Mars shines brilliantly and looms large through a telescope this year as it puts on its best display in more than 10 years. NASA/JPL/USGS

By Martin Ratcliffe Skyand Richard Talcott Guide 2016

contents 2 Jan. 2016 A stellar year for Aldebaran 3 Feb. 2016 Jupiter blazes across Leo 4 March 2016 Eclipse over Indonesia 5 April 2016 The Red Planet returns to glory 6 May 2016 Mercury transits the Sun 7 June 2016 Saturn’s summer splendor 8 July 2016 Tracking a recently exposed planet 9 Aug. 2016 The Perseids in prime time 10 Sept. 2016 Ice giants come in from the cold 11 Oct. 2016 Brilliant Venus rules the evening sky 12 Nov. 2016 The Sun’s dynamic face 13 Dec. 2016 A fleeting glimpse of Mercury 14 2017 Preview Looking ahead to next year . . . Martin Ratcliffe provides professional ­planetarium development for Sky-Skan, Inc. 15 Spacecraft A year of exploration Richard Talcott is a senior editor of Astronomy.

618329 A supplement to Astronomy magazine 2016 Jan S M T W T F S A stellar year for 1 3 4 5 6 7 8 10 11 12 13 14 15 Aldebaran 17 18 19 20 21 22 24 25 26 27 28 29 30 uring its monthly out. The star’s orbit around decline may be pro- Earth, the Moon longed if you live passes in front where the occul­ 3 The Moon passes of thousands of tation occurs near 1.5° north of Mars, stars. Most of these distant suns the Moon’s curved 2 p.m. EST D are faint, however, and the so- northern or south- 4 Quadrantid meteor shower peaks called occultations that result ern limb. pass with little notice. Just four A few people 5 Pluto is in conjunc- tion with the Sun, 1st-magnitude stars — Aldeba- will get to witness a 10 p.m. EST ran, Antares, Regulus, and drama-filled grazing 6 Venus passes 6° Spica — lie close enough to the occultation. If you north of Antares, Moon’s path to get in on the view from a line that noon EST action. Aldebaran is 2016’s runs across north- The Moon passes clear winner, with the Moon ern Mexico and the 3° north of Venus, occulting it a dozen times. U.S. Gulf Coast (see 7 p.m. EST Ruddy Aldebaran sat to the upper right of a The best event for North the map below), crescent Moon August 9, 2015. A gibbous Moon The Moon passes American observers occurs the Aldebaran will skim occults the same star January 19. Tunç Tezel 3° north of Saturn, midnight EST evening of January 19. Resi- the Moon’s southern dents across Canada, most of limb, ducking behind though not all of these events 8 Venus passes 0.09° north of Saturn, the United States, and north- mountain ranges and reappear- are created equal. Some of the 11 p.m. EST western Mexico will see an ing in lunar valleys. This graze occultations occur when the 13 The Moon passes occultation. Set up early and track is only a few miles wide, Moon and star lie below the 2° north of Nep- center Aldebaran in your tele- but serious observers often horizon, and others when the tune, 10 a.m. EST scope’s eyepiece. Gradually, the travel large distances to be in Sun shares the sky and reduces 16 The Moon passes dark limb of the waxing gib- the path. Accurately timing the drama. 1.5° south of Ura- bous Moon will approach the when the star disappears and North American observers nus, 1 a.m. EST star. Although most stars dis- reappears gives astronomers have seven opportunities to 19 The Moon passes appear from view instanta- precise information about the see Aldebaran pass behind the 0.5° north of Aldeb- aran, 10 p.m. EST neously, Aldebaran is a red Moon’s limb profile. Moon during 2016. Events giant and likely will take a The Moon occults Aldeba- occur January 19, February 27 The Moon passes 1.4° south of Jupi- tenth of a second or so to fade ran once each orbit this year, 15/16 (western U.S. only), ter, 8 p.m. EST April 10 (daylight), July 29, CANADA August 25 (daylight), October Moon Phases 18/19, and December 12/13. Because the Moon’s orbit First Quarter lies close to the path of the Full Moon UNITED STATES solar system’s planets, Luna also occasionally occults one Last Quarter of Earth’s neighbors. The best aran s Aldeb New Moon ccult planetary occultation this year on o Mo isible The Moon’s he tion v comes September 2 when a T ulta southern limb occ No grazes Aldebaran 1.5-day-old Moon hides Jupi- Events that can be viewed M ter during daylight. Along with the naked eye E X a track from Oregon to the Events that can be viewed I C 0 250 miles O Texas coast, the planet grazes with binoculars 0 500 km the northern lunar limb; peo- Events that can be viewed Jaeger and Kellie : Roen Kelly Astronomy illustrations: All ple south of this line can view with a telescope People north of a line that runs across northern Mexico and southern Texas to the Georgia coast CIR-PB-618329_20will see the Moon occult Aldebaran on January 19. a complete occultation.

