Sky Guide 2013 - Astronomy/media/Files/PDF/Sky Guide 2013.pdfmore meteors per hour under good...

contents2 Jan. 2013 Meteors battle the Moon in 2013

3 Feb. 2013 Spend evenings with Mercury

4 March 2013 A bright comet in evening twilight

5 April 2013 Running rings around Saturn

6 May 2013 When the Sun and Moon align

7 June 2013 An active Sun means observing fun

8 July 2013 Under a changing light

9 Aug. 2013 Perseids receive a Hero’s welcome

10 Sept. 2013 A bright year for asteroids

11 Oct. 2013 Icy giants for chilly autumn nights

12 Nov. 2013 On safari for totality

13 Dec. 2013 Venus’ brilliant evening return

14 Jan. 2014 Jupiter gleams high in the sky

15 2014 Preview Looking ahead to next year

16 Spacecraft A year of exploration

Martin Ratcliffe provides professional planetarium development for Sky-Skan, Inc., from his home in Wichita, Kansas. Richard Talcott is a senior editor of Astronomy.

A supplement to Astronomy magazine

Sky Guide2013

by Martin Ratcliffe and Richard Talcott

618276

Saturn puts on a great show when it reaches opposition in late April. Observers on Earth can see many of the planet’s features, although not to the extent seen here by the Cassini spacecraft. NASA/JPL/SSI

© 2012 Kalmbach Publishing Co. This material may not be reproduced in any form without permission from the publisher. www.Astronomy.com

ASY-PB0113_20ASY-SM0112_12

10°

January 3, 4 A.M.Looking east-northeast

DR AC O

URSA MINOR URSA MAJOR

BO ÖTES

C ORONA BOREALIS

HERCULES

Radiant

Vega

Arcturus

Moon Phases

3 Quadrantid meteor shower peaks

5 The Moon passes 0.6° south of Spica, 3 p.m. EST

6 The Moon passes 4° south of Saturn, 8 p.m. EST

10 The Moon passes 3° north of Venus, 7 a.m. EST

13 The Moon passes 6° north of Mars, 7 a.m. EST

14 The Moon passes 6° north of Nep-tune, noon EST

16 The Moon passes 5° north of Uranus, midnight EST

18 Mercury is in supe-rior conjunction, 4 a.m. EST

21 The Moon passes 0.5° south of Jupi-ter, 10 p.m. EST

S M T W T F S1 2 3 5

6 7 8 9 10 1213 14 15 16 17 1920 21 22 23 24 2527 28 29 30 31 Every new year begins

with a bang — at least if you’re a dedicated meteor observer. One of the

most prolific annual showers ramps up to a sharp peak dur-ing the year’s initial week, bringing dozens if not 100 or more meteors per hour under good conditions. The 2013 Quadrantid meteor shower reaches its maximum the morning of January 3.

Unfortunately, a waning gibbous Moon shares the pre-dawn sky with this display of “shooting stars.” Our satellite’s bright light will wash out fainter meteors and render the brighter ones less dramatic. Not all is lost, however. The Quadrantids typically produce anywhere from 60 to 200 meteors per hour. Even if the Moon cuts the number in half, a reasonable estimate because the shower generates a high percentage of bright streaks, this shower should still rank among 2013’s best.

You can improve your meteor viewing with a couple of simple tricks. First, observe from a dark site — you don’t want city sky glow or a neigh-bor’s bright security light to add to the Moon’s glare. Next,

try to position yourself where a tree or building blocks the Moon and reduces its glare.

Quadrantid meteors form when small dust particles strike Earth’s atmosphere and vapor-ize from the heat of friction. These meteors travel at 25 miles per second (41 kilome-ters per second) and appear to radiate from a point in north-ern Boötes. The shower gets its name from the now-defunct constellation Quadrans Mura-lis, which occupied this area of sky when observers first described the shower during the 19th century.

Many of 2013’s other major meteor showers also fight bright moonlight. A waxing gibbous Moon remains in the sky almost until twilight begins at the April 22 peak of the Lyrid shower. The Orio-nids in October and the Leo-nids in November fare even worse, with a nearly Full Moon in the sky all night for both showers. And the Geminids, which peak December 14, have a single hour of darkness between moonset and the beginning of twilight. On a happier note, the waning cres-cent Moon won’t interfere with the Eta Aquarid peak the night of May 5/6.

But the year’s best meteor display promises to come during the Perseid shower. A waxing crescent Moon sets by 11 p.m. local daylight time August 11, leaving the prime viewing hours after midnight free from its illumination. See page 9 for more on this great summer shower.

2 Sky Guide 2013

Events that can be viewed with the naked eye

Events that can be viewed with binoculars

Events that can be viewed with a telescope

Meteors battle the Moon in 2013

First Quarter

Full Moon

Last Quarter

New Moon

Jan2013

Meteor showers in 2013

Name Peak date Moon’s phase ProspectsQuadrantids Jan. 3 Waning gibbous Fair Lyrids April 22 Waxing gibbous FairEta Aquarids May 5 Waning crescent GoodPerseids Aug. 12 Waxing crescent ExcellentOrionids Oct. 21 Waning gibbous PoorLeonids Nov. 17 Full Moon PoorGeminids Dec. 14 Waxing gibbous Fair

Meteors will streak across the early morning sky January 3 as the Quadrantid shower reaches its annual peak. Astronomy: Roen Kelly

5°

PEGASUS

AQUARIUS

February 11, 30 minutes after sunsetLooking west

Moon

Mercury

Mars

Enif

ASY-PB0113_21

1 The Moon passes 0.3° south of Spica, 9 p.m. EST

3 The Moon passes 3° south of Saturn, 5 a.m. EST

8 Mercury passes 0.3° north of Mars, 4 p.m. EST

11 The Moon passes 5° north of Mer-cury, 1 p.m. EST

13 The Moon passes 4° north of Uranus, 11 a.m. EST

16 Mercury is at greatest eastern elongation (18°), 4 p.m. EST

18 The Moon passes 0.9° south of Jupi-ter, 7 a.m. EST

21 Neptune is in conjunction with the Sun, 2 a.m. EST

S M T W T F S1 2

4 5 6 7 8 911 12 13 14 15 1618 19 20 21 22 23

24 26 27 28ou can catch

your first glimpse of Mercury this year shortly after the Sun sets in February. The

innermost planet pulls away from our star during the month’s first week. On the 1st, Mercury shines brightly (magnitude –1.1) and sets nearly an hour after the Sun.

