will be putting on a lovely display. Jupiter and Aldebaran (alpha Tauri) will be above the Moon, and Venus (brightest thing in the sky after the Moon) will be low above the horizon.
I hope you all can get out for at least part of Saturday night/Sunday morning’s sky show—you don’t need to put in an all-nighter (though I probably will!) to observe four planets, the Moon and one of the most amazing meteor showers of the year. Let me know what you do see of the night’s attractions by writing to my shore-side email (email@example.com) , and above all—be safe out there in the dark!
USNS Joshua Humphreys