2 Sky Guide 2016 2016 Feb Jupiter blazes S M T W T F S 1 2 3 4 5 6 7 9 10 11 12 13 across Leo 14 16 17 18 19 20 21 23 24 25 26 27 28 29 upiter puts on an the star, impressive show and Jupiter throughout this appears as ­winter and spring. if it has Although it doesn’t gained a 1 The Moon passes 3° north of Mars, reach opposition and peak moon. J 4 a.m. EST ­visibility until March 8, few Jupiter 3 The Moon passes observers will notice any reaches oppo- 3° north of Saturn, ­difference in its appearance sition March 8, 2 p.m. EST ­during the longer nights of when it shines 6 The Moon passes January and February. brightest (magnitude 4° north of Venus, As 2016 opens, Jupiter –2.5) and remains visible all 3 a.m. EST Jupiter will look striking through dominates the late evening night. It is unmistakable in the amateur telescopes in the first The Moon passes sky. It rises before 11 p.m. local east as soon as night starts to half of 2016. The planet’s banded 4° north of Mer- time January 1 when it stands fall. The world also appears atmosphere and Great Red Spot cury, noon EST stand out in this image, captured Mercury is at in eastern Leo next to that largest at opposition, span- in December 2000 by the Cassini greatest­ western spacecraft. NASA/JPL/University of Arizona constellation’s border with ning 44" across its equator, elongation (26°), Virgo. The planet starts mov- though it stays above 43" from 8 p.m. EST ing westward relative to the early February to early April. near the planet, it means one 9 The Moon passes background stars just a week Any telescope delivers stun- or more of the moons is hiding 2° north of Nep- later, however, which carries it ning views of the giant planet. behind Jupiter’s disk or passing tune, 7 p.m. EST into the sparsely lit region of The smallest instruments in front of it. 12 The Moon passes southeastern Leo. Shining reveal two dark equatorial Larger scopes reveal finer 1.7° south of Ura- brighter than magnitude –2, belts straddling a brighter zone detail in the jovian atmosphere. nus, 9 a.m. EST Jupiter is the lone standout. that coincides with the planet’s A series of alternating bright 16 The Moon passes The giant world’s path has equator. Also look for Jupiter’s zones and darker belts comes 0.3° north of Aldeb- aran, 3 a.m. EST it heading straight for 4th- four biggest moons, which into view as do turbulent fea- σ 23 The Moon passes magnitude Sigma ( ) Leonis. change positions from night to tures in the swirl of clouds near 1.7° south of Jupi- On the night of March 2/3, the night and often by the hour. If the borders of these bands. ter, 11 p.m. EST planet passes just 14' south of you don’t see four bright dots Jupiter remains a fasci­ 28 Neptune is in con- nating target throughout the junction with the N spring. On April 7/8, it slides Sun, 11 a.m. EST 7' north of 5th-magnitude Chi 29 The Moon passes (χ) Leonis. And it remains on 4° north of Mars, 1 p.m. EST LEO May 10 view past midnight local day- April 10 light time as late as early July. χ Although it dips lower as March 10 summer progresses, keep an E σ eye on Jupiter. On August 27, it has a fine conjunction with Feb 10 Jupiter reaches opposition March 8 Venus. The sky’s two brightest Jan 10 points of light then lie 5' apart and stand 5° above the western τ horizon 30 minutes after sun- 1° set. Jupiter passes behind the Sun in late September and a few weeks later returns to view The solar system’s biggest planet shines brilliantly nearly all night this winter and spring. It spendsCIR-PB-618329_21 this peak period in southeastern Leo, not far before dawn, where it remains from the border with Virgo. through the end of 2016.

www.Astronomy.com 3 2016 20% March 60% S M T W T F S Eclipse over Greatest eclipse

2 3 4 5 60%

6 7 9 10 11 12 20% 13 14 16 17 18 19 Indonesia Path of totality 20 21 22 24 25 26 27 28 29 30 wo solar eclipses Limit of eclipse grace Earth’s sky visibility

M in 2016, but the A L A most spectacular Y A S SI 2 The Moon passes IA AY will be the total AL 4° north of Saturn, M eclipse of March 8/9. People S SINGAPORE 2 a.m. EST T U along a narrow track that M A BORNEO 3 Asteroid Ceres is in T crosses parts of Indonesia and R conjunction with A ity the Sun, 5 p.m. EST the Pacific Ocean will witness Path of total SULAWESI 7 The Moon passes one of nature’s greatest spec- Java Sea 4° north of Venus, tacles as the Moon completely 6 a.m. EST blocks the Sun’s bright disk INDONESIA 8 Jupiter is at oppo­ and reveals our star’s ethereal INDIAN OCEAN JAVA sition, 6 a.m. EST outer atmosphere, the corona. BALI Total solar eclipse, The total eclipse begins 0 400 miles 9 p.m. EST when the Moon’s dark umbral 0 400 km 10 The Moon passes shadow first touches Earth at The March 9 path of totality crosses Sumatra, Borneo, and Sulawesi, as well 1.9° south of Ura­ sunrise March 9 west of the as several smaller islands in the Indonesian archipelago. nus, 8 p.m. EST Indonesian island of Sumatra. 14 The Moon passes The shadow then island-hops People in Hawaii will expe- at the 5:37 p.m. peak, when the 0.3° north of Aldeb­ aran, 10 a.m. EDT for about 40 minutes, crossing rience a significant partial two objects stand 14° above Sumatra, Borneo, Sulawesi, eclipse late on the afternoon of the western horizon. At the 20 Equinox (northern spring/southern and some smaller islands March 8 — seemingly a day same moment, observers along autumn begins), before heading northeast early because the Moon’s the Big Island’s Kona coast will 1 a.m. EDT across the Pacific for another shadow has crossed the Inter- see a 64 percent partial eclipse. Venus passes 0.5° two-and-a-half hours. The national Date Line. From Much of Alaska also falls south of Neptune, eclipse peaks well out in the Honolulu, the eclipse begins at under the Moon’s shadow. From 10 a.m. EDT ocean, where the Moon hides 4:33 p.m. HAST and lasts until Anchorage, the eclipse starts at 21 The Moon passes the Sun’s disk for 4 minutes 6:33 p.m. The Moon hides 70 5:38 p.m. AKST with the Sun 7° 2° south of Jupiter, midnight EDT and 9 seconds. percent of the Sun’s diameter above the horizon and peaks at 6:12 p.m. Luna then covers 19 23 Penumbral lunar eclipse, 8 a.m. EDT percent of the Sun’s diameter. The Moon and Sun align Mercury is in supe­ rior conjunction, for the year’s second solar 4 p.m. EDT eclipse September 1. Unfor­ 28 The Moon passes tunately, the Moon then lies 4° north of Mars, farther from Earth than it did 3 p.m. EDT March 8/9 so it appears too 29 The Moon passes small to cover the entire solar 3° north of Saturn, disk. Instead, people along a 11 a.m. EDT narrow path in central Africa will see the Moon pass directly in front of the Sun but fail to cover the whole disk, leaving a bright ring visible. This so- called annular eclipse peaks in southern Tanzania where the A diamond ring flashes into brilliance during the November 14, 2012, total solar eclipse in Australia. Observers eagerly await similarly stunning sights ring of sunlight lasts 3 minutes from Indonesia on March 9. Mike Reynolds and 6 seconds.