If you watch during twi-light the next two weeks, you’ll see the planet climb progressively higher. On Feb-ruary 8, Mercury passes just 0.3° north of Mars. The inner planet then shines at magni-tude –1.0 — eight times brighter than its ruddy com-panion. You’ll likely need binoculars to catch Mars’ dim glow against the bright twilight. Three nights later, a slender crescent Moon appears some 5° to Mercury’s upper right.

The planet reaches the peak of this evening appari-tion at greatest elongation February 16. It then lies 18° east of the Sun and stands 11° above the western horizon 30 minutes after sunset for observers at mid-northern latitudes. Afterward, Mercury sinks into the solar glare as quickly as it rose, disappearing from view by month’s close.

Getting a clear look at the innermost planet depends on several factors. Because it never strays far from the Sun, Mercury appears only low in the west after sunset or in the east before sunrise. It climbs highest around the times of greatest elongation, but not all such configurations are cre-ated equal. Your local setting

also plays a role — build-ings, trees, or hills can obstruct your view.

Mercury makes five other appearances during 2013. It puts on a similarly good evening show in late May and early June, although the company it keeps then far outshines the glow Mars offers in February. From May 24 to 28, Mercury, Venus, and Jupiter lie within 4° of one another. (Venus is the bright-est of this trio and Mercury the faintest.) After Mercury reaches greatest elongation June 12, it heads back toward the Sun and passes just 2° from Venus on the 20th.

The innermost planet’s best morning appearance of 2013 for Northern Hemisphere observers occurs around the time of its November 17 great-est western elongation. It then lies 12° high in the east-southeast 30 minutes before sunrise. It appears nearly as high before dawn in late July.

For viewers who live at mid-northern latitudes,

Mercury’s worst appearances come around greatest elonga-tion March 31 (morning sky) and October 9 (evening sky). Solar system geometry then favors viewers south of the equator. For observers at 30° south latitude in late March, the planet appears some 20° above the eastern horizon 30 minutes before sunrise. At October’s greatest elonga-tion, Mercury climbs equally high in the west a half-hour after sunset.

www.Astronomy.com 3

Spend evenings with Mercury

Feb2013

YMercury’s pockmarked surface displays circular craters, deep basins, bright rays, and maybe water ice to the sharp eyes of NASA’s MESSENGER spacecraft. NASA/JHUAPL/CIW

Mercury puts on a nice show in February’s evening sky. On the 11th, the innermost planet lies between the Moon and Mars.

Astr

onom

y: R

oen

Kelly

5°

ASY-PB0113_22

PEGASUS

ANDROMEDA

ARIES

PISCES

M31

α

γ

β

α

β

αγ

β

Path of Comet C/2011 L4

15

20

25

30

April 4

9 N

E E

March 10

1 The Moon passes 0.1° south of Spica, 2 a.m. EST

2 The Moon passes 3° south of Saturn, 10 a.m. EST

4 Mercury is in inferior conjunc-tion, 8 a.m. EST

10 The Moon passes 6° north of Nep-tune, noon EDT

17 The Moon passes 1.5° south of Jupiter, 9 p.m. EDT

20 Equinox (northern spring/southern autumn begins), 7 a.m. EDT

24 Jupiter passes 5° north of Aldebaran, 2 p.m. EDT

28 The Moon passes 0.005° north of Spica, 11 a.m. EDT

Venus is in superior conjunc-tion, 1 p.m. EDT

Uranus is in con-junction with the Sun, 9 p.m. EDT

29 The Moon passes 3° south of Saturn, 4 p.m. EDT

31 Mercury is at greatest western elongation (28°), 6 p.m. EDT

S M T W T F S1 2

3 5 6 7 8 910 12 13 14 15 1617 18 20 21 22 2324 25 26 28 29 30

31

4 Sky Guide 2013

dazzling comet can ignite a viewer’s passion better than almost any other celestial

object. Those flames could burn bright this month for seasoned observers and nov-ices alike — astronomers forecast Comet C/2011 L4 (PanSTARRS) will glow brighter than any comet in the past six years. And for those in the Northern Hemisphere, this could be the brightest easy-to-view comet since the 1990s.

Researchers discovered this comet June 6, 2011, on images taken through the 1.8-meter Panoramic Survey Telescope and Rapid Response System (PanSTARRS) on Haleakala in Hawaii. At the time, the object glowed dimly at 19th magnitude. But its time as an inconspicuous visitor from the distant Oort Cloud will soon be over.

If predictions hold true — never a sure thing when it comes to comets making their first trip through the inner solar system — C/2011 L4 will become a superb object when viewed through binoculars and probably an impressive naked-eye sight. It could peak as bright as magnitude 0 during the first half of March.

Southern Hemisphere observers will have the best views during January and Feb-ruary. In 2013’s first month, the comet should reach 7th magnitude as it crosses Scor-pius and Corona Australis and appears low in the east before dawn. It brightens consider-ably — perhaps to 2nd mag-nitude — and tracks more

rapidly eastward during Febru-ary. Early morning observers south of the equator will find it passing through southern Sagittarius, Corona Australis, Microscopium, Grus, and Piscis Austrinus.

The comet pushes north-ward during March, when it becomes visible in the evening sky for Northern Hemisphere observers. The earliest views should come around March 6 or 7, when it appears a degree above the western horizon 30 minutes after sunset. Each fol-lowing day, the comet climbs 1° to 2° higher, which dramati-cally improves its visibility. By the time it reaches perihelion (its closest approach to the Sun) March 9/10, C/2011 L4 lies 7° high in the west 30 min-utes after sunset and should shine at magnitude 0. As dusk soaks up the Sun’s rays and the sky darkens, the comet’s ethe-real tail should come into view.

From perihelion to the end of March, the comet moves almost due north through Pisces and Andromeda while its brightness drops by about a magnitude every five days. The tail of PanSTARRS swings through 90°, turning from east

to north. Depending on how much dust the comet pro-duces, this could create a nice broad dust tail to go along with a finer, straighter gas tail.

The comet should fade to 4th magnitude by early April, which would make the extended object visible only through binoculars or a tele-scope. It passes 2.5° west of the Andromeda Galaxy (M31) on the 3rd, then crosses into Cas-siopeia on the 9th.

