AstronomyWelcome to by Michael E. Bakich A supplement to Astronomy magazine 618089 KPC ASY • 03/01/14 SH Sky Chart • 4C • 1 PG S Naked-eye astronomy RIE very clear evening when the Sun sets, Starlight, TE the sky darkens and the stars come star bright S Eout. As our local piece of planet Earth As you look at the Y turns away from the Sun and daytime fades constellations, you’ll e M into night, we look out toward the universe. notice that stars dif- th The simplest way to discover the stars is fer in brightness. k S! to begin as the earliest observers began, Astronomers rank c O using just your own two eyes. If this eve- stars on a scale that lo SM ning is clear, why not step outside and spot started with ancient n O a few star patterns? Greek skywatchers. U e C They used six “mag- Getting oriented nitudes.” Current h NEW RESULTS: Planck mission resets the universe’s age t Under the night sky, take a look around. astronomers add f p. 28 o Can you find the Big Dipper in the north? decimals to note OCTOBER 2013 It may be high in the sky and upside-down small steps in bright- The Milky Way glows above Te Waipounamu, the or near the horizon. It’s a bit longer than ness and even negative magnitudes for large southern island of New Zealand. To create Each monthly issue your hand at arm’s length with the fingers bright objects. Just remember that a larger this all-sky image, the photographer combined five 1-minute exposures. TUNÇ TEZEL of Astronomy magazine The world’s best-selling astronomy magazine spread. The Dipper’s stars form part of Ursa magnitude means a dimmer star. is packed with all the tools Major the Great Bear. The two outer stars Every star has a magnitude, but only a in the “bowl” point toward Polaris, the few hundred have names. Many star names apparent only after a few weeks. Typically, you need to get the most TOP 10 North Star. Polaris is part of a constellation come from their place in the constellation they remain visible for months. Mars often from exploring the universe. called Ursa Minor the Little Bear. as described by the ancients. For example, appears bright and red. Jupiter, colored Whether you’re a beginner If you don’t see bears, don’t worry. Con- Rigel, which is Orion the Hunter’s left knee, white, is always bright. Saturn, dimmer EXOPLANETS stellations are invented patterns that began means “left leg of the giant” in Arabic. than Jupiter, looks yellow. The outermost or an experienced stargazer, Of nearly 1,000 distant planets found, as pictures in the sky to help early people Each hour, stars move westward about planets — Uranus and Neptune — glow we explore the most unusual remember important myths and legends. as far as your fist held at arm’s length with weakly and belong in binoculars territory. Astronomy can help you enjoy p. 22 Some constellations, such as spring’s the thumb extended. If you look north, fig- Far outshining any planet is the Moon, every minute under the stars! Leo the Lion, summer’s Scorpius the Scor- ures like the Big Dipper creep around its face mottled with dark lava flows. The pion, and winter’s Taurus the Bull, are pre- Polaris like the hands of a giant clock run- Moon circles Earth, keeping one side See COMET ISON historic. They first appeared in records at ning backward. Besides this daily motion turned toward us. It first appears as a thin in October In the past 20 years, astronomers the dawn of history. Others were invented due to Earth’s rotation, the constellations crescent in the evening sky. Night by night, p. 50 have discovered planets unlike anything in our solar system. Capturing the Sun’s atoms more recently. Today, 88 constellations also slip westward as weeks pass. This sea- the lit portion grows. The half-lit point is Your subscription will include: p. 54 cover the sky with no gaps between them. sonal movement reflects Earth’s yearly called First Quarter because the Moon has AND MORE! travel in its orbit around the Sun. completed one-fourth of its monthly orbit. • Stunning images of the universe 10 GREAT Spice up images No one notices the sky changing from At Full Moon, it is completely lit and floods fall binocular Denkmeier’s with Hydrogen- binocular one night to the next. Yet any given star Earth with reflected sunlight. After Full sights p. 58 • The latest in astronomy and space news alpha p. 60 viewer tested p. 64 rises about four minutes earlier each eve- Moon, the lit portion shrinks. When Last • Monthly columns from the best writers ning due to Earth’s orbital motion. Four Quarter Moon arrives, we see