4 Sky Guide 2016 2016 The Red Planet April S M T W T F S 1 2 returns to glory 3 4 5 6 8 9 10 11 12 14 15 16 17 18 19 20 21 23 24 25 26 27 28 30 Antares, which appears 5° to 2014. Mars’ diameter remains the south. above 14" well into July. Be sure to check out the The planet’s large apparent colors of the three objects. size offers a visual feast for Saturn displays a yellow Mars’ aficionados. Northern 4 The Moon passes 1.9° north of Nep- hue while the other two Hemisphere observers do face tune, 9 p.m. EDT appear a similar shade a challenge, however, because 6 The Moon passes of orange-red. By the the world resides well south of 0.7° north of Venus, way, the name Antares the celestial equator and thus 4 a.m. EDT means “rival of Ares,” never climbs high in the sky. 8 The Moon passes Ares being the Greek god It peaks about 30° above the 5° south of Mer- of war (the same role played southern horizon from mid- cury, 7 a.m. EDT by the Roman god Mars). The northern latitudes. 9 Uranus is in con- “rivalry” stems from the nearly Mars experiences seasons, junction with the Mars glows brightly this spring as it Sun, 5 p.m. EDT makes its closest approach to Earth identical colors. but because its “year” is 10 The Moon passes since 2005. Steve Lee (University of Colorado)/ During the next several almost twice as long as Earth’s, 0.3° north of Aldeb- Jim Bell (Cornell University)/Mike Wolff (SSI)/NASA weeks, Mars brightens rapidly so are its seasons. The planet’s aran, 6 p.m. EDT and grows dramatically larger northern hemisphere is in the 18 The Moon passes fter a wait of two as it approaches opposition midst of summer during the 2° south of Jupiter, years, Mars puts on and peak visibility May 22. It run-up to opposition, with the 1 a.m. EDT another marvel- glows brightest around oppo- autumnal equinox arriving in Mercury is at ous display in sition (peaking at magnitude early July. This means observ- greatest­ eastern Earth’s sky. But –2.1) when it rises at sunset ers can follow the retreat of elongation (20°), Athis isn’t just any apparition and remains visible all night. the north polar cap through- 10 a.m. EDT for Earth’s neighbor — the The planet appears slightly out this period. Also look for 22 Lyrid meteor Red Planet shines brighter larger when it comes closest to Syrtis Major, the most obvious shower peaks and appears larger through Earth on May 30, cresting at dark feature on Mars’ surface. 24 The Moon passes 5° north of Mars, a telescope than at any time an apparent diameter of 18.6". Several other dark features midnight EDT since 2005. The sign that good That’s 22 percent bigger than show up during moments of 25 The Moon passes Mars viewing has begun at its previous peak in April good seeing. 3° north of Saturn, comes when the planet ends 3 p.m. EDT its normal eastward motion N 26 Asteroid Juno is relative to the background γ at opposition, stars April 16 and starts its 11 p.m. EDT so-called retrograde loop. Mars then shines at magni- OPHIUCHUS tude –1.0 and spans 14" when Mars reaches opposition May 22 ν viewed through a telescope. χ β κ This is plenty big enough to ω1 E show surface detail through 15 30 April 15 June 1 a 4-inch instrument, though May 1 15 ρ M80 LIBRA bigger scopes improve the δ view. The ruddy world rises around 11 p.m. local daylight σ π time and appears highest in Antares the south before dawn. Mars SCORPIUS υ τ 2° shares this region with magni- tude 0.3 Saturn, which lies 7° The Red Planet spendsCIR-PB-618329_23 the peak of its 2016 apparition moving westward to the east, and magnitude 1.1 against the background stars of Ophiuchus, Scorpius, and Libra.

www.Astronomy.com 5 2016 May S M T W T F S Mercury transits 1 2 3 4 5 7 8 9 10 11 12 14 15 16 17 18 19 20 the Sun 22 23 24 25 26 27 28 30 31 ransiting planets are all the rage. The Kepler spacecraft has discovered 2 The Moon passes thousands of exo- 1.7° north of Nep­ planets by detecting the small tune, 7 a.m. EDT T drop in starlight that occurs 4 The Moon passes 2° south of Uranus, when a planet passes in front 11 p.m. EDT of its parent sun. Well, this 5 Eta Aquariid month you can see a transiting meteor shower planet from your own yard! peaks On May 9, Mercury transits 8 The Moon passes the Sun for the first time since 0.5° north of Aldeb­ November 8, 2006. Observers aran, 5 a.m. EDT across the Americas as well as 9 Mercury transits in Europe, Africa, and much the Sun, 11 a.m. EDT of Asia can view this event. Mercury’s tiny black disk crossed the Sun’s face November 8, 2006, during The Moon passes 15 Transits of Mercury occur the innermost planet’s most recent transit of our star. Bill Hood 2° south of Jupiter, 6 a.m. EDT 13 or 14 times each century when the planet’s orbit brings a.m. PDT), well after sunup view the transit, but make sure 21 The Moon passes 6° north of Mars, it directly between the Sun and across the continent, when to protect your eyesight. For a 4 p.m. EDT Earth. Although Mercury zips Mercury lies 319" from the direct view, place a safe solar 22 Mars is at oppo­ around the Sun at an average center of the solar disk. The filter over your instrument’s sition, 7 a.m. EDT speed of 107,000 mph, it will planet exits the brilliant disk front end. Alternatively, you The Moon passes take the innermost planet around 2:42 p.m. EDT (11:42 can project the Sun’s image 3° north of Saturn, 7.5 hours to cross the Sun’s a.m. PDT). These times are onto a white card to allow sev- 6 p.m. EDT face May 9. for a hypothetical observer at eral people to view the transit 23 Asteroid Vesta is in The event begins around Earth’s center; actual times may simultaneously. Place the card conjunction with 7:12 a.m. EDT, not long after differ by a couple of minutes. 12 to 18 inches from the eye- the Sun, 3 p.m. EDT the Sun rises in eastern North Mercury’s disk spans 12", a piece to enlarge the Sun’s disk 29 The Moon passes America. Mid-transit occurs tiny fraction of the Sun’s 1,901" and use sunspots or Mercury’s 1.4° north of Nep­ tune, 3 p.m. EDT about 10:57 a.m. EDT (7:57 girth. You’ll need a telescope to disk to focus the image.

