2020• by Martin Ratcliffe and Richard Talcott •

Sky Guide

2020• BY MARTIN RATCLIFFE AND RICHARD TALCOTT •

contents 2 Jan. 2020 Venus points the way to Neptune 3 Feb. 2020 Lovely Luna conceals Mars Mars returns to brilliance in 2020 as it climbs high into the sky for 4 March 2020 A series of splendid conjunctions Northern Hemisphere observers. 5 April 2020 Dazzling Venus meets the Pleiades NASA/JPL/USGS 6 May 2020 Watch a giant star wax and wane 7 June 2020 Mercury glows in evening twilight Martin Ratcliffe provides profes- 8 Jupiter and Saturn rule the night sional planetarium development July 2020 for Sky-Skan, Inc. Richard Talcott 9 Aug. 2020 A dwarf planet glows brightly is a senior editor of Astronomy. 10 Sept. 2020 An ice giant in the celestial sea 11 Oct. 2020 The Red Planet climbs high in the sky A supplement to 12 Nov. 2020 Dark skies for autumn meteors Astronomy magazine 13 Dec. 2020 Totality returns to South America 14 2021 Preview Looking ahead to next year … 618372 2020 Jan S M T W T F S Venus points the 1 3 4 5 6 7 8 9 11 12 13 14 15 16 18 way to Neptune 19 20 21 22 23 25 26 27 28 29 30 31 t’s rare to see Venus, the planet whose orbit brings Planetary conjunctions in 2020 it closest to Earth, line up Nearer planet Farther planet Date Separation with Neptune, the most Venus Neptune Jan. 27 0.1° 4 Quadrantid meteor distant major planet. Yet shower peaks Venus Uranus March 9 2.4° Ithey do just that January 27. Mars Jupiter March 20 0.7° The Moon passes That evening, the two worlds 5° south of Uranus, Mars Saturn March 31 0.9° appear closer to each other 1 p.m. EST Venus Mercury May 22 0.9° than they have at any point 10 Mercury is in supe- Mars Neptune June 12 1.7° since January 1984. Any tele- rior conjunction, Jupiter Saturn Dec. 21 0.1° 10 a.m. EST scope will show the pair in a Penumbral lunar single field of view. eclipse, 2 p.m. EST The two certainly make an Although Venus and Neptune on January 27. The 13 Pluto is in conjunc- odd couple. Although a thick Neptune cross paths roughly two lie 40° east of the Sun and tion with the Sun, atmosphere cloaks both plan- once a year, they rarely come stand some 20° high in the 8 a.m. EST ets, the similarities end there. as close as they do this month. west-southwest once darkness Saturn is in con- Venus is an Earth-sized world Part of the reason is that falls. You can’t miss Venus, junction with the that lies just 67 million miles Venus’ orbit tilts 3.4° to the which dazzles at magnitude Sun, 10 a.m. EST from the Sun. Baked by our plane of Earth’s orbit around –4.1. You’ll likely need a tele- Dwarf planet Ceres star’s intense heat, the rocky the Sun while Neptune’s tilts scope to spot magnitude 7.9 is in conjunction with the Sun, planet’s surface temperature only 1.8°. So, more often than Neptune in the brighter plan- 1 p.m. EST soars above 850 degrees not, when the two planets pass et’s glare. A slim crescent 16 Mars passes 5° Fahrenheit, hot enough to melt near each other, they miss by Moon adds to the naked-eye north of Antares, lead. Neptune is an ice giant at least 1°. Complicating mat- scene from its perch 7° below 11 p.m. EST four times Venus’ diameter ters further, the planets’ con- the planetary pair. 20 The Moon passes that lurks on the frigid edge of junctions often occur when The conjunction arrives 2° north of Mars, our solar system a staggering they lie too close to the Sun precisely at 2 p.m. EST. By the 2 p.m. EST 2.8 billion miles from the Sun. to observe. time night falls in North 22 The Moon passes Its atmospheric temperature That’s what makes this America a few hours later, 0.4° south of Jupiter, 10 p.m. EST dips to –330 F, nearly cold month’s event so appealing. Neptune appears 12' due west enough to freeze nitrogen. Venus passes just 5' south of of its companion. The 4th- 27 Venus passes 0.08° south of Neptune, magnitude star Phi (ϕ) Aquarii 2 p.m. EST N stands a nearly equal distance 28 The Moon passes to Venus’ east-northeast. A 4° south of Neptune, telescope shows Venus’ disk, 1 a.m. EST 96 which appears 15" across and The Moon passes 29 Path of Venus three-quarters lit. Neptune’s 4° south of Venus, disk spans 2.2" and looks fully 2 a.m. EST 28 φ illuminated. 31 The Moon passes E 27 Neptune If you miss this event, 5° south of Uranus, URIUS 10 p.m. EST Venus and Neptune have two 26 more close conjunctions in the coming years. In April 2022, Jan 25 they approach within 0.5' of 83 χ each other, and in February 2023, they’ll appear 1' apart. 0.5° Unfortunately, the planets will Venus slides within 0.1° of Neptune on January 27, the closest approach of lie significantly lower in the the two planets in 36 years.ASY-SG0120_20 ALL ILLUSTRATIONS: ASTRONOMY: ROEN KELLY sky both times.