As good as C/2011 L4 could be, it might be only the second-best comet of 2013. As this issue was going to press, astron-omers were predicting that C/2012 S1 (ISON) could peak as bright as magnitude –12 in late November. To learn more about this potentially great comet, see the article in the January 2013 Astronomy.

March2013

A bright comet in evening twilight

A

Comet C/2011 L4 (PanSTARRS) glowed at 19th magnitude when astronomers discovered it in June 2011. It should be a fine sight in the evening sky during March.

This spring’s best comet cuts through Pisces and Andromeda during March as it comes into view after sunset. Astronomy: Roen Kelly

Hen

ry H

sieh

/PS1

SC

1°

Saturn reaches opposition April 28

ASY-PB0113_23

N

E

VIRGO

LIBR A

α

κ

λ

μ

March 1April 1

May 1

June 1 July 1

6 The Moon passes 6° north of Nep-tune, 9 p.m. EDT

8 The Moon passes 7° north of Mer-cury, 6 a.m. EDT

14 The Moon passes 2° south of Jupiter, 2 p.m. EDT

17 Mars is in conjunc-tion with the Sun, 8 p.m. EDT

19 Mercury passes 2° south of Uranus, 5 p.m. EDT

22 Lyrid meteor shower peaks

24 The Moon passes 0.004° north of Spica, 8 p.m. EDT

25 Partial lunar eclipse, 4 p.m. EDT

The Moon passes 4° south of Saturn, 10 p.m. EDT

28 Saturn is at opposi-tion, 4 a.m. EDT

S M T W T F S1 2 4 5 6

7 8 9 11 12 1314 15 16 17 19 2021 22 23 24 26 2728 29 30

April

Saturn appears magnificent from January through September, but it reaches its peak

when it lies opposite the Sun in our sky in late April. At opposition, any outer planet rises near sunset and remains visible all night. But more importantly, the planet then lies closest to Earth, so it shines brighter and appears larger when viewed through a telescope than at any other time of the year.

Saturn begins the year among the relatively faint background stars of Libra. This region rises around 2:30 a.m. local time and lies high in the southeast as twi-light begins. But Saturn pokes above the horizon a few min-utes earlier every day. By mid-February, you can find it low in the eastern sky at midnight.

Saturn continues to rise earlier and grow more promi-nent as it approaches its April 28 opposition. The planet then shines at magnitude 0.1 and easily surpasses its stellar neighbors. When viewed through a telescope, Saturn’s disk spans 19" across its equa-tor and 17" through the poles — a difference that’s easy to see through any size instrument.

This assumes, of course, that you aren’t totally enthralled with the planet’s gorgeous ring system. At opposition, the rings span 43" and tilt 18° to our line of sight. They haven’t appeared this open since 2006, which makes this a great year to explore their structure. You easily will see the 2,900-mile-wide Cas-sini Division that separates the outer A ring from the brighter B ring. On nights with steady viewing conditions, you

should be able to spot the semitransparent C ring that lies closest to Saturn as well.

After opposition, the ringed planet remains promi-nent throughout the spring and summer. Unlike other bright planets, Saturn doesn’t change its appearance much as it moves away from peak visibility. Its brightness varies by just 0.6 magnitude during 2013, and the rings look beau-tiful at almost any scale.

Saturn’s westward motion relative to the background stars carries it into Virgo in mid-May. The planet spends most of June and July in the company of 4th-magnitude Kappa (κ) Virginis before it loops back eastward. It returns to Libra in early September.

As Saturn dips toward the western horizon in September, it passes 4° from brilliant Venus on the 19th. Three weeks later (October 10), the ringed planet appears 5° from Mercury, although the pair will be low enough in evening twilight to prevent good views. These two have a better conjunction after they move into the morning sky. On November 26, Mercury passes just 0.3° from Saturn in the predawn twilight. Saturn closes out the year shining conspicuously in the southeast before dawn.

2013

www.Astronomy.com 5

Running ringsaround Saturn

The ringed planet resides in western Libra at its peak this year, not far from the constellation’s border with Virgo. Saturn shines noticeably brighter than the nearby background stars. Astronomy: Roen Kelly

Saturn’s rings open wider this year. At opposition in late April, the rings tilt 18° to our line of sight and appear stunning even through small telescopes.

NA

SA/E

SA/H

ubbl

e H

erita

ge T

eam

(STS

cI/A

URA

)

A U S T R A L I A

NORTHERN TERRITORY QUEENSLAND

Melbourne

Eclipse beginsat sunrise

Darwin

Brisbane

Cairns

Sydney

500 miles

1000 km

0

ASY-PB0113_24

Path of annularity

WESTERN AUSTRALIA

PAPUA NEW GUINEA

SOLOMON ISLANDS

Perth

4 The Moon passes 6° north of Nep-tune, 3 a.m. EDT

5 Eta Aquarid meteor shower peaks

6 The Moon passes 4° north of Uranus, 8 p.m. EDT

9 Annular solar eclipse, 8 p.m. EDT

10 Asteroid Pallas is in conjunction with the Sun, 5 p.m. EDT

11 Mercury is in superior conjunc-tion, 5 p.m. EDT

12 The Moon passes 3° south of Jupiter, 9 a.m. EDT

18 Venus passes 6° north of Aldebaran, 6 a.m. EDT

20 Mercury passes 7° north of Aldebaran, 9 p.m. EDT


23 The Moon passes 4° south of Saturn, 6 a.m. EDT

24 Mercury passes 1.4° north of Venus, midnight EDT

Penumbral lunar eclipse, midnight EDT

27 Mercury passes 2° north of Jupiter, 6 a.m. EDT

28 Venus passes 1.0° north of Jupiter, 5 p.m. EDT


S M T W T F S1 3 4

5 6 7 8 10 1112 13 14 15 16 1719 20 21 22 23 2426 27 28 29 30

6 Sky Guide 2013

Some of the most beautiful sky events involve shadow play — either when the Moon casts its

shadow onto Earth or our planet blocks sunlight from reaching the Moon. Five such eclipses occur in 2013, although the solar variety (when our satellite lies between the Sun and Earth) perform significantly better than the lunar type (when our world plays the central role).