EUROPE NORTH AMERICA Entire ASIA transit visible T

r

a n AFRICA s t i t e t T s e b r s n a SOUTH e n u n g u s s i AMERICA s t i n t t a s e a s n a s n d t i s d g AUSTRALIA s u n e e a n b t r it t s is s i u e n s Transit n a an ri Tr r not Transit se T visible not visible

People across the Americas, Europe, Africa, and muchCIR-PB-618329_24: of Asia can watch Mercury transit the Sun on May 9.

6 Sky Guide 2016 2016 June Saturn’s summer S M T W T F S 1 2 3 5 6 7 8 9 10 11 splendor 13 14 15 16 17 18 19 21 22 23 24 25 26 28 29 30 n the heels of Mars’ late May opposi- tion, Saturn follows suit less 1 The Moon passes 2° south of Uranus, than two weeks later. On June O Saturn’s rings open wider this year 10 a.m. EDT 3, the ringed planet lies oppo- than they have since 2004. At the Saturn is at oppo­ planet’s peak in early June, they 3 site the Sun in our sky and brighter than 1st-magnitude sition, 3 a.m. EDT remains on view all night. The Antares to the south. tilt 26° to our line of sight and should look spectacular through The Moon passes majestic world spends the year Saturn looks absolutely any telescope. NASA/ESA/E. Karkoschka 0.7° south of Mer­ within the confines of Ophiu- stunning through a telescope (University of Arizona) cury, 6 a.m. EDT chus, nestled between the around opposition. The plan- 5 Mercury is at brighter constellations Scor- et’s subtly shaded yellowish through 4-inch instruments. greatest­ western pius and Sagittarius. disk measures 18.4" across Enceladus glows at 12th mag- elongation (24°), As you might guess, the while the spectacular rings nitude and orbits closer to the 5 a.m. EDT proximity of their opposition span 41.8" and tilt 26° to our rings, making it a challenge 6 Venus is in superior conjunction, dates means Mars and Saturn line of sight. The severe tilt even in larger scopes. 6 p.m. EDT appear near each other in the offers exquisite views of the Although Titan has a 11 The Moon passes sky. The two lie 7° apart in ring system’s structure, includ- thick atmosphere with liquid 1.5° south of Jupi­ mid-April and then pull apart ing the dark Cassini Division hydrocarbon seas on its sur- ter, 4 p.m. EDT slowly as the Red Planet that divides the outer A ring face and Enceladus blasts 17 The Moon passes begins its more rapid retro- from the brighter B ring. plumes of water into space, 7° north of Mars, grade loop. By the time Saturn A small telescope also Iapetus may well be the most 6 a.m. EDT reaches opposition in early reveals an obvious companion intriguing saturnian moon. 18 The Moon passes June, 16° separate the two. — Saturn’s 8th-magnitude One of its hemispheres is as 3° north of Saturn, Saturn then shines at magni- moon, Titan. Several fainter bright as snow while the 8 p.m. EDT tude 0.0, its brightest for the moons orbit closer in. Easiest opposite side appears as black 19 Mercury passes 4° north of Aldebaran, year. Although significantly to spot are the 10th-magnitude as coal. During its 79-day 5 p.m. EDT dimmer than Mars, the ringed trio of Tethys, Dione, and orbit, Iapetus turns its diverse 20 Solstice (northern planet appears noticeably Rhea, which typically show up faces toward Earth. It shines summer/southern at 10th magnitude when far winter begins), N west of the planet but two 7 p.m. EDT magnitudes dimmer when 25 The Moon passes it’s far to the east. Look for it 1.2° north of Nep­ χ around greatest western elon- tune, 9 p.m. EDT OPHIUCHUS gation the night of June 21/22. 28 The Moon passes Planetary motions bring 3° south of Uranus, 7 p.m. EDT July 1 31 June 1 Mars back to Saturn’s vicinity May 1 in late August. The Red Planet E April 1 Saturn reaches passes 4° south of Saturn on opposition June 3 ω the 25th, two days after Mars slides 2° north of Antares. Saturn has another pretty ρ ­conjunction, this time with Venus, on October 29 and 30. 1° The ringed planet then stands 3° north of its brilliant neigh- The ringed planet resides among the background stars of southwestern Ophiuchus at its best thisCIR-PB-618329_25 year. The gas giant world peaks at magnitude 0.0 bor in the southwestern sky and shines noticeably brighter than any nearby star. after sunset.