2 Sky Guide 2020 2020 Feb Lovely Luna S M T W T F S

2 3 4 5 6 7 8 conceals Mars 10 11 12 13 14 16 17 18 19 20 21 22 24 25 26 27 28 29 ars crosses West Coast, where Mars has the border already disappeared by the between time the two objects rise, Ophiuchus observers can still watch the the Serpent- planet reappear from behind 10 Mercury is at greatest eastern bearer and Sagittarius the the Moon’s dark limb. M elongation (18°), Archer on February 11, setting For example, Mars disap- 9 a.m. EST up a series of superb encoun- pears at 6:05 a.m. CST in 18 The Moon passes ters for early risers. On the Chicago and at 5:47 a.m. CST 0.8° north of Mars, 16th, the Red Planet forms an in Houston. In Denver, the 8 a.m. EST equilateral triangle with the disappearance occurs at 19 The Moon passes Lagoon Nebula (M8) and 4:40 a.m. MST with the 0.9° south of Jupiter, Trifid Nebula (M20). Mars objects 9° high in a dark sky. 3 p.m. EST shines at magnitude 1.2 and In San Francisco, Mars returns 20 The Moon passes adds an elegant focus to to view at 4:29 a.m. PST, while 0.7° south of Pluto, 3 a.m. EST Sagittarius’ rich star fields. the same event occurs one The Moon passes The planet’s eastward minute earlier in Los Angeles. 1.7° south of Saturn, motion against the stellar According to David Mars appeared at the limb of a 9 a.m. EST backdrop carries it midway Dunham of the International waxing crescent Moon on July 27, 25 Mercury is in infe- between the Lagoon and 2006, moments before the Moon Occultation Timing rior conjunction, Trifid on February 17, but occulted the planet. TUNÇ TEZEL Association (IOTA), Mars 9 p.m. EST that’s nothing compared with itself occults a faint star later 27 The Moon passes the show awaiting observers Midwest. Although it won’t be this year. On September 24, 6° south of Venus, on the 18th. That morning, visible along the East Coast the magnitude –2.4 planet 7 a.m. EST the waning crescent Moon because it happens after sun- passes in front of a 10th- 28 The Moon passes slides in front of Mars for rise, observers there can still magnitude star in eastern 4° south of Uranus, 7 a.m. EST observers across most of see a stunningly close con- Pisces. This will be a challeng- North America. junction between the two ing observation because of the Although you can watch objects before dawn. On the huge brightness difference. this wonderful occultation with your naked eyes, binoculars or a telescope greatly OPIUCUS enhance the view. Optical aid lets you see Mars slowly fade Moon Moon Phases out as the Moon’s bright limb devours its prey. Depending First Quarter Mars on your location, it can take Full Moon the Moon up to 15 seconds to fully engulf the planet’s Last Quarter 5.2"-diameter disk. New Moon

The occultation’s timing SCORPIUS depends on where you live. Jupiter SIRIUS Events that can be viewed Not only does the event occur with the naked eye 5° earlier the farther west you Events that can be viewed live, but changes in latitude with binoculars February 18, 5:00 A.M. CST also affect the timing. The Looking southeast Events that can be viewed event occurs in darkness with a telescope in western North America The waning crescent Moon glides in front of the Red Planet before dawn and during twilight in the February 18. This view capturesASY-SG0120_21 the scene just before the event starts.

www.Astronomy.com 3 2020 March A series of splendid S M T W T F S 1 3 4 5 6 7 8 10 11 12 13 14 conjunctions 15 17 18 19 20 21 22 23 25 26 27 28 29 30 31 arch’s pre- dawn sky holds three planetary 8 Neptune is in con- gems. Mars, junction with the Jupiter, and Saturn string out Sun, 8 a.m. EDT M like pearls set against the back- 9 Venus passes 2° north of Uranus, drop of Sagittarius the Archer. 11 a.m. EDT The beautiful scene appears 18 The Moon passes above the southeastern hori- 0.7° south of Mars, zon on every clear morning 4 a.m. EDT this month. The Moon passes Mars treks eastward during 1.5° south of Jupiter, March and passes close to both 6 a.m. EDT Jupiter and Saturn. Each con- The Moon passes junction would attract attention 0.9° south of Pluto, on its own, so having two in the 11 a.m. EDT A brilliant Moon joined Mars, Jupiter, and Saturn on March 8, 2018. Jupiter same month is a treat — and appears to Luna’s right, with Mars and Saturn to the left. RYAN IMPERIO The Moon passes 2° south of Saturn, a rare one at that. Jupiter and 8 p.m. EDT Saturn appear near each other Jupiter is the brightest of the Jupiter’s vicinity March 18, 19 Equinox (northern at roughly 20-year intervals. trio, gleaming at magnitude when a waning crescent Moon spring/southern The last time all three planets –2.0, with Saturn next at mag- joins the pair. All three lie autumn begins), came this close was April 2000. nitude 0.7, and Mars slightly within a 2.5°-wide circle, with midnight EDT As March opens, 19° fainter at magnitude 1.1. the two planets 1.3° apart. 20 Mars passes 0.7° separate the three worlds. Mars Because Mars lies closer to Mars and Jupiter appear south of Jupiter, rises first, at around 3:30 a.m. Earth than Jupiter and Saturn, closest March 20. The rust- 2 a.m. EDT local time. Jupiter follows about it moves eastward more colored Mars then stands 0.7° 21 The Moon passes 4° south of Mercury, 40 minutes later, and Saturn quickly and soon catches up south of the slightly yellow- 2 p.m. EDT appears a half-hour after that. with the other two. It reaches ish Jupiter. A telescope at low power will capture both planets 23 Mercury is at greatest western in the same field. Even though elongation (28°), Altair Jupiter lies much farther from 10 p.m. EDT Earth, its apparent diameter of 24 Venus is at greatest 36" towers over Mars’ 6" girth. eastern elongation Saturn lies 7° — about one bin- (46°), 6 p.m. EDT UIL ocular field — east of the pair. 26 The Moon passes Mars continues moving 4° south of Uranus, 5 p.m. EDT eastward, reaching a point Jupiter approximately midway between 28 The Moon passes 7° south of Venus, Saturn the other two planets on the 7 a.m. EDT Mars 26th. The month’s final morn- SIRIUS Mars passes 0.9° ing sees Mars passing 0.9° south 31 CPRICORUS south of Saturn, 10° of Saturn against the backdrop 7 a.m. EDT of western Capricornus. Mars has brightened to magnitude March 26, 1 hour before sunrise 0.8, almost matching Saturn’s Looking southeast luster. They present a stunning Mars appears midway between ASY-SG0120_22 Jupiter and Saturn the morning of sight before dawn, with Jupiter March 26, when all three planets lie within 7° of one another. located 6° to their west.