On May 9/10, an impressive solar eclipse will cover a simi-lar stretch of land as last November’s eclipse. This time, however, the Moon lies farther from Earth than average, so it doesn’t completely cover the Sun. This leaves a ring of sun-light visible to people situated along the central track, creat-ing an annular eclipse as opposed to the total one six months earlier.

The path of annularity begins at sunrise May 10 in Western Australia, crosses the Northern Territory, and then

cuts across Queensland north-west of Cairns. People on the center line in Queensland will witness more than four min-utes of annularity. Although November’s eclipse immersed Cairns in totality, some of the same regions northwest of there lie within both tracks.

After the Moon’s shadow leaves Australia, it crosses the southeastern tip of Papua New Guinea and some of the Solo-mon Islands before heading across the Pacific. Although the annular eclipse makes no other significant landfall, many islands experience a partial eclipse. People on the southern coast of Hawaii’s Big Island will see the Moon cover 50 percent of the Sun at 3:52 p.m. HST May 9. Those in Hono-lulu will witness 44 percent of the Sun disappear at 3:48 p.m. HST. Because the Moon never completely covers the Sun dur-ing this eclipse, viewers will need to use safe solar filters.

Nearly six months later, 2013’s second solar eclipse promises to be even more

spectacular. On November 3, the Moon fully blocks the Sun for people along a narrow path that cuts across central Africa. For details on this total eclipse, see page 12.

This year’s three eclipses of the Moon pale in comparison to its solar eclipses. On April 25, residents of Europe, Asia, Africa, and Australia can see a slim partial lunar eclipse. The Full Moon’s northern limb dips into Earth’s dark umbral shadow for 27 minutes. At maximum (20h07m UT), just 1.5 percent of the Moon’s diameter lies in the shadow.

And this stands as the year’s best lunar eclipse. On May 24/25 and October 18/19, the Moon slides through Earth’s lighter penumbral shadow. The first of these will be essen-tially undetectable, with only 2 percent of our satellite entering the shadow’s fringe.

North American observers might glimpse the second pen-umbral eclipse the evening of October 18. The Moon slides into the shadow starting at 5:51 p.m. EDT. By 7:50 p.m., about three-quarters of our satellite lies in the shadow. Sharp-eyed observers should see the Moon’s southern limb darken slightly around the peak.

May When the Sun and Moon align

2013

Australia is the place to be as the Sun rises May 10. Viewers with clear skies will witness an impressive annular eclipse. Astronomy: Roen Kelly

The Sun will look like a ring of fire at the peak of this month’s eclipse. The ring will appear slightly thinner than during this May 2012 eclipse. Ruben Kier

3 The Moon passes 4° north of Uranus, 4 a.m. EDT

10 The Moon passes 5° south of Venus, 7 a.m. EDT

The Moon passes 6° south of Mer-cury, 7 p.m. EDT

12 Mercury is at greatest eastern elongation (24°), 1 p.m. EDT

18 The Moon passes 0.1° north of Spica, 4 p.m. EDT

19 Jupiter is in con-junction with the Sun, noon EDT

The Moon passes 4° south of Saturn, 1 p.m. EDT

20 Mercury passes 1.9° south of Venus, 2 p.m. EDT

21 Solstice (northern summer/southern winter begins), 1 a.m. EDT

22 Venus passes 5° south of Pollux, 9 p.m. EDT



S M T W T F S1

2 3 4 5 6 79 10 11 12 13 14 15

17 18 19 20 21 2224 25 26 27 28 29If predictions hold true,

our star will reach its highest level of activity in a decade sometime this spring or summer.

Observers saw little activity from 2008 into 2010, and sev-eral months went by with no sunspots. But sunspot num-bers on our local star have been rising these past couple of years and seem poised to peak in 2013. (Solar scientists won’t know when maximum occurs until after the number of sunspots starts to fall.)

Observing the Sun can be exciting, but you have to be cautious. Sunlight can quickly and painlessly injure your reti-nas, possibly leading to blind-ness, particularly if you view through a telescope. (The intense light can damage optics, too.) If you want a direct view of the Sun, you must use a safe solar filter that fits over your scope’s front end. The most common are white-light and specialized Hydrogen-alpha filters.

Alternatively, you can project the Sun’s image. Draw-ing a circle a few inches in diameter on a card lets you plot the positions of sunspots and forms a nice record of your observations. Use a tele-scope no larger than 4 inches in aperture to reduce heat buildup and a basic eyepiece that has few optical elements — the adhesives in some modern eyepieces can melt with prolonged solar viewing.

If you record sunspot posi-tions every day, you’ll soon discover that the Sun rotates. Observe long enough and you’ll discern our star’s period of rotation. Although the

equatorial regions take about 25 days to spin once around the Sun’s axis, you’ll record a period about two days longer because Earth’s orbital motion changes our perspective. Our star’s gaseous nature causes higher latitude regions to rotate more slowly.

During the approximately 11-year solar cycle, sunspots migrate from relatively high to lower latitudes. With their numbers now peaking, don’t be surprised to see two nearly parallel belts of these dark

blemishes standing astride the solar equator. Sunspots appear dark because they are some 2000° Fahrenheit cooler than the rest of the Sun’s surface.

Other signs of solar activity to look for include white-light flares and, if you view through a Hydrogen-alpha filter, bright prominences along the solar limb and dark filaments pro-jected against the solar disk. Although scientists predict the number of spots in this cycle will be significantly lower than normal, don’t let that discour-age you — astronomer Rich-ard Carrington observed the largest white-light flare ever recorded in 1859 during a similar level of solar activity.

Solar activity also can have effects closer to home. Strong flares and coronal mass ejec-tions can expel enough high-energy particles to damage orbiting spacecraft and power-line transmissions. And for observers, these particles pump energy into Earth’s magnetosphere, creating stun-ning auroral displays. So, even if you prefer your observing at night, this year’s solar maxi-mum holds great promise.