www.Astronomy.com 7 2016 July Tracking a recently S M T W T F S 1 2 3 5 6 7 8 9 10 12 13 14 15 16 exposed planet 17 18 20 21 22 23 24 25 27 28 29 30 he New Horizons N 31 spacecraft forever changed our per- ception of Pluto. π 1 The Moon passes Before the plucky Pluto reaches opposition July 7 0.4° north of Aldeb- probe flew past the distant aran, midnight EDT T dwarf planet, scientists knew Mercury is in supe- June 24 6 little about this world beyond rior conjunction, E 28 11 p.m. EDT the presence of exotic surface July 2 6 7 Pluto is at opposi- ices, a thin escaping atmo- 10 tion, 6 p.m. EDT sphere, and five moons. Millions of people around 9 The Moon passes SAGITTARIUS 0.9° south of Jupi- the world eagerly followed ter, 6 a.m. EDT the historic July 2015 flyby. The Moon passes 14 Breathtaking images revealed 0.05° 8° north of Mars, towering mountains of water 2 p.m. EDT ice, a vast equatorial glacier Northeastern SagittariusCIR-PB-618329_26 is home to Pluto this year. The 14th-magnitude 16 The Moon passes composed of frozen nitrogen speck passes 2.7' south of Pi (π) Sagittarii on June 26. 3° north of Saturn, 1 a.m. EDT and carbon monoxide, a heart- shaped ice region informally the spirit of the moment dur- Luckily, the Moon is gone Mercury passes 0.5° north of Venus, named Tombaugh Regio, ice ing a press conference three from the evening sky during 2 p.m. EDT flows, craters, and signs of days after the encounter when this period. Your best chance 23 The Moon passes recent geologic activity. he said, “I think the solar sys- for spotting Pluto in the eye- 1.1° north of Nep- Alan Stern of the Southwest tem saved the best for last.” piece comes if you observe tune, 2 a.m. EDT Research Institute in Boulder, The New Horizons revela- from a site far removed from 25 The Moon passes Colorado, principal investiga- tions haven’t changed the fact the lights of the city. 3° south of Uranus, tor of New Horizons, captured that Pluto looks like a dim Now you’re ready to zero midnight EDT speck when viewed through a in on your target. Pluto lies 29 The Moon passes telescope, but the sight of that in northeastern Sagittarius 0.3° north of Aldeb- aran, 7 a.m. EDT faint dot now evokes images among a triangle of 3rd- and of an icy wonderland. 4th-magnitude stars: Pi (π), 30 Mercury passes 0.3° 2 2 north of Regulus, People who never Omicron (ο), and Xi (ξ ) Sag- 1 p.m. EDT thought twice about ittarii. This tight group lies observing the world due north of the handle in now want to see it the Archer’s conspicuous Tea- for themselves. pot asterism. Fortunately, the Use magnitude 2.9 Pi Sgr as task proves easier your guide. On June 26, Pluto this year than most passes 2.7' due south of Pi. By thanks to Pluto’s the time the planet reaches proximity to a opposition July 7, it has moved naked-eye star in noticeably, to a position 18' ­Sagittarius the Archer. west-southwest of the star. If The solar system object you can’t tell which point of appears at its best in late June light Pluto is, sketch five or six Pluto emerged from the shadows in and early July. It then glows stars near its position and July 2015 when the New Horizons dimly at magnitude 14.1, so come back to the same field a spacecraft flew past and returned the first close-up images of the you’ll need an 8-inch or larger night or two later. The “star” distant world. NASA/JHUAPL/SwRI telescope to track it down. that moved is Pluto.

8 Sky Guide 2016 2016 The Perseids in Aug S M T W T F S 1 3 4 5 6 prime time 7 8 9 11 12 13 14 15 16 17 19 20 21 22 23 25 26 27 28 29 30 31

4 The Moon passes 3° south of Venus, 2 a.m. EDT The Moon passes 0.6° south of Mer­ cury, 6 p.m. EDT 5 Venus passes 1.1° north of Regulus, 5 a.m. EDT The Moon passes 0.2° south of Jupi­ ter, midnight EDT Three Perseid meteors streaked across the sky almost simultaneously at the peak of the 2015 shower. Jamie Cooper 11 The Moon passes 8° north of Mars, he Perseid shower swarm. The particles enter our You’ll see the most meteors 6 p.m. EDT is a mainstay of the atmosphere at a blistering if you observe under a dark 12 The Moon passes annual meteor cal- 37 miles per second and get sky. Consider reclining in a 4° north of Saturn, endar because it incinerated by friction, creat- lawn chair or lying on an air 8 a.m. EDT has a high rate of ing the streaks of light. mattress. Look roughly two- Perseid meteor T“shooting stars” and it occurs In a typical year, observers thirds of the way from the shower peaks on warm summer nights. The under dark skies can see up to horizon to the zenith and 16 Mercury is at shower peaks this year before 100 meteors per hour at the roughly 40° to 60° from greatest­ eastern dawn August 12, conveniently peak if the radiant lies over- the radiant. elongation (27°), timed with the Moon out of head. But astronomers think The Perseids should be this 5 p.m. EDT the sky (the waxing gibbous we might get an even better year’s finest meteor shower. 18 Penumbral lunar eclipse, 5 a.m. EDT sets around 1 a.m. local day- performance this year. Cal­ Although January’s Quadran- light time). That leaves more culations show that Jupiter’s tids and May’s Eta Aquariids 19 The Moon passes 1.1° north of Nep­ than three hours of darkness gravity recently shifted part of both occur under Moon-free tune, 8 a.m. EDT before twilight starts to paint the comet’s dust stream closer skies, they don’t typically pro- 20 Asteroid Pallas is the sky. The meteors appear to to Earth’s orbit, and our planet duce as good a show. And at opposition, radiate from the constellation will be crossing this section in bright moonlight will wash 8 a.m. EDT Perseus (hence the shower’s 2016. If so — and that’s a big out the fainter members of 22 The Moon passes name), a region that climbs “if” — observers under opti- October’s Orionid, Novem- 3° south of Uranus, high shortly before dawn. mal conditions could witness ber’s Leonid, and December’s 6 a.m. EDT The Perseids derive from 150 meteors per hour. Geminid showers. 23 Mars passes 1.8° debris laid down by Comet north of Antares, midnight EDT 109P/Swift-Tuttle. This peri- Meteor showers in 2016 odic visitor returns to the 25 The Moon passes Name Peak date Moon’s phase Prospects 0.2° north of Aldeb­ inner solar system every 130 aran, 1 p.m. EDT years or so, and each time it Quadrantids Jan. 4 Waning crescent Good Lyrids April 22 Full Moon Poor Mars passes 4° does, the Sun boils off some south of Saturn, of its ices, releasing tiny dust Eta Aquariids May 5 New Moon Excellent 2 p.m. EDT Perseids Aug. 12 Waxing gibbous Good particles in the process. Over 27 Venus passes 0.07° the eons, these specks have Orionids Oct. 21 Waning gibbous Poor north of Jupiter, spread out to fill the comet’s Leonids Nov. 17 Waning gibbous Poor 6 p.m. EDT orbit, and every August Earth Geminids Dec. 13 Full Moon Poor plunges through the dense