4 Sky Guide 2020 2020 Dazzling Venus April S M T W T F S 2 3 4 meets the Pleiades 5 6 8 9 10 11 12 13 15 16 17 18 19 20 21 23 24 25 26 27 28 29 enus dominates the western evening sky from the beginning of 2020 until late 2 Asteroid Juno is at opposition, May. But it shines brightest, at V 4 p.m. EDT magnitude –4.7, during April’s 3 Mercury passes 1.4° final week. Venus spends the south of Neptune, entire month among the back- 11 a.m. EDT ground delights of Taurus the 14 The Moon passes Bull. Its best encounter comes 1.2° south of Pluto, in early April when it slips 6 p.m. EDT through the southern part of The Moon passes 2° south of Jupiter, the Pleiades star cluster (M45). Brilliant Venus shines next to the dipper-shaped star cluster known as the 7 p.m. EDT On the evening of April 3, Pleiades. The striking objects meet again in early April. JOHN CHUMACK Venus stands 15' — half the 15 The Moon passes 2° south of Saturn, Full Moon’s diameter — south Procyon 5 a.m. EDT of magnitude 2.9 Alcyone, the 16 The Moon passes cluster’s luminary. The planet EMII 2° south of Mars, shines 1,000 times brighter 1 a.m. EDT than the star. From Hawaii, URI Capella 17 Venus passes 10° where darkness falls a few Betelgeuse north of Aldebaran, hours later than on the main- 4 p.m. EDT Venus land, Venus appears closer to ORIO 19 The Moon passes magnitude 3.6 Atlas, the clus- Aldebaran 4° south of Neptune, ter’s second-brightest star. At PERSEUS 3 a.m. EDT their closest, just 6' separate Rigel Pleiades 22 Lyrid meteor shower peaks the two objects. URUS The scene looks spectacular 10° 26 Uranus is in conjunction with the whether you view it with your Sun, 5 a.m. EDT naked eyes or with optical aid. Mid-April, 1 hour after sunset The Moon passes You’ll need a scope to resolve Looking west 6° south of Venus, Venus’ disk, which spans 27" 11 a.m. EDT and appears 45 percent lit. Venus dominates the western sky after sunset for the first half of 2020, but it appears most spectacular as it crosses Taurus during April. 27 Venus is at Venus remains within a few greatest brilliancy, degrees of M45 for several when it lies 46° east of our star diminishing altitude, it still 2 p.m. EDT days before and after April 3, and climbs 32° high in the west stands 25° high an hour after and you’ll want to revisit the an hour after sundown. That the Sun goes down on the 27th. scene every clear evening. evening, a telescope shows the Venus disappears for about Although April ranks as planet’s 24"-diameter disk and two weeks around its June 3 Venus’ finest month, the rest nearly half-lit phase. solar conjunction, before of 2020 isn’t shabby. The planet Venus continues to grow reemerging in the morning begins the year in Capricornus larger while its crescent wanes sky in mid-June. The planet shining at magnitude –4.0. It for the next two months. At reaches greatest western elon- then stands some 15° above greatest brilliancy April 27, gation August 12 and appears the southwestern horizon an it sports a disk 37" across nearly as high as it did in late hour after sunset. Its distance and barely one-quarter lit. March. Venus remains a stun- from the Sun grows until Although its rising telescopic ning sight before dawn greatest elongation March 24, appeal is tempered by its through the end of the year.

www.Astronomy.com 5 2020 May Watch a giant star S M T W T F S 1 2 3 4 5 6 8 9 wax and wane 10 11 12 13 15 16 17 18 19 20 21 23 24 25 26 27 28 30 ne of the can be seen in galaxies 31 sky’s most tens of millions of light- important years from Earth. stars You can track 4 Mercury is in supe- climbs Delta’s variations with rior conjunction, high in the northeast your own eyes. The star 6 p.m. EDT O on May nights. Glowing lies midway between 5 Eta Aquariid meteor shower at 4th magnitude, Delta Cygnus’ brightest star, peaks (δ) Cephei resides in Deneb, and the familiar 12 The Moon passes the southeastern corner W shape of the constel- 2° south of Jupiter, of Cepheus the King. lation Cassiopeia. Delta 6 a.m. EDT It’s a yellow supergiant belongs to a tight tri- The Moon passes star whose light output angle of 4th-magnitude 3° south of Saturn, varies in response to stars with Zeta (ζ) and 2 p.m. EDT regular pulsations in Epsilon (ε) Cephei. 14 The Moon passes its outer layers. These two companions 3° south of Mars, British amateur make good comparison 10 p.m. EDT astronomer John stars because Zeta 16 The Moon passes 4° south of Neptune, Goodricke first noticed shines at magnitude 11 a.m. EDT Delta’s unusual behav- 3.6 and Epsilon at 17 Mercury passes 7° ior in 1784. He found magnitude 4.2. north of Aldebaran, the star varied from To find Delta’s mag- 5 a.m. EDT Delta Cephei lurks in southeastern magnitude 3.5 to 4.4 Cepheus, a constellation whose nitude, mentally place 20 The Moon passes and back again over a period of shape resembles a child’s drawing it on a scale of one to five 4° south of Uranus, 5.366 days. In the years since, of a house. TONY HALLAS between the brightness of Zeta noon EDT observers have discovered and Epsilon. At first this may 22 Mercury passes 0.9° many other stars showing simi- brightness with the intrinsic seem unusual, but you’ll soon south of Venus, lar patterns, though the periods brightness derived from the gain experience. This method 4 a.m. EDT range from a few days up to relation. Because all Cepheids will gauge Delta’s brightness to 23 The Moon passes 4° south of Venus, about 100 days. They became are luminous supergiants, they within 0.2 magnitude. 11 p.m. EDT known as Cepheid variables, 24 The Moon passes 3° after the prototype in Cepheus. N south of Mercury, A huge breakthrough came α 7 a.m. EDT in 1912 when American astron- η 26 36 omer Henrietta Swan Leavitt CEPEUS discovered 25 Cepheids in the Small Magellanic Cloud, one of the Milky Way’s many satellite ν δ 36 ζ 45 galaxies. She found that the E ε brighter a Cepheid appears, the 42 longer it takes to go from maximum light to minimum light β and back. Once astronomers 46 calibrated this so-called period- LCER luminosity relation, they could calculate the distance to any 2° of these stars. They simply had to measure the star’s period Delta (δ) Cephei changes ASY-SG0120_24brightness by 0.9 magnitude every 5.4 days. and compare the observed (Numbers are magnitudes with their decimal points omitted.)

