Five good reasons to dine al fresco in May
Updates on a once-in-a-lifetime planetary alignment, as the sun graciously drops out of view.
Plan on eating dinner early the first two weeks in May (or eating outside if you dine late). Then, just after sunset, take advantage of a once-in-a-lifetime naked-eye view of a gathering that began in mid-April of Mercury, Venus, Mars, Saturn, and Jupiter.
Looking west, all but Jupiter will sit in a cluster, visually moving closer in a tight (astronomically speaking) circle some 10 degrees across. (Ten degrees is about the width of your fist held at arm's length.) Jupiter will be the second brightest object, after Venus, some 30 degrees above the main cluster. A good pair of binoculars and a clear night will show four moons serenely orbiting the giant gas ball.
Such visible planetary proximity won't occur again in the Northern hemisphere until 2040. The planets will gather before then, but the sun will be along as well, blocking any view. This week and next our solar system's star has graciously "agreed" to drop below the horizon, setting the stage for the "great planet alignment."
On May 3, Mars and Saturn will lie a mere 2.5 degrees apart. May 4, Mercury will be at its greatest separation from the sun, allowing us to see the "messenger god" with the naked eye for the longest period of the year.
One hour after sunset on May 5, Mars, Saturn and Venus will form a triangle just 3 degrees on each side. May 10, Mars and Venus (the brightest light in the night heavens and about a 100 times as brighter as the muted dusty-red Mars) will be so close they'll almost touch, one-third degree apart, or the tip of a pinkie held at arm's length.
As a finale, on May 14, a sleek crescent moon, mostly dark, will slide within a visible degree from Venus, resplendent in the faint glow of "Earthshine," sunlight reflected from our planet back up on the moon. Consider: The five planets and earthlight on the moon means an observer on Earth can view astronomical events from the sun out to Saturn in one gaze. Awesome!
Giving galactic context to this nocturnal tableau is the red giant star Aldebaran. It will be visible about 8 degrees below and to the left of Venus and is the brightest star of the constellation Taurus. It forms the bull's right eye. From Earth, it looks as big as Mercury, yet it is 50 times the size of our sun. The star is 72 light- years away.
Our sun is a "mere" 8 light- minutes distant (1 light-year equals 6 trillion miles.)