www.Astronomy.com 9 2016 Sept S M T W T F S Ice giants come in 2 3 4 5 6 7 8 10 11 12 13 14 15 17 from the cold 18 19 20 21 22 24 25 26 27 28 29 wo major planets N dominate the outer φ solar system. Ura- λ nus has about 15 ρ θ 1 Annular solar times the mass of eclipse, 5 a.m. EDT Neptune TEarth while Neptune tips the 2 Neptune is at scale at 17 Earth masses. Sci- opposition, entists refer to the pair as “ice σ 1 p.m. EDT E giants” to differentiate them The Moon passes AQUARIUS 0.4° north of Jupi­ from their larger gas giant ter, 6 p.m. EDT cousins Jupiter and Saturn. τ 3 The Moon passes (By “ice,” astronomers mean 1.1° north of Venus, they have large amounts of 7 a.m. EDT compounds such as water δ 8 The Moon passes and methane in their interiors 1° 4° north of Saturn, compared with the hydrogen 5 p.m. EDT and helium that dominate the The ice giant world Neptune resides among the background stars of Aquarius the Water-bearerCIR-PB-618329_27 this year. At opposition September 2, the 9 The Moon passes gas giants.) 8° north of Mars, magnitude 7.8 planet lies within 2° of 4th-magnitude Lambda (λ) Aquarii. The chart shows stars to magnitude 8.5, so identification should be a snap. 10 a.m. EDT Both ice giants make tempt- ing targets this autumn. Nep- 12 Mercury is in infe­ rior conjunction, tune reaches opposition and slides 31' due south of Lambda. Lambda’s southwest. But by 8 p.m. EDT peak visibility September 2 The ice giant then rises around year’s end, it has a more nota- 15 The Moon passes while Uranus follows in mid- 10 p.m. local daylight time and ble companion. Mars’ rapid 1.2° north of Nep­ October. Identifying Neptune appears highest before dawn. eastward motion carries it tune, 4 p.m. EDT hasn’t been this easy for years. Once opposition arrives in Sep- within 13' of Neptune on New 16 Penumbral lunar After wandering through a tember, it rises at sundown and Year’s Eve. Mars then shines at eclipse, 3 p.m. EDT star-poor region of southern is nicely placed by midevening. magnitude 0.9 and Neptune is 17 Venus passes 3° Aquarius, this year the planet The planet spends the rest some 630 times dimmer, at north of Spica, ventures close to magnitude 3.7 of 2016 in the evening sky to magnitude 7.9. Through a tele- 7 p.m. EDT Lambda (λ) Aquarii. You can scope, the Red Planet displays 18 The Moon passes find Lambda 23° south of mag- a ruddy disk that spans 5.7" 3° south of Uranus, α 1 p.m. EDT nitude 2.5 Alpha ( ) Pegasi, while the ice giant appears the star at the southwest- 2.2" across and blue-gray. 21 The Moon passes 0.2° north of Aldeb­ ern corner of the Great Uranus lies in southern aran, 7 p.m. EDT Square of Pegasus. Pisces, one constellation 22 Equinox (northern Neptune lies less east of Neptune. Glow- autumn/southern than 2° southwest of ing at magnitude 5.7 at spring begins), Lambda throughout its October 15 opposi- 10 a.m. EDT September. At oppo- tion, Uranus shows up 26 Jupiter is in con­ sition on the 2nd, the easily through binoculars junction with the Sun, 3 a.m. EDT planet glows at magni- and even to the naked eye tude 7.8, making it an under a dark sky. (Opposi- 28 Mercury is at greatest­ western easy binocular object in tion does not offer a dark sky, elongation (18°), the same field as Lambda. however — the Full Moon lies 4 p m . . EDT Neptune approaches even Neptune shows a distinctive a few degrees away.) The ice 29 The Moon passes closer to Lambda in July. On blue-gray cast when viewed giant world spends October 0.7° south of Mer­ the 11th, the planet appears through amateur telescopes. The just north of a line joining the cury, 7 a.m. EDT color appeared even more dramatic 28' south-southeast of the star. to Voyager 2’s cameras when the 5th-magnitude stars Zeta (ζ) And on the 24th, Neptune probe flew by in 1989.NASA/JPL and Mu (μ) Piscium.

10 Sky Guide 2016 2016 Brilliant Venus rules Oct S M T W T F S 1 the evening sky 2 3 4 5 6 7 8 10 11 12 13 14 15 17 18 19 20 21 23 24 25 26 27 28 29 or one planet, 2016 is an odd year. 31 Venus experiences no greatest eastern or western elonga- 3 The Moon passes 5° north of Venus, tion, the first time this has F 1 p.m. EDT happened since 2008. Every 6 The Moon passes eight years, the inner planet 4° north of Saturn, reaches superior conjunction 4 a.m. EDT (passing on the far side of the 8 The Moon passes Sun) in June. This means it 7° north of Mars, reached western elongation in 8 a.m. EDT October 2015 and won’t come 10 Mercury passes to eastern elongation again 0.9° north of Jupi­ until January 2017. ter, midnight EDT Following its June 6 supe- 13 The Moon passes 1.2° north of Nep­ rior conjunction, Venus tune, 2 a.m. EDT returns to the evening sky. It Uranus is at oppo­ shines brilliantly in the west 15 A waxing crescent Moon passed within a few degrees of Venus on the sition, 7 a.m. EDT during twilight in August and evening of September 8, 2013. The two brilliant objects will have a The Moon passes September, though it remains similarly stunning encounter October 3. Jared Bowens 3° south of Uranus, low. It finally climbs into a 10 p.m. EDT dark sky during October. 30 minutes. The Moon appears 77 percent lit and on 19 The Moon passes You’ll want to be sure to appears 8 percent lit while a December 3 it is 68 percent lit. 0.3° north of Aldeb­ look for it October 3, when a telescope reveals that Venus is Venus spends the first half aran, 3 a.m. EDT waxing crescent Moon passes 85 percent illuminated. The of October among the back- 21 Orionid meteor within 5° of the planet. The Moon returns to the planet’s ground stars of Libra, then shower peaks pair lies about 10° high in the vicinity twice more in 2016, crosses into Scorpius on the Asteroid Ceres is west-southwest a half-hour and Venus shows a dimin- 17th and Ophiuchus on the at opposition, 1 a.m. EDT after sunset and remains an ished phase each time. On 24th. One evening later, the impressive sight for another November 2, the planet world stands 3° north of 1st- 25 Venus passes 3° north of Antares, magnitude Antares. And four midnight EDT nights after that, the planet OPHIUCHUS 27 Mercury is in supe­ passes 3° south of Saturn. At rior conjunction, magnitude –4.0, Venus far noon EDT Saturn outshines all its neighbors. 28 The Moon passes The planet pushes into Sagit- 1.4° north of Jupi­ Antares tarius on November 9 and ter, 6 a.m. EDT Venus passes 3° SCORPIUS LIBRA Capricornus on December 7, 30 climbing higher into a darker south of Saturn, Moon VIRGO 4 a.m. EDT sky with each passing week. Venus also appears in the Venus eastern sky before dawn early 5° in the year. The premier win- ter event occurs January 9 October 3, 30 minutes after sunset when Venus passes a mere 5' Looking west-southwest north of Saturn. The pair rises Shortly after the Sun goes down October 3, look for brilliant Venus just more than two-and-a-half below the waxing crescentCIR-PB-618329_28 Moon. hours before the Sun.