2013

www.Astronomy.com 7

An active Sun means observing fun

June

The Sun will display many sunspots and other activity as our star reaches the peak of its 11-year cycle. Jim Lafferty

Northern skywatchers should look for aurorae this year as the Sun bombards Earth’s magnetosphere with charged particles. Marvin Nauman

ASY-PB0113_26

L ACERTA

CEPHEUS

β

η

δ

N

E

3626

45 ν

42

α

36

46

2°

ζε

5°

ASY-PB0113_25

CETUSδ

Mira

N

E

νξ

μλ

αγ

ζ

τ

β

ιη

θ

1 Pluto is at opposi-tion, 8 p.m. EDT

6 The Moon passes 4° south of Mars, 8 a.m. EDT

9 Mercury is in infe-rior conjunction, 3 p.m. EDT

10 The Moon passes 7° south of Venus, 7 p.m. EDT

15 The Moon passes 0.3° north of Spica, midnight EDT


22 Venus passes 1.2° north of Regulus, 1 a.m. EDT

Mars passes 0.8° north of Jupiter, 2 a.m. EDT



30 Mercury is at great-est western elon-gation (20°), 5 a.m. EDT

S M T W T F S1 2 3 4 5 6

7 9 10 11 12 1314 16 17 18 19 2021 23 24 25 26 2728 30 31

8 Sky Guide 2013

stronomy offers sev-eral enticing deep-sky pursuits. Some observers prefer viewing splashy

star clusters, many appreciate glowing nebulae, and still oth-ers hunt down faraway galax-ies. Although they usually don’t get the attention heaped on their flashier cousins, variable stars also excite lots of skygaz-ers. It’s easy to identify many of these stars and estimate their brightnesses, and in some cases it takes only a minute or two.

The summer sky has a few bright ones to get you started. Two famous long-period vari-able stars — Mira (Omicron [ο] Ceti) and Chi (χ) Cygni — reach their peak this season. And Delta (δ) Cephei, a star important for its historic role in measuring cosmic distances, is on view every clear evening.

Let’s begin with Mira, which should reach maximum light in late July. It then lies one-third of the way to the zenith in the southeastern sky in the hour before dawn. Mira

typically ranges from 3rd to 10th magnitude over a 332-day period, though it occasionally grows even brighter. As it nears maximum this summer, it changes the appearance of Cetus the Whale. You can find the variable approximately 10° southwest of a conspicuous circle of stars that forms the Whale’s head.

Summer evenings feature two other bright variables. Chi Cygni, a pulsating variable similar to Mira, lies nearly overhead around midnight.

Its brightness ranges from 5th to 13th magnitude over a 407-day period. Near its maximum, Chi changes the appearance of Cygnus the Swan by adding a star to the bird’s neck. It should glow brightest in early June and remain visible to naked eyes in July and August.

Our final star, Delta Cephei, lies near the southeastern cor-ner of Cepheus the King. Delta sits at the eastern apex of a small triangle it forms with Zeta (ζ) and Epsilon (ε) Cep, a pair of stars separated by two Full Moon-widths.

Delta varies between mag-nitudes 3.5 and 4.4 over a 5.4-day period. This makes it ideal for a quick estimate every clear night, and you can witness its entire cycle within a week. Zeta and Epsilon Cep nearly span Delta’s brightness range, with Zeta shining at magni-tude 3.6 and its neighbor at magnitude 4.2. Variables like Delta pulsate with regular periods, and their luminosities correlate with their periods. This behavior makes such stars ideal for measuring distances throughout the local universe.

2013July Under a changing

light

A

Delta (δ) Cephei changes brightness by 0.9 magnitude every 5.4 days. (Numbers are magnitudes with decimal points left out.) Astronomy: Roen Kelly

Mira varies from 3rd to 10th magnitude during a 332-day period. It should reach its peak in late July. Astronomy: Roen Kelly

ASY-PB0113_27

August 12, 1 A.M.Looking northeast

10°

CASSIOPEIAANDROMEDA

ARIES

PERSEUS

AURIGAPleiades

Polaris

Capella

Radiant


Asteroid Juno is at opposition, 9 p.m. EDT


Mercury passes 7° south of Pollux, 11 p.m. EDT

5 The Moon passes 4° south of Mer-cury, 5 a.m. EDT

9 The Moon passes 5° south of Venus, 10 p.m. EDT


Perseid meteor shower peaks

13 The Moon passes 3° south of Saturn, 4 a.m. EDT

17 Asteroid Ceres is in conjunction with the Sun, 9 p.m. EDT

19 Mars passes 6° south of Pollux, 8 a.m. EDT



Mercury is in superior conjunc-tion, 5 p.m. EDT

26 Neptune is at opposition, 10 p.m. EDT


S M T W T F S1 2 3

4 5 7 8 9 1011 12 13 15 16 1718 19 21 22 23 2425 26 27 29 30 31

lthough this is a down year for meteor showers overall, the Per-seids are a nota-

ble exception. While the other major showers share the sky with the Moon, the Perseids peak under Moon-free condi-tions the morning of August 12. From mid-northern lati-tudes, the five-day-old cres-cent Moon sets shortly after 10 p.m. local daylight time on the 11th. As always, you’ll see more meteors at a viewing site far from artificial lights.

It actually takes a few weeks for our planet to cross the broad trail of debris ejected over millennia by Comet 109P/Swift-Tuttle. Each time the comet enters the inner solar system (a feat it performs every 133 years), the Sun’s heat evaporates some of the ices in the nucleus, which liberates plenty of dust. This debris eventually spreads along the comet’s entire orbit. Perseid meteors result when Earth plows through this debris and friction with the atmosphere vaporizes the dust particles.

Our planet encounters the leading edge of this trail in mid-July. The number of meteors gradually rises until the peak night, when rates top out at up to 100 meteors per hour. These high rates can last 10 hours, providing excellent views for observers across a wide range of longitudes. That helps North Americans this year because the peak should occur around noon August 12, leaving the pre-dawn hours of the 12th a little

better than the following morning. The number of meteors visible on succeeding nights falls until Earth exits the debris stream around August 24.

Throughout this period, the Milky Way arches nearly overhead during the predawn hours. This is a favorite back-drop for viewers to scan for meteors and photographers to capture the bright streaks. Many Perseids leave a persis-tent train — a glowing tunnel of ionized gas in the atmos-phere created by a particularly bright meteor.

The Perseids get their name from the constellation Perseus. All of the meteors appear to emanate from a region near the border between this constellation and its neighbor, Cassiopeia. This is purely a perspective effect — the meteors travel on paral-lel paths, but our location on Earth creates the illusion of diverging trails.

Although observers will see more meteors in the hours

before twilight begins, keep watching as the sky starts to brighten. By this time, the radiant lies nearly over-head and you’re on the part of the planet heading straight into the dusty debris stream. The meteors then hit the atmos phere at top speed — some 37 miles per second — and consequently appear especially bright.