6 Sky Guide 2020 2020 Mercury glows in June S M T W T F S 1 2 3 4 6 evening twilight 7 8 9 10 11 12 14 15 16 17 18 19 20 22 23 24 25 26 27 29 30 ercury appears highest in the evening sky for 2020 3 Venus is in inferior conjunction, during June’s first week. The M 2 p.m. EDT innermost planet reaches 4 Mercury is at greatest elongation on the 4th, greatest eastern when it lies 24° east of the Sun elongation (24°), and appears 10° high in the 9 a.m. EDT west-northwest 45 minutes 5 Penumbral lunar after sunset. Mercury glows eclipse, 3 p.m. EDT at magnitude 0.5 and should Although 8 The Moon passes show up nicely to the naked Mercury 2° south of Jupiter, appears 1 p.m. EDT eye in the gathering darkness. lackluster It slightly outshines Castor through telescopes The Moon passes 3° south of Saturn, and Pollux, the two brightest on Earth, the MESSENGER 45 minutes 10 p.m. EDT stars in the constellation spacecraft revealed signs of after sunset while geologic activity. NASA/JHUAPL/CIW 12 Mars passes 1.7° Gemini, which stand 15° Venus lies to its lower right south of Neptune, higher in the twilight. make a delightful pair in the and is just 5° high. Magnitude 8 a.m. EDT Mercury shines brighter twilight sky. –0.4 Mercury nestles midway The Moon passes 4° and lies nearly as high in late A slender crescent Moon between the two. south of Neptune, May, so plan to start tracking adds to the beauty of the eve- If you want to view 7 p.m. EDT it then. You can use Venus as ning scene May 23. Look for Mercury through a telescope, The Moon passes a guide. On the 21st, the bril- Luna 4° to Venus’ lower left the time around greatest elon- 3° south of Mars, liant planet shines at magni- and Mercury the same distance gation is best. On June 4, the 8 p.m. EDT tude –4.3 and lies 9° high to the brighter planet’s upper planet’s disk appears 8" across 16 The Moon passes 4° south of Uranus, 45 minutes after sundown. left. The following night, a and 36 percent lit. Mercury 10 p.m. EDT Mercury glows at magnitude slightly fatter crescent Moon grows larger and shows a skin- 19 The Moon passes –0.7 just 1° below it. The two stands 13° above the horizon nier crescent in the week that 0.7° north of Venus, follows, though it also becomes 5 a.m. EDT Pollux harder to see as it dims and Castor 20 Solstice (northern sinks closer to the horizon. summer/southern Mercury makes two other winter begins), evening appearances this year. 6 p.m. EDT It climbs nearly as high at its 21 Annular solar February 10 greatest eastern eclipse, 3 a.m. EDT EMII elongation, though it likely 30 Mercury is in inferior conjunction, will be lost in twilight at its Mercury 11 p.m. EDT URI October 1 peak. For those who prefer viewing Mercury in the quiet hours before dawn, the 5° planet hits its high point at greatest western elongation November 10. It appears June 4, 45 minutes after sunset slightly lower on mornings Looking west-northwest around its July 22 peak and The best time to view MercuryASY-SG0120_25 this year comes when it climbs highest in barely scrapes the horizon at evening twilight around its June 4 greatest eastern elongation. its March 23 appearance.

