The King of Planets

As springtime winds begin to blow, a giant celestial kite sets sail, riding high in the night sky. For sky-watchers, another delightful week is ahead for observing the heavens, with the moon waxing after an early absence and taking a starring role in the celestial encounters ahead.

Springtime kite. With the moon missing for most of the night on Monday, March 31, sky-watchers can track down the distinctive constellation Bootes, the Herdsman, and its red giant star.

A good stargazing trick that will aid observers in finding this bright constellation is to start off at the Big Dipper, now high in the northeastern sky in the late evenings. Appearing to hang upside down, the handle of the Big Dipper offers up three stars that point in an imaginary line down toward the horizon. Follow the line until you hit the next brightest star. Voila, you have found Arcturus, the brightest star of Bootes (see sky map below).

While the remaining five stars that make up the kite shape are quite faint to the naked eye, Arcturus will knock your eyes out.

This sky chart shows the early evening sky looking toward the northeast, where the Big Dipper handle points directly toward Arcturus, the lead star in the constellation Bootes.

That’s because Arcturus is one of the closest stars to us at 37.5 light-years away. It is also considered the fourth brightest star in the entire night sky, and is a real giant at some 20 million miles (32,186,880 kilometers) wide—25 times wider than our sun. If our puny sun were replaced by this behemoth, the outer edge of the star would reach as far as the orbit of Mars, and Earth would be swallowed up by its atmosphere.

Moon and the Bull. After nightfall on Wednesday, April 2, look for the thin crescent moon hanging below the gems of the constellation Taurus, the Bull, low in the western sky.

Nearly straight above the moon is the jewel-like star cluster known as the Pleiades or Seven Sisters. To the naked eye, the 400 light-year-distant, deep-sky treasure trove resembles a fuzzy group of stars. But binoculars and small telescopes bring into the Pleiades stunning focus.

Meanwhile, to the upper left of the moon will be the orange-hued, dying stellar giant Aldebaran, and the distinctively V-shaped Hyades star cluster.

Hyades eclipse. By the next evening, Thursday, April 3, the waxing crescent moon will slide in front of the Hyades cluster. The moon will appear to sit just to the lower right of 65 light-year-distant Aldebaran, which marks the left top of the V-shaped Hyades. Aldebaran may look like part of the cluster, but in reality it is about half as far away as the cluster members are. On Monday, lucky sky-watchers in much of North America will glimpse (through their backyard telescopes) up to three of the Hyades’ fainter members as they are eclipsed, or occulted, by the moon when its unlit portion passes in front of them.

Moon and Jupiter. For those who love planet-watching, Jupiter is easy to find on Saturday, April 6, thanks to the silvery moon pointing the way in the southwestern evening sky. The pair together will make for a spectacular sky sight, even with unaided eyes from brightly lit urban locations.

This sky chart shows Jupiter and the moon together in the constellation Gemini on the evening of April 6.

A near quarter-moon pays a visit to Jupiter, passing only 5 degrees south of the king of planets. Don’t forget to point your binoculars at Jupiter and watch its four largest moons beside it. Even the smallest of telescopes will reveal dark cloud belts and the Great Red Spot, a Jovian hurricane three times the size of Earth.