2013

www.Astronomy.com 9

AugPerseids receive a Hero’s welcome

A

The Moon sets before the 2013 Perseid meteor shower peaks, allowing viewers under a clear, dark sky to see up to 100 meteors per hour.

Astr

onom

y: R

oen

Kelly

This bright Perseid meteor highlighted the 2012 shower. A waxing crescent Moon sets well before midnight at this year’s peak, leaving a dark predawn sky.

Tony

Row

ell

1°

7

ASY-PB0113_28

PISCES

PEGASUS

Bamberga reachesopposition September 13

Sept 1

6

11

1621

26

Oct 1

ρ

β

γ

N

E


5 Venus passes 1.8° north of Spica, 9 a.m. EDT


The Moon passes 0.4° south of Venus, 5 p.m. EDT



19 Venus passes 4° south of Saturn, 8 p.m. EDT


22 Equinox (northern autumn/southern spring begins), 5 p.m. EDT

24 Mercury passes 0.8° north of Spica, 3 p.m. EDT

28 The Moon passes 5° south of Jupiter, 5 a.m. EDT

S M T W T F S1 2 3 4 6 78 9 10 11 13 14

15 16 17 18 20 2122 23 24 25 27 2829 30

10 Sky Guide 2013

More than 100,000 aster-oids lurk between the orbits of Mars

and Jupiter. Because of Jupiter’s gravitational influence, these objects failed to coalesce into a full-fledged planet during the solar system’s earliest days. A few of the largest of these proto planets now orbit the Sun in the company of a vast num-ber of smaller bodies created by subsequent collisions.

Although this so-called asteroid belt holds many tempt-ing targets, backyard observers tend to concentrate on four — Ceres, Pallas, Juno, and Vesta — that were the first ones discovered. But 2013 holds a surprise: The two brightest asteroids to reach opposition and peak visibility rarely appear on viewers’ radar screens. Bam-berga is at its best September 13 while Iris appears finest August 16 and remains a nice sight well into September.

Johann Parisa first detected 324 Bamberga in February 1892, one of 122 asteroids the Austrian astronomer discov-ered. The space rock begins September glowing at magni-tude 8.3 inside the familiar Circlet asterism in western Pisces, just below the Great Square of Pegasus. By opposi-tion, Bamberga brightens to magnitude 8.1 and lies even closer to Pisces’ northwestern corner. The asteroid shines brightly enough to show up through binoculars, though a telescope makes it somewhat easier to track down.

Englishman John Russell Hind discovered 7 Iris in August 1847. At opposition this year, the asteroid glows at magnitude 7.9 and appears within 1° of the magnitude 2.9 star Beta (β) Aquarii. By Sep-tember, Iris has faded slightly and lies among the background stars of western Aquarius.

Although Bamberga and Iris are the brightest asteroids

that reach opposition in 2013, 1 Ceres and 4 Vesta are worth targeting early in the year. Both reached opposition in Decem-ber 2012 and remain 7th- magnitude objects in Taurus during January. To find them, see the map on page 43 of Astronomy’s January 2013 issue.

Ceres passes 2° south of magnitude 1.7 Beta Tauri early in the month. It then heads a few degrees west before looping back and coming even closer to the star in early March. Vesta lies in a more crowded region — near the striking V-shaped Hyades star cluster — some 10° to 15° southwest of Ceres. Dur-ing January’s final week, Vesta remains nearly stationary just 3° north of 1st-magnitude Aldebaran and 1° east of mag-nitude 3.5 Epsilon (ε) Tau, the star that marks the Hyades’ northeastern tip.

Ceres and Vesta continue to be newsmakers for more than their visibility. NASA’s Dawn spacecraft orbited Vesta from July 2011 to September 2012. The probe discovered a series of equatorial grooves, analyzed the asteroid’s diverse composi-tion, and mapped a giant cra-ter and mountain peak at the object’s south pole. Dawn is now making its way to Ceres, which it should reach in early 2015. Observations from Earth show Ceres to be icier than rocky Vesta. In a few years, planetary scientists should know for sure.

Sept2013A bright year for asteroids

NASA’s Dawn spacecraft captured this portrait of Vesta during its 14-month asteroid reconnaissance. The probe is now heading toward a rendezvous with Ceres in 2015.

Asteroid Bamberga reaches opposition and peak visibility in September, when it glows at 8th magnitude. The object then resides among the stars of western Pisces. Astronomy: Roen Kelly

NA

SA/J

PL-C

alte

ch/U

CLA

/MPS

/DLR

/IDA

2°

ASY-PB0113_29

CETUS

PISCES

Uranus

ζ

ω

δε

E

N

20


3 Uranus is at opposi-tion, 10 a.m. EDT

6 The Moon passes 3° north of Mer-cury, 6 p.m. EDT

The Moon passes 1.9° south of Sat-urn, midnight EDT

8 The Moon passes 5° north of Venus, 8 a.m. EDT

9 Mercury is at greatest eastern elongation (25°), 6 a.m. EDT

10 Mercury passes 5° south of Saturn, 3 p.m. EDT

14 Mars passes 1.0° north of Regulus, 6 p.m. EDT


16 Venus passes 1.6° north of Antares, noon EDT


18 Penumbral lunar eclipse, 8 p.m. EDT

21 Orionid meteor shower peaks


29 The Moon passes 6° south of Mars, 9 p.m. EDT

S M T W T F S1 2 3 5

6 7 8 9 10 1213 14 15 16 17 1920 21 22 23 24 2527 28 29 30 31The outermost

major planets come to opposition within several weeks of each

other in 2013. Uranus reaches its peak October 3, less than six weeks after its more distant sister planet, Neptune. Both will be easy to find and fasci-nating to observe these fall evenings. Simply seeing the light from these worlds at the solar system’s edge evokes mystery and wonder.

Although planetary scien-tists now use the term ice giant to describe these outer worlds, don’t think of them as massive balls of frozen ice. The description caught on as a way to differentiate Uranus and Neptune from their larger cousins, the gas giants Jupiter and Saturn. By “ice,” scientists mean Uranus and Neptune have relatively high abun-dances of substances such as water and methane while both Jupiter and Saturn consist

almost entirely of hydrogen and helium. The large number of exoplanets with masses similar to Uranus and Nep-tune discovered in the past several years shows the impor-tance of this class of planet.