www.Astronomy.com 7 2020 July Jupiter and Saturn S M T W T F S 1 2 3 4 6 7 8 9 10 11 rule the night 13 14 15 16 17 18 19 21 22 23 24 25 26 28 29 30 31 he solar system’s two largest planets reach opposition Altair and peak visibility OPIUCUS 5 Penumbral lunar UIL within a week of PESUS eclipse, 1 a.m. EDT Teach other this month. Jupiter The Moon passes and Saturn, which haven’t been 1.9° south of Jupiter, Jupiter 6 p.m. EDT this close to each other in 20 SIRIUS years, form a marvelous pair URIUS Saturn The Moon passes 6 CPRICORUS 2° south of Saturn, that remains on view all night. SCORPIUS 5 a.m. EDT Jupiter spends most of 2020 10 The Moon passes 4° in Sagittarius. The planet’s south of Neptune, normal eastward motion rela- 3 a.m. EDT tive to the starry backdrop Fomalhaut Venus is at comes to a halt in mid-May 10° greatest brilliancy, at a point 5° west of Saturn. 4 a.m. EDT Jupiter then heads westward, Mid-July, midnight 11 The Moon passes or retrograde, as it approaches Looking south-southeast 2° south of Mars, 4 p.m. EDT its July 14 opposition. The gas giant shines brightest, at mag- Gas giants Jupiter and Saturn come to opposition within six days of each 12 Venus passes 1.0° other this month, when a mereASY-SG0120_26 7° separate the two. north of Aldebaran, nitude –2.8, at opposition. 3 a.m. EDT Saturn also begins its retro- Asteroid Pallas grade loop in mid-May. It magnitude 0.1, just 7 percent displays two parallel dark belts is at opposition, crosses the border from as bright as Jupiter. that sandwich a brighter zone 10 p.m. EDT Capricornus into Sagittarius Both planets look stunning coinciding with the equator. 14 Jupiter is at opposi- on July 3 ahead of its July 20 through a telescope. Jupiter’s Saturn excels because of its tion, 4 a.m. EDT opposition. At its peak, the disk spans 48" at opposition. rings. At opposition, the plan- The Moon passes ringed planet shines at Its dynamic atmosphere et’s disk measures 18" across 4° south of Uranus, while the rings span 42" and 8 a.m. EDT tilt 22° to our line of sight. 15 Pluto is at opposi- Both planets also host tion, 3 p.m. EDT several moons visible through 17 The Moon passes small scopes. Jupiter boasts 3° north of Venus, 3 a.m. EDT four — Io, Europa, Ganymede, and Callisto — while Saturn 18 The Moon passes 4° north of Mercury, claims 8th-magnitude midnight EDT Titan and a quartet of 10th- 20 Saturn is at opposi- magnitude moons. tion, 6 p.m. EDT Both planets end their ret- 22 Mercury is at rograde loops in September, greatest western when 8° separate them. As elongation (20°), they head eastward, Jupiter 11 a.m. EDT moves faster and catches up with its neighbor. The two meet December 21 when Jupiter passes 0.1° south of Saturn. The stunning pair The brightly colored bands in Jupiter’s atmosphere stand out when it looms stands 12° high in the south- large, as it does at opposition July 14. NASA/ESA/A. SIMON (GSFC)/M.H. WANG (UC, BERKELEY) west an hour after sunset.

8 Sky Guide 2020 2020 A dwarf planet glows Aug S M T W T F S 1 brightly 2 4 5 6 7 8 9 10 12 13 14 15 16 17 19 20 21 22 23 24 26 27 28 29 n January 1, The Dawn spacecraft 1801, Italian captured Ceres, with 30 31 Occator Crater at the astronomer center, from 240 miles Giuseppe away. NASA/JPL-CALTECH/ Piazzi UCLA/MPS/DLR/IDA 1 The Moon passes 1.5° south of Jupiter, discovered an object cir- O 8 p.m. EDT cling the Sun between the follows a westerly 2 Mercury passes 7° orbits of Mars and Jupiter. course, dipping south of Pollux, Initially thought to be a new into Piscis Austrinus 2 a.m. EDT planet, Ceres was reclassified during the first half The Moon passes as an asteroid later in the 19th of September before 1.1° south of Pluto, century before being partially returning to Aquarius in mid- 2 a.m. EDT resurrected as a dwarf planet The asteroid passes just 5' east October. Along the way, it The Moon passes in 2006. This 584-mile-wide of the star on the 4th and 9' passes 16' south of 6th magni- 2° south of Saturn, object reaches opposition south of the star on the 5th. tude 49 Aqr on October 11. A 9 a.m. EDT August 28. No other object in the vicinity week later, it stands a similar 6 The Moon passes 4° south of Neptune, Although Ceres glows glows brighter than 9th mag- distance east of the interact- 11 a.m. EDT brightest at opposition, it’s nitude, so you shouldn’t have ing Atoms for Peace Galaxy 9 The Moon passes easier to find in early August any trouble identifying Ceres. (NGC 7252). Astroimagers 0.8° south of Mars, when it slides past 88 Aquarii, Once you’ve found Ceres, will want to capture the mag- 4 a.m. EDT a 4th-magnitude star in far you can track it through the nitude 8.5 dwarf planet next 10 The Moon passes southern Aquarius. The mag- end of August as it wanders to this peculiar system. 4° south of Uranus, nitude 8.0 dwarf planet will be into a sparser region near the A better chance to shoot 5 p.m. EDT simple to spot through bin- Aquarius-Piscis Austrinus Ceres near a bright deep- 12 Perseid meteor oculars or a small telescope. border. The dwarf planet sky object comes when it shower peaks The trickiest part is finding brightens to magnitude 7.7 by cruises within 1° of the Helix Venus is at greatest 88 Aqr. Fortunately, a brighter August 18 and remains this Nebula (NGC 7293) between western elongation (46°), 8 p.m. EDT star helps point the way. bright through month’s end. November 18 and 22. Although First-magnitude Fomalhaut On the 22nd, you can find it the asteroid has faded to mag- 15 The Moon passes 4° north of Venus, rises around 11 p.m. local 6° due north of Fomalhaut. nitude 8.9, it remains within 9 a.m. EDT daylight time in early August After opposition, Ceres easy reach of a small telescope. 17 Mercury is in supe- and climbs highest in the rior conjunction, south around 3 a.m. Center N URIUS 11 a.m. EDT 98 88 υ Fomalhaut in your binoculars, 99 Dwarf planet Ceres Aug 1 28 then scan 6° north and slightly 6 is at opposition, Path of Ceres 8 a.m. EDT east to find three similarly 89 11 bright stars: 86, 89, and 88 Aqr. 16 The Moon passes 21 Our guide star is the slightly 86 1.4° south of Jupiter, 26 10 p.m. EDT brighter, northernmost mem- 31 ber of this trio. E 29 The Moon passes 1.2° south of Pluto, Ceres appears within 1° of 7 a.m. EDT 88 Aqr during August’s first SCULPOR ε ζ The Moon passes 10 days. On the 1st, the dwarf 2° south of Saturn, planet lies 32' — about the PISCIS 1 p.m. EDT diameter of a Full Moon — USRIUS east-northeast of the star. Ceres 1° moves southwest from night Fomalhaut to night and seems to be on a The dwarf planet Ceres glides through southern Aquarius during August, collision course with 88 Aqr. about one binocular field ASY-SG0120_27north of 1st-magnitude Fomalhaut.