www.Astronomy.com 11 2016 Nov S M T W T F S The Sun’s 1 2 3 4 5 6 8 9 10 11 12 13 15 16 17 18 19 dynamic face 20 22 23 24 25 26 27 28 30 ith winter approaching and the nights grow- 2 The Moon passes ing colder, 4° north of Saturn, observers often shudder at the 3 p.m. EDT W thought of spending hours The Moon passes 7° north of Venus, under the stars. But there’s a midnight EDT solution to this problem hiding 6 The Moon passes in plain sight — our own star, 5° north of Mars, the Sun. Not only does it pro- 7 a.m. EST vide plenty of light for viewing, 9 The Moon passes but it’s also up in the daytime. 1.0° north of Nep- You can see amazing features tune, 10 a.m. EST through a small telescope and 12 The Moon passes not lose any sleep — a true 3° south of Uranus, win-win situation! 6 a.m. EST The Sun’s fierce brilliance 15 The Moon passes 0.4° north of Aldeb- makes safety a top concern, aran, noon EST however. Direct sunlight can Dark filaments snake across the Sun’s disk while orange-red prominences arch above the solar limb in this Hydrogen-alpha image. Craig and Tammy Temple 17 Leonid meteor permanently damage your ret- shower peaks ina in a fraction of a second. 18 Mercury passes 3° To directly view the Sun, use regions in the solar photo- Under good seeing condi- north of Antares, only a safe solar filter that fits sphere (its visible surface) tions, you also may see granu- 4 p.m. EST snugly over the front end of change appearance from day lation. Continual churning of 24 The Moon passes your telescope. If you use a to day and sometimes by the hot gases in the solar photo- 1.9° north of Jupi- Hydrogen-alpha (Hα) filter hour. Isolated spots are com- sphere causes this rice-grain ter, 9 p.m. EST or scope, make sure all of its mon, but dozens can gather pattern. Rising columns of hot 29 Asteroid Juno is in components are secure. in complex active regions. gas appear slightly brighter conjunction with the Sun, 3 p.m. EST A view of the Sun in (fil- Sunspots arise when strongly than the cooler descending tered) white light can be mes- bunched magnetic fields regions that surround them. 30 The Moon passes 7° north of Mer- merizing. Sunspots stand out impede the regular flow of In contrast to a white-light cury, 11 p.m. EST vividly. These dark, cooler heat from the solar interior. filter, a Hα filter reveals addi- tional features by transmitting only red light at a wavelength of 656.3 nanometers. Dark fila- ments appear to snake across the surface, created by mag- netic fields raising cooler hydrogen gas into high arches that look black against the solar disk. When viewed at the Sun’s limb, however, these arches appear as bright protrusions called “prominences” that can change by the minute. Hα fil- ters also reveal bright “plages” You never know what you might see when viewing the Sun. Here, a solar surrounding sunspots and on prominence gives birth to a coronal mass ejection. SDO/NASA rare occasions a solar flare.

12 Sky Guide 2016 2016 A fleeting glimpse Dec S M T W T F S 1 2 3 of Mercury 4 5 6 8 9 10 11 12 14 15 16 17 18 19 21 22 23 24 25 26 27 28 30 31 ercury swings through Sag- ittarius dur- ing the first 3 The Moon passes 6° north of Venus, half of December in one of its M 8 a.m. EST best evening shows of the year. 5 The Moon passes Because the innermost planet 3° north of Mars, follows a Sun-hugging orbit, it 6 a.m. EST appears low in the sky shortly 6 The Moon passes after sunset or before sunrise 0.7° north of Nep- when near a greatest elonga- tune, 5 p.m. EST tion from our star. Its visibility 9 The Moon passes also depends on the angle of 3° south of Uranus, the ecliptic — the apparent 3 p.m. EST path of the Sun and planets 10 Saturn is in con- junction with the across the sky — to the hori- Sun, 7 a.m. EST zon, with steeper being better. Mercury glows in false colors in this image from the MESSENGER Mercury is at You can first glimpse Mer- spacecraft, whose mission ended April 30, 2015. Through amateur greatest­ eastern cury on December 1. Look for scopes, the innermost planet shows a featureless disk. NASA/JHUAPL/CIW elongation (21°), a two-day-old Moon hanging midnight EST some 15° above the southwest- As Mercury crosses Sagit- Use binoculars or a small tele- 12 The Moon passes ern horizon a half-hour after tarius, it seems to gain a moon scope for the best view. 0.5° north of Aldeb- sunset. Using binoculars, then December 7. The intruder is Mercury reaches greatest aran, midnight EST drop 10° directly below the actually a star, magnitude 2.8 elongation December 10 13 Geminid meteor Moon to pick up Mercury. The Lambda (λ) Sagittarii, which when it lies 21° east of the shower peaks planet shines brightly enough, forms the top of the lid in the Sun. That evening, you can 18 The Moon passes 1.0° south of Regu- at magnitude –0.5 (as it does constellation’s Teapot asterism. find the world nearly 10° high lus, 2 p.m. EST for the next two weeks), to From North America, the two in the southwest 30 minutes 21 Solstice (northern pierce the twilight glow. pass within 9' of each other. after sunset. It maintains this winter/southern altitude for another week but summer begins), then drops toward the Sun 6 a.m. EST and dims rapidly. It disap- 22 The Moon passes Venus pears about a week before 2° north of Jupiter, passing between the Sun and noon EST Earth on the 28th. 27 The Moon passes Mercury’s speedy orbital 4° north of Saturn, 4 p.m. EST motion guarantees several 28 Mercury is in infe- apparitions during the course rior conjunction, of the year. It appears some- 2 p.m. EST Mercury what higher and in a darker sky on evenings around its SAGITTARIUS 5° April 18 greatest elongation but barely scrapes the horizon December 10, 30 minutes after sunset at its August 16 best. The plan- Looking southwest et’s top morning apparition comes in late September when Look for Mercury low in the southwestern sky after sunset during the first half of December. It reachesCIR-PB-618329_29 peak visibility at greatest elongation on the it climbs about 10° high in the 10th, when the planet lies about 25° to the lower right of brilliant Venus. east a half-hour before sunrise.

www.Astronomy.com 13 2017 preview Looking ahead to next year...