Uranus is easier to locate. It spends 2013 wandering in a sparse region near the border between Pisces and Cetus. The planet shines at magnitude 5.7 at opposition, bright enough to show up to naked eyes from a dark site. It’s much easier to view through binoculars, however. Uranus lies in the same binocular field as the magnitude 4.4 star Delta (δ) Piscium. At opposition, the planet lies 5° south-southwest of the star. On October 14, Uranus moves within 7' of a magnitude 6.4 sun. Crank up the magnification, and you’ll see the planet’s 3.7"-diameter blue-green disk.

You’ll need a bit more per-severance to track down Nep-tune. Although this distant world reaches opposition August 26, it lies so far from Earth (some 2.7 billion miles) that its appearance hardly changes during the next sev-eral months. It remains at its peak magnitude of 7.8 until mid-October and doesn’t fade below magnitude 7.9 until 2014. It also stands higher in the evening sky during autumn than in late summer.

You’ll need binoculars or a telescope to spot Neptune. It resides among the background stars of Aquarius, roughly midway between Sigma (σ) Aquarii (magnitude 4.8) and 38 Aqr (magnitude 5.4) throughout the summer and fall. These two stars lie 5° apart and will appear in the same binocular field. Turn a telescope on Neptune and boost the magnification to see its tiny blue-gray disk, which measures just over 2" across.

www.Astronomy.com 11

Icy giants for chilly autumn nights

Oct2013

Uranus’ bluish color stands out through backyard telescopes as well as in this Hubble image. The white spot at top is an aurora in the ice giant’s atmosphere.

Uranus lies in southern Pisces, near the border with Cetus, when it reaches opposition October 3. The magnitude 5.7 planet appears in the same binocular field as 4th-magnitude Delta (δ) Piscium. Astronomy: Roen Kelly

NA

SA/E

SA/L

aure

nt L

amy

(Par

is O

bser

vato

ry)

A F R I C A

1000 miles

1000 km

0

SOMALIAUGANDA

KENYA

ETHIOPIA

Greatest eclipse

Eclipse endsat sunset

DEM. REP.OF CONGO

LIBERIA

GABONCONGO

Path of totality

ASY-PB0113_30

1 Venus is at greatest eastern elongation (47°), 4 a.m. EDT

Mercury is in infe-rior conjunction, 4 p.m. EDT


3 Total solar eclipse, 8 a.m. EST

6 Saturn is in con-junction with the Sun, 7 a.m. EST

The Moon passes 8° north of Venus, 8 p.m. EST

11 The Moon passes 6° north of Nep-tune, 6 a.m. EST

13 The Moon passes 3° north of Uranus, 10 p.m. EST

17 Leonid meteor shower peaks

Mercury is at greatest western elongation (19°), 10 p.m. EST

21 The Moon passes 5° south of Jupiter, midnight EST

25 Mercury passes 0.3° south of Saturn, 11 p.m. EST

27 The Moon passes 6° south of Mars, 11 a.m. EST

29 The Moon passes 0.9° north of Spica, noon EST

S M T W T F S1 2

4 5 6 7 8 911 12 13 14 15 1618 19 20 21 22 23

24 26 27 28 29 30

12 Sky Guide 2013

The year’s preemi-nent eclipse arrives November 3, when the Moon passes between the Sun

and Earth and casts its shadow on our planet. This solar eclipse is special because it belongs to the rarest class. Only about 5 percent of all eclipses are hybrids — annular along part of the central track and total along the rest.

The Sun and Moon appear nearly the same size in our sky, about 0.5° in diameter. But neither the Moon’s orbit around Earth nor ours around the Sun is perfectly circular, so their dimensions change slightly during the course of the month and year. When the three objects line up precisely and the Moon appears a hair smaller than the Sun, as it does May 9/10, we see an annular eclipse. If the Moon looks a bit bigger than our star, observers see a total eclipse.

On November 3, the Moon and Sun are exactly the same apparent size for a brief sec-ond. At the start of the central eclipse, the Sun looms a tiny fraction larger and observers on the center line see the ring of fire of an annular eclipse.

But during the next couple of hours, the Moon moves about 300 miles closer to Earth and the shadow falls on a point more directly beneath the Moon and — voilà — totality!

The central path begins in the Atlantic Ocean about 600 miles due east of Jacksonville, Florida. Although few, if any, people will travel there to wit-ness annularity (which lasts just four seconds on a path 2.5 miles wide), residents along North America’s East Coast can see a partial eclipse at sunrise. From Boston, for example, the Moon will cover slightly less than two-thirds of

the Sun as the pair rises around 6:20 a.m. EST. The eclipse ends about 50 minutes later. People farther south and west will see less of our star blocked. (Remember to use a safe solar filter to view any partial eclipse.)

Less than 300 miles east-southeast of where the annular phase starts, the eclipse turns total and remains that way along the rest of the path. Max-imum eclipse occurs in the Atlantic some 200 miles south-west of Liberia, where totality lasts 1 minute and 39 seconds.

The Moon’s shadow makes no landfall until it reaches the African coast in Gabon north of Port-Gentil. On the center line there, totality lasts 1 min-ute and 8 seconds. The Moon’s shadow continues east and slightly north, rushing across narrow sections of Gabon, Congo, the Democratic Republic of the Congo, north-ern Uganda and Kenya, and southern Ethiopia before end-ing at sunset in Somalia. The duration of totality falls as the eclipse sweeps across equato-rial Africa, dropping to less than 25 seconds by the time it reaches Uganda.