www.Astronomy.com 9 2020 Sept An ice giant in the S M T W T F S 1 3 4 5 6 7 8 9 11 12 celestial sea 13 14 15 16 18 19 20 21 22 24 25 26 27 28 29 30 he solar system hosts eight major planets, but none is as hard to see as 1 Venus passes 9° Neptune. It’s the south of Pollux, only planet that’s never bright 1 p.m. EDT T enough to see with the naked 2 The Moon passes 4° south of Neptune, eye. Still, binoculars or a small 5 p.m. EDT telescope capture its light quite 6 The Moon passes easily. And there’s no better 0.03° north of Mars, time to hunt it down than in 1 a.m. EDT September, when it reaches The Moon passes opposition and peak visibility. 3° south of Uranus, Neptune resides among the midnight EDT background stars of Aquarius 11 Neptune is at the Water-bearer. Although it opposition, has called Aquarius home 4 p.m. EDT Amateur telescopes show Neptune’s small disk and blue-gray color, but since 2011, it has now moved don’t expect to see the level of detail Voyager 2 captured in 1989. NASA/JPL 14 The Moon passes 4° north of Venus, into the far eastern part of this 1 a.m. EDT constellation. To find it, first N locate the 4th-magnitude star 18 The Moon passes 6° PISCES north of Mercury, Phi (ϕ) Aquarii. Neptune stays 6 p.m. EDT within 2.5° of Phi all month. 22 Mercury passes The ice giant planet reaches 0.3° north of Spica, opposition September 11, when 5 a.m. EDT it lies opposite the Sun in our E Neptune Equinox (northern sky and thus remains visible all 96 autumn/southern spring begins), night. A planet typically shines 10 a.m. EDT brightest at opposition, but in φ Neptune’s case, it sustains its 25 The Moon passes URIUS 1.6° south of Jupiter, magnitude 7.8 glow from mid- χ 3 a.m. EDT July to early November. 1° ψ2 The Moon passes On September 11, Neptune ψ3 1 2° south of Saturn, forms an equilateral triangle ψ 5 p.m. EDT with two brighter stars — The constellation Aquarius hosts Neptune again this year. At opposition 29 The Moon passes 4° 5.6-magnitude 96 Aqr and a September 11, the ice giant liesASY-SG0120_28 2.1° east-northeast of Phi (ϕ) Aquarii. south of Neptune, 6.2-magnitude field star — 10 p.m. EDT located 1.5° east of Phi. The Neptune, you’ll need a tele- field to its east. Wait a couple planet lies east of a line joining scope to see it as more than a of nights, and you can track these suns and some 0.7° away point of light. At opposition, down its magnitude 5.7 glow from each. Neptune’s westward the planet shows a disk that against the backdrop of south- motion after opposition carries spans 2.4" and has a subtle ern Aries, some 10° south- it directly between these stars blue-gray hue. southeast of 2nd-magnitude during October’s first week. Neptune’s sister world, Hamal, the Ram’s brightest star. The ice giant comes within 0.7° Uranus, reaches opposition Although Uranus shows up of Phi when it wraps up its ret- October 31. You might have a easily through binoculars, rograde loop in late November. hard time spotting it that night, you’ll need a telescope to see Although binoculars gather however, because a Halloween its 3.8"-diameter disk and dis- enough light to show you Full Moon lies one binocular tinctive blue-green color.

