The parent of the now famous Camelopardalid meteor shower offers sky-watchers a challenge this week. They can also focus in on the Guardian of the Great Bear and watch four classic naked-eye planets swing into view.
Comet Challenge. Now that the much hyped but disappointing Camelopardalid meteor shower has come and gone, its parent comet, 209P/LINEAR, makes its closest approach to Earth, starting today, May 27.
Last week it was shining feebly at only 13th magnitude, but predictions point to a quick brightening to 11th magnitude and possibly even 10th magnitude this week. That will make it a worthy target for medium-size telescopes, at least six to eight inches in diameter, under bright suburban skies and for smaller scopes in the dark countryside.
On Thursday the comet will be just five million miles (eight million kilometers) from our planet, about 20 times the distance between Earth and our moon.
Over the course of the week, LINEAR will glide through the low southwestern constellations of Sextans and Hydra, Corvus and Crater, making it an increasingly difficult target for sky-watchers in the Northern Hemisphere. And it will be moving at quite a clip—about half a degree an hour—the same as the width of the full moon.
Check out these detailed finder’s charts from Sky & Telescope.
Arcturus Trio. After nightfall on Wednesday, May 29, look south for three of the brightest “stars” in that part of the sky. At the apex of the triangle is the orange star Arcturus, known in mythology as the “guardian of the bear.” It lies in the kite-shaped constellation Boötes, underneath the constellation Ursa Major, or Big Bear.
Arcturus is considered the fourth brightest star in the entire night sky. It’s truly a giant, some 20 million miles (32,186,880 kilometers) wide—25 times as wide as our sun. Because it’s 36.7 light-years from Earth, we see Arcturus today as it appeared back in April 1977, the month when the U.S. performed a nuclear test in Nevada, Shimon Peres became acting prime minister of Israel, and New York’s Studio 54 disco opened.
The bottom two “stars” of the triangle formation are in fact the planets Saturn and Mars. (Saturn is also part of the constellation Libra, and Mars is part of Virgo.)
Mercury Revealed. On Friday, May 30, look toward the very low western horizon for a razor-thin crescent moon. The moon will be only 6 degrees to the lower left of the faint planet Mercury, the innermost planet in our solar system. The cosmic pair will be only 10 degrees above the local horizon, about the width of your fist held at arm’s length, so you’ll need a clear line of sight.
Moon joins Jupiter. On Saturday, May 31, and Sunday, June 1, the waxing crescent moon will rise higher, taking its place alongside the brilliant planet Jupiter in the afterglow of sunset. Draw an imaginary line from the moon through Jupiter, and the next bright star you will hit, 33 light-years away, is Pollux, one of the of the twin stars in the constellation Gemini, or the Twins.
Happy hunting, everyone.