On safari for totalityNov2013

Africa will be the center of the astronomical world November 3 when the Moon totally blocks the Sun from view. Astronomy: Roen Kelly

The Sun’s pearly white corona streams away from the Moon’s pitch-black disk during a total solar eclipse. This year’s only such eclipse occurs November 3. Jeff Buell

5°

ASY-PB0113_31

December 6, 1 hour after sunsetLooking southwest

SAGIT TARIUS

AQUIL A

CAPRIC ORNUS

Altair

Moon

Venus

1 The Moon passes 1.3° south of Saturn, 5 a.m. EST

5 The Moon passes 8° north of Venus, 7 p.m. EST

6 Venus is at greatest brilliancy, 2 p.m. EST

8 The Moon passes 6° north of Nep-tune, noon EST


14 Geminid meteor shower peaks

19 The Moon passes 5° south of Jupiter, 2 a.m. EST

21 Solstice (northern winter/southern summer begins), noon EST

25 The Moon passes 5° south of Mars, 10 p.m. EST

26 The Moon passes 1.1° north of Spica, 10 p.m. EST

28 The Moon passes 0.9° south of Sat-urn, 8 p.m. EST

29 Mercury is in supe-rior conjunction, 1 a.m. EST

S M T W T F S1 3 4 5 6 78 10 11 12 13 14

15 16 18 19 20 2122 23 24 26 27 2829 30 31

lthough Venus reaches its greatest elongation from the Sun on November 1, it

appears significantly higher in the evening sky in early December. The extra altitude makes it even more conspicu-ous when it shines brightest (magnitude –4.9) December 6.

Venus’ upward trend arises through solar system geom-etry. The ecliptic — the Sun’s apparent path across the sky that the planets follow closely — makes a shallow angle to the western horizon during early autumn from mid-northern latitudes. So, Venus’ elongation from our star translates more into distance along the hori-zon and less into elevation. But during November and December, the ecliptic’s angle steepens sharply, more than offsetting the planet’s smaller solar elongation. On Novem-ber 1, Venus appears 11° high in the southwest an hour after sunset; by December’s first week, it stands 15° high.

Venus first emerges into the evening sky during May. Although the planet lies low

in bright twilight, make an effort to view it during the month’s final week. On the 28th, it passes 1° north of Jupiter. Venus then shines at magnitude –3.9, two full mag-nitudes brighter than Jupiter. As a bonus, Mercury lies 3° from the pair.

Venus has several close encounters with bright stars during the summer and fall. It cruises 1.2° north of Regulus in Leo on July 21, 1.8° north of Spica in Virgo on September 5, and 1.6° north of Antares in Scorpius on October 16.

By the time it reaches great-est elongation November 1, Venus lies against the backdrop of the Milky Way just 2° north of the galaxy’s center. The sec-ond planet from the Sun then shines at magnitude –4.5 and appears 47° east of our star. As Venus continues its trek across

Sagittarius, it slides 3° south of the Lagoon Nebula (M8) on November 5 and 6. The 6th likely offers the finest view because a slim crescent Moon stands nearby. Use binoculars to see the Moon 7° north of Venus, with the Lagoon and Trifid (M20) nebulae midway between. The group lies low in the southwest as darkness falls, so view from a dark site with an unobstructed horizon and hope for clear skies.

A telescope reveals dra-matic changes on Venus during the year’s final two months. On November 1, the inner planet displays a 25"-diameter disk that appears half-lit. At the time of greatest brilliancy December 6, Venus shows a disk 41" across and one-quarter lit. By New Year’s Eve, the planet has swelled to 60" in diameter while its phase has waned to a thin sliver just 4 percent lit. It then appears less than 10° above the horizon 30 minutes after sunset; it will succumb to the Sun’s glare by the end of January’s first week.


2013DecVenus’ brilliant

evening return

A

Venus appears highest and brightest for Northern Hemisphere observers on evenings in early December. Astronomy: Roen Kelly

Venus’ thick clouds stand out in this ultraviolet image from the European Space Agency’s Venus Express spacecraft. ESA/MPS/DLR-PF/IDA

1°

ASY-PB0113_32

GEMINI

δ

εω

Jupiter reachesopposition January 5

Nov 15

March 15Feb 15Jan 15

Dec 15

ζ

N

E

1 Pluto is in conjunction with the Sun, 2 p.m. EST

3 Quadrantid meteor shower peaks

4 The Moon passes 5° north of Nep-tune, 9 p.m. EST

5 Jupiter is at opposi-tion, 4 p.m. EST


11 Venus is in inferior conjunction, 7 a.m. EST

15 The Moon passes 5° south of Jupiter, 1 a.m. EST

23 The Moon passes 4° south of Mars, 1 a.m. EST

25 The Moon passes 0.6° south of Saturn, 9 a.m. EST

28 Mars passes 5° north of Spica, 3 p.m. EST

The Moon passes 2° south of Venus, 10 p.m. EST

31 Mercury is at greatest eastern elongation (18°), 5 a.m. EST

S M T W T F S2 3 4

5 6 8 9 10 1112 13 14 16 17 1819 20 21 22 23 2526 27 28 29 31

14 Sky Guide 2013

Jupiter dominates the night sky in early 2014. It reaches oppo-sition and peak visibil-ity January 5, when it

shines at magnitude –2.7 and appears 47" across through a telescope. Even better for Northern Hemisphere observ-ers, the giant planet resides among the stars of Gemini, so it passes nearly overhead around midnight local time. This is as high as it’s been for northern observers in 12 years.

Jupiter doesn’t reach oppo-sition in 2013. This omission does not happen often for the solar system’s largest planet. The period between opposi-tions runs 399 days, or about 13 months. A simple calcula-tion shows that if Jupiter lies opposite the Sun in our sky in December (as it did December 2, 2012), it rules out an opposi-tion the following year. The next year void of a Jupiter opposition is 2025.

Despite the lack of peak viewing conditions, Jupiter is a

stunning object for much of 2013. As Janu-ary begins, its vital stats — a magnitude of –2.7 and an equatorial diameter of 47" — match those in January 2014. The planet graces the con-stellation Taurus in early 2013, lying between the Hya-des and Pleiades star clusters. After nearly all-night visibility during the winter and evening views during spring, Jupiter sets soon after twilight in May. It has a fine conjunction with Venus May 28, when the two brightest planets appear 1° apart with Mercury 3° away.

Jupiter reappears in the morning sky during July. It meets Mars on July 22, when the two lie less than 1° apart against the backdrop of Gem-ini. The giant planet rises ear-lier each night through late summer and autumn, coming

up around midnight in early October as it ushers in a return to the late-evening sky.

The gas giant moves east-ward relative to the starry background until November 7, when it becomes stationary and then starts traveling west-ward. As it loops through cen-tral Gemini, Jupiter twice passes close to magnitude 3.5 Delta (δ) Geminorum. On October 3/4, the planet skims 7' north of the star; on Decem-ber 10/11, 15' separate the pair.

When viewed through a telescope, Jupiter offers a stun-ning array of atmospheric fea-tures and four bright moons. The best views come