10 Sky Guide 2020 2020 The Red Planet Oct S M T W T F S 2 3 climbs high in the sky 4 5 6 7 8 10 11 12 13 14 15 17 18 19 20 21 22 24 25 26 27 28 29 30 ars reaches opposition N at roughly ο 26-month PISCES intervals, ζ 1 Mercury is at ε greatest eastern but some of these appearances M Sept 16 elongation (26°), are much better than others. Oct 1 μ noon EDT October brings one of the E 16 31 2 Venus passes 0.09° best. At opposition on the ν Path of Mars Nov south of Regulus, 15 13th, the Red Planet shines at 8 p.m. EDT Mars reaches opposition magnitude –2.6 and shows a ξ October 13 The Moon passes disk 22.3" in diameter. (It 0.7° south of Mars, appears 0.3" larger when it 11 p.m. EDT 4 The Moon passes comes closest to Earth a CEUS week earlier.) 1° 3° south of Uranus, 5 a.m. EDT Although Mars came Mars is at opposi- slightly closer to Earth and The Red Planet reaches its peak at opposition in October, when it resides 13 among the background stars ofASY-SG0120_29 eastern Pisces the Fish. tion, 7 p.m. EDT shone a bit brighter at its pre- The Moon passes vious opposition in July 2018, 4° north of Venus, the view this year should be Jupiter on March 20, 0.9° 15" on August 4, and 20" on 8 p.m. EDT even better for those in the south of Saturn on March 31, September 8. These changes 17 The Moon passes 7° Northern Hemisphere. In and 1.7° south of Neptune on finally become visible to north of Mercury, 2018, Mars lurked in southern June 12. evening observers once the 3 p.m. EDT Capricornus at a declination The Red Planet bright- planet rises before midnight 21 Orionid meteor of –26°. This meant that for an ens steadily in the lead-up local daylight time starting shower peaks observer at 40° north latitude, to opposition. It reaches in mid-July. 22 The Moon passes the planet climbed no higher magnitude 1.0 on March 8, By the time of opposition, 2° south of Jupiter, 1 p.m. EDT than 24°. At opposition this magnitude 0.0 on May 28, Mars surpasses Jupiter as the year, Mars lies in Pisces at a magnitude –1.0 on June 26, brightest point of light in the The Moon passes 3° south of Saturn, declination of 5° and climbs and magnitude –2.0 on evening sky. Only Venus midnight EDT 55° above the horizon at its September 7. This rapid appears brighter once it rises 25 Mercury is in infe- peak. The higher altitude brightening coincides with a in the wee hours. The Red rior conjunction, reduces atmospheric turbu- surge in Mars’ apparent size. Planet appears even more 2 p.m. EDT lence and improves seeing Its diameter swells from 5" on conspicuous thanks to its dis- 27 The Moon passes 4° conditions significantly, which February 10 to 10" on June 12, tinctive color and the lack of south of Neptune, more than offsets the planet’s any bright stars in Pisces and 2 a.m. EDT slightly smaller diameter. its neighbors. 29 The Moon passes Mars remains visible Mars remains a fixture in 3° south of Mars, noon EDT throughout 2020, though the evening sky through it’s strictly a morning the end of the year. And 31 The Moon passes 3° south of Uranus, object for the first six it shouldn’t be an after- 9 a.m. EDT months of the year. thought: Even on Uranus is at opposi- Be sure to watch it New Year’s Eve, it tion, noon EDT pass 0.7° south of gleams at magnitude –0.2 and Mars won’t appear this appears 10" across big or bright until 2035. from its perch 60° STEVE LEE (UNIVERSITY OF COLORADO)/JIM BELL (CORNELL high in the south as UNIVERSITY)/MIKE WOLFF (SSI)/NASA darkness falls.

www.Astronomy.com 11 2020 Nov Dark skies for S M T W T F S 1 2 3 4 5 6 7 9 10 11 12 13 14 autumn meteors 16 17 18 19 20 22 23 24 25 26 27 28 29 bservers can expect a flurry of meteors the morning of 10 Mercury is at November 17. greatest western That’s when the annual Leonid elongation (19°), O noon EST meteor shower reaches its peak. Viewers under a dark 12 The Moon passes 3° north of Venus, sky should then see up to 4 p.m. EST 20 “shooting stars” per hour. 13 The Moon passes This year’s shower occurs 1.7° north of only two days after New Moon, Mercury, 4 p.m. EST which leaves the prime viewing 15 Venus passes 4° hours after midnight free from north of Spica, our satellite’s interference. 8 a.m. EST Meteor rates spike in the pre- 17 Leonid meteor This Leonid meteor pierced the heart of Orion in 2018, passing through the shower peaks dawn hours because Earth then Hunter’s Belt just north of the Orion Nebula (M42). CRAIG BURTIS faces the direction of its orbital 19 The Moon passes 2° south of Jupiter, motion. (It’s the same reason Earth’s atmosphere, friction per hour. But both of these dis- 4 a.m. EST why a snowstorm looks much with air molecules incinerates plays are mere warmups for the The Moon passes worse out the front windshield them and produces the streaks year’s best shower: December’s 3° south of Saturn, of a moving car.) It also helps of light we see. Leonids blaze Geminids. Observers under a 10 a.m. EST that the shower’s radiant, into the atmosphere at 44 miles dark sky can expect to see up to 23 The Moon passes 5° which lies in the constellation per second, the fastest of any 150 meteors per hour — that’s south of Neptune, Leo the Lion, climbs highest shower meteors. The high better than two per minute, on 7 a.m. EST around the time morning twi- speeds mean they produce a average — when the shower 25 The Moon passes light begins. To see the most greater percentage of fireballs peaks at New Moon the night 5° south of Mars, meteors, observe from a site far than most showers. of December 13/14. 3 p.m. EST from the lights of civilization The Leonids are the middle Early January 2020’s 27 The Moon passes 3° south of Uranus, where you can take in a wide cog in a string of great meteor Quadrantid shower is nearly as noon EST swath of sky. showers lined up for 2020’s prolific, with a peak rate of 120 30 Penumbral lunar Leonid meteors stem closing months. The Orionids meteors per hour. The waxing eclipse, 4 a.m. EST from dusty debris ejected by in October likewise peak under gibbous Moon sets around Comet 55P/Tempel-Tuttle dur- a waxing crescent Moon that 1 a.m. local time, leaving nearly ing its countless trips through sets well before midnight. In five hours of unspoiled view- the inner solar system. When recent years, this shower has ing. Unfortunately, the third these dust particles slam into produced 20 to 25 meteors great annual meteor shower — the Perseids in August — Meteor showers in 2020 shares the sky with a fat crescent Moon. Although Luna’s Name Peak date Moon’s phase Prospects presence will drown out fainter Quadrantids Jan. 4 Waxing gibbous Good meteors, observers shouldn’t Lyrids April 22 New Moon Excellent skip this summer favorite. Eta Aquariids May 5 Waxing gibbous Poor Astronomers predict that Earth Perseids Aug. 12 Waning crescent Fair may encounter a denser fila- Orionids Oct. 21 Waxing crescent Excellent ment of comet debris around Leonids Nov. 17 Waxing crescent Excellent 6 a.m. EDT on August 12, Geminids Dec. 13 New Moon Excellent timed perfectly for viewers in western North America.

