4 Sky Events This Week: Comet Challenge, Stellar Trio, and Planet Pairings

This image of comet ISON was taken in November 2013, when the comet was 97 million miles from Earth. This week comet 209P/LINEAR will come much closer, but it won’t be as bright, because there’s little dust activity on its surface. Courtesy: NASA/MSFC/Aaron Kingery

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.

This skychart shows the southern sky late evenings in the northern hemisphere where Arcturus, and the planet Mars and Saturn dominate the heavens.  Credit: SkySafari
This chart shows the southern sky during the late evening in the Northern Hemisphere, where Arcturus and the planets Mars and Saturn dominate the heavens. Credit: SkySafari

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.

Skychart showing the western sky at dusk on May 31, 2014 with the crescent Moon,  Jupiter and faint Mercury. Credit: SkySafari
The western sky at dusk on May 31, 2014, shows the crescent moon, Jupiter, and a faint Mercury. Credit: SkySafari

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.


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Changing Planet

Meet the Author
Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.