The long wait is over. On August 21, 2017, the United States will be at the center of the astronomical universe when the Moon’s dark umbral shadow creates the country’s first total solar eclipse in 26 years. But that tells only half the story. The July 11, 1991, eclipse touched just Hawaii before heading to Mex- ico and then south to Brazil. The last time the U.S. Mainland saw totality was February 26, 1979. But the decades-long drought will be long forgotten by the time the Moon’s umbra sweeps coast to coast on August 21. The track The Sun’s ghostly corona and fiery-red prominences show up beautifully first hits land in Oregon. (Coincidentally, that state’s capital, Salem, during a total solar eclipse. Patrick Martinez is in the path of totality this year as it was in 1979.) From there, the shadow speeds southeast across the country in approximately 90 CANADA minutes until exiting on the South Carolina shore. Totality’s great- Portland est duration occurs in southern Illinois, where the Moon com- Path of totality Salem pletely hides the Sun’s bright disk for 2 minutes and 40 seconds. Casper Still, anyone on the center line will see at least 119 seconds of total- Idaho Falls Lincoln Columbia ity. Observers across the rest of North America can see a partial St. Louis eclipse, but let’s be real — if you have any interest in astronomy, Grand Island Carbondale Kansas City Hopkinsville you need to be in the path of totality on August 21. Greenville Greatest eclipse Two other eclipses of note occur in 2017, though both pale Columbia Nashville in comparison. An annular solar eclipse — in which the Moon appears a bit too small to cover our star, leaving a ring of sunlight visible — arrives February 26. The path crosses southern South 0 300 miles America and the Atlantic Ocean before ending in southern Africa. MEXICO And Earth’s shadow partially hides the Moon on August 7. It is the 0 400 km first partial or total lunar eclipse in 23 months. The path of the first total solar eclipse to touch the U.S. Mainland in 38 years Observers with a penchant for planets have three to keep them cuts across the country from Oregon to South Carolina on August 21, 2017. satisfied. Venus puts on a marvelous show on evenings in early 2017. At greatest elongation January 12, it shines brilliantly in the southwest as darkness falls and doesn’t set until four hours after the Sun. Jupiter and Saturn also put on great shows in 2017. Giant Jupiter reaches peak visibility in April while ringed Saturn follows two months later. Saturn in particular stands out. At opposition June 15, its ring system tilts 26.6° to our line of sight — the steepest angle at any opposition since 2002. The large tilt will afford tele- scope owners exquisite views of ring structure. The 2017 meteor calendar also looks a bit brighter than it did in 2016. Two of the year’s most prolific showers — January’s Quad­ rantids and December’s Geminids — occur within a few days of The Moon dips into Earth’s dark umbral shadow for the first time New Moon, as do the reliable Orionids of October and Leonids in nearly two years on August 7, of November. Of the best showers, only the Perseids (which peak 2017. Steve Gabino under a waning gibbous Moon) fare poorly.

14 Sky Guide 2016 NASA’s Juno spacecraft will reach giant Jupiter on July 4, 2016, commencing a nearly two-year mission to study the planet’s interior. NASA/JPL-Caltech

A year of exploration

While 2015 saw New Horizons fly past Pluto, completing minor atmospheric constituents possibly linked to current geologic the initial reconnaissance of the solar system’s nine traditional and biologic activity. The orbiter also will deploy a lander, named planets, 2016 will see the first dedicated mission to Jupiter in more Schiaparelli, to test ESA’s ability to reach the martian surface. than a decade. NASA’s Juno spacecraft arrives at the giant planet These new probes join seven others currently operating on July 4 following a five-year trek. Although Juno has a camera and and above the Red Planet. And readers should expect plenty more should take some incredible close-up images, the mission’s main from the flotilla of spacecraft scattered throughout the solar sys- goal is to study the gas giant’s interior by mapping the planet’s mag- tem. NASA’s Cassini craft will continue to study Saturn and its netic and gravity fields. The probe will pass within a few thousand rings and moons as it heads toward mission completion in 2017. miles of the cloud tops during each of its 32 orbits. Dawn will maintain its orbital reconnaissance of dwarf planet NASA also plans to target its favorite subject — Mars — in Ceres for at least the first few months of 2016. ESA’s Rosetta probe 2016. Scheduled to launch in March and land in September, will scrutinize Comet 67P/Churyumov-Gerasimenko until Sep- InSight will measure the heat flowing through the planet’s surface tember. And New Horizons, which accomplished its Pluto flyby in and search for seismic activity. The craft’s design is based on that July 2015, will return new data through most of the coming year. of the successful Phoenix lander from 2008. The European Space The rapid pace of planetary exploration shows no signs of Agency (ESA), in cooperation with Russia’s Roscosmos, also plans ­abating in 2016. You can count on seeing all the new results in a Mars mission in 2016. The ExoMars Trace Gas Orbiter will study the pages of Astronomy.

NASA’s Dawn spacecraft will continue to study Ceres, and this intriguing conical mountain, during early 2016. NASA/JPL-Caltech/ UCLA/MPS/DLR/IDA

NASA’s InSight mission will probe Mars for signs of ongoing internal activity once it arrives in September 2016. NASA/JPL-Caltech

www.Astronomy.com 15 CELESTRON ASY Special Booklet • 11/08/2015 • 4C • 1 PG

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