12 Sky Guide 2020 2020 Totality returns to Dec S M T W T F S 1 2 3 4 5 South America 6 8 9 10 11 12 13 15 16 17 18 19 20 22 23 24 25 26 27 28 30 31 n December 14, for the second South America time in a year Santiago and a half, a Buenos Aires total solar 12 The Moon passes REI 0.8° north of Venus, eclipse graces the skies above O 4 p.m. EST Chile and Argentina. This year, CILE Geminid meteor Temuco Neuquén Bahía Blanca 13 however, the path of totality shower peaks Pa lies some 600 miles farther Valdivia th of Atlantic totalit 14 Total solar eclipse, south. The eclipse occurs near Puerto Ocean Montt 11 a.m. EST noon just one week before the Paci c Ocean 16 The Moon passes summer solstice, so the Sun 3° south of Jupiter, will appear much higher in the 0 100 200 miles 11 p.m. EST

sky than it did during the July 0 150 300 km The Moon passes 2019 spectacle. Summertime 3° south of Saturn, weather means good viewing The December 14 total solar eclipse promises superb views for observers midnight EST positioned along a narrow path that crosses Chile and Argentina. prospects across most of the ASY-SG0120_30 19 Mercury is in supe- eclipse path, with slightly rior conjunction, 10 p.m. EST cloudier conditions in Chile. Totality begins at sunrise 20 The Moon passes 5° south of Neptune, over the South Pacific, but the 3 p.m. EST real thrills don’t start until the 21 Solstice (northern Moon’s umbral shadow hits winter/southern the Chilean coast southwest summer begins), of Temuco. Totality there lasts 5 a.m. EST 2 minutes 9 seconds beginning Jupiter passes 0.1° at 1:00 p.m. Chile Summer south of Saturn, 9 a.m. EST Time. The shadow moves quickly inland, cutting across 22 Venus passes 6° north of Antares, Villarrica National Park, which 8 p.m. EST lays claim to three volcanoes. 23 The Moon passes The eclipse path then 6° south of Mars, enters Argentina in the pic- 2 p.m. EST turesque Patagonia region, The Moon passes This month’s solar eclipse occurs near solar minimum, so the Sun should 24 which should prove to be a big 3° south of Uranus, display long coronal streamers like it did in August 2017. JOHN FISANOTTI attraction for eclipse chasers. 6 p.m. EST Greatest duration — 2 minutes of excitement both before and to cover the entire solar disk, 10 seconds starting at 1:12 p.m. after totality. During these cuts a narrow track across Argentina Time — occurs in stages where the Moon does Africa and southern Asia the central part of the country not completely cover the Sun, on June 21. At maximum in not far north of the tiny town observers need to use safe northern India, the Moon of Sierra Colorada. By the solar-viewing techniques to blocks 99 percent of the Sun’s time the umbral shadow leaves avoid serious eye damage. area. Four lunar eclipses take Argentina near La Loberia, The December 14 event is place in 2020. In each case, the duration along the cen- the highlight of 2020 eclipse however, Luna only enters ter line drops only slightly, viewing. An annular eclipse, Earth’s lighter penumbral to 2 minutes 9 seconds. The where the Moon passes shadow, so observers won’t eclipse’s partial phases, of directly in front of the Sun but see the Full Moon darken course, add more than an hour does not appear big enough significantly.

www.Astronomy.com 13 Left: A partial lunar eclipse visits North America on November 18/19, mimicking this view from August 16, 2008. ANTHONY AYIOMAMITIS

Below: Observers across much of southern Ontario will witness an annular solar eclipse as the Sun 2021 rises June 10. Preview DARREN TRIZZINO Looking ahead to next year . . .

ECLIPSE VIEWERS’ FOCUS The solar system’s planets should prove shifts from the Sun to the Moon in 2021. equally fascinating. Mars continues its fine After 2020 brought us only penumbral lunar appearance into early 2021. On January 1, it eclipses, 2021 welcomes one total and one stands high in the evening sky while shining deep partial event. The May 26 eclipse deliv- at magnitude –0.2 and spanning 10" when ers 18 minutes of totality for observers across viewed through a telescope. The Red Planet the western half of North America. (The remains brighter than magnitude 1.0 into continent’s eastern half experiences only the early March. Meanwhile, Venus puts on a preliminary partial phases.) And on the great show as darkness falls in autumn. At night of November 18/19, every North greatest elongation October 29, the magni- American with a clear sky can watch Earth’s tude –4.5 inner planet lies nearly 15° high dark umbral shadow cover 98 percent of the in the southwest 45 minutes after sunset. Full Moon. Jupiter and Saturn remain companions Although solar eclipses take a back seat throughout 2021. They reach opposition in 2021, two intriguing events should entice within three weeks of each other in August. astronomy enthusiasts. On June 10, the Moon Jupiter peaks at magnitude –2.9 while sport- crosses in front of the Sun but doesn’t block it ing a 49"-diameter disk. Saturn reaches entirely, bringing an annular eclipse to parts magnitude 0.2 and displays a ring system of Canada, Greenland, and Siberia. The that spans 42". eclipse begins at sunrise in southern Ontario, Fortunes reverse for the three main meteor where viewers can see 3 minutes 37 seconds showers in 2021. The Quadrantids and of annularity. Residents across much of the Geminids both battle a bright Moon, though northern and eastern U.S. can witness a par- the latter shower enjoys a few dark hours tial eclipse at daybreak. The December 4 total before dawn. The Perseids rebound nicely A Perseid meteor streaked beside the Milky eclipse presents more of a challenge because in 2021, however, peaking under a waxing Way during the 2018 shower. Similarly great it makes landfall only in Antarctica. crescent Moon that shouldn’t interfere at all. scenes await viewers this year. JOSHUA RHOADES

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