it in daytime in the fi eld minutes difference per day means that after morning hours as well as after midnight. a month, stars rise two hours earlier and set After passing Last Quarter, the Moon • Tips for locating stars, planets, and Subscribers also get two hours sooner. Thus, constellations shrinks to a crescent visible shortly before deep-sky objects slowly drift westward throughout the year. sunrise. Then it reappears low in the west unlimited premium content after sunset, and the cycle begins anew. • All you need to know about the latest BONUS: on Astronomy.com! Wandering “stars” skywatching events Planets don’t reappear regularly each sea- Be prepared son the way stars do because planets con- Star-watching is easy, but a few basic prepa- Find us on Facebook Badge CMYK / .ai stantly orbit the Sun. Yet planets always lie rations make it comfortable. Depending on somewhere along a band of constellations the season, you may want a coat and a ski called the zodiac. cap — or insect repellent. Take a lawn chair Subscribe now and SAVE! Two planets, Mercury and Venus, orbit and a thermos filled with hot cocoa or tea. closer to the Sun than Earth. You will see If you have binoculars, bring them them only before sunrise or after sunset. along. But learning your way around the www.Astronomy.com/promo Mercury in particular is hard to spot, being sky goes better if you start with no optical often low in the twilight. (Binoculars help.) aid at all. Constellation patterns are easiest and enter code IK42A Imagine this photographer’s surprise when a bril- liant bolide (an exploding meteor) superimposed The outer planets (which lie farther to find with the wide-field view your eyes Mon.-Fri., 8:30 a.m.–4:30 p.m. CST. U.S. call 1-800-533-6644 itself on her image of an aurora. The bright dot to from the Sun than Earth) move slowly alone can provide. The next four pages will COVER IMAGES: MATTIAS MALMER/CASSINI IMAGING TEAM (SATURN); ADAM BLOCK/MOUNT LEMMON SKYCENTER (SPIRAL GALAXY); GALAXY); (SPIRAL SKYCENTER LEMMON BLOCK/MOUNT ADAM (SATURN); TEAM IMAGING MALMER/CASSINI MATTIAS IMAGES: COVER ASTRONOMERS) AMATEUR THREE WITH SCENE (HORIZON CLARO MIGUEL MOON); (FULL NASA/GSFC/ASU the far left of the meteor is Jupiter. SHANNON BILESKI among the stars, with changes becoming introduce you to each season’s sky. Outside U.S. and Canada, call 262-796-8776, Ext. 661 WWW.ASTRONOMY.COM 3 P21983 A41A1 Explore the spring sky pring. Finally, it’s warm enough for and it marks the tip even thin-blooded observers to break of the Bear’s tail. Sout their binoculars and telescopes. If Unlike the Big Dip- you’re new to astronomy, however, you’ll per, however, most of want to become familiar with the constella- the other six stars of tions and bright stars that populate this the Little Dipper are season’s night sky before looking through faint. You’ll need a the eyepiece. Then, when you read that a dark location to see sky treat is in Boötes or near Regulus, you’ll them all. already have a frame of reference. Head back to the High in the northeast, the sky’s most Big Dipper, and The constellation Leo the Lion combines a huge recognizable star pattern — the Big Dipper locate its handle. sickle (right) that’s the Lion’s head and a triangle — is easy to spot after sunset. The Dipper is Follow beyond the curve of the handle to of stars (left) that forms its hindquarters and tail. part of the third-largest constellation, Ursa two brilliant stars: Arcturus and Spica. The brightest star is Regulus. BILL AND SALLY FLETCHER Major the Great Bear, but the other stars These two luminaries illustrate some of the are much fainter, so concentrating on the color differences between stars. Go back to the Big Dipper. To find our Big Dipper is the way to start. Arcturus appears copper-colored or next constellation, poke a hole in the Dip- Find the bend of the Dipper’s handle. orange, while Spica is bright blue. Stars have per’s bowl, let all the water run out, and Sharp-eyed observers can see two stars in different colors because nuclear reactions in wait for a loud roar. Mythologically, that’s this space. Arabian astronomers 10 centu- their cores heat their surfaces to different what you’ll hear because the water fell on ries ago called them the Horse and Rider. temperatures. Arcturus is a giant star with a the back of Leo the Lion. The brighter of the two is Mizar, shining relatively cool surface temperature of 7300° Leo’s main figure has two parts: A back- five times brighter than Alcor, which sits a Fahrenheit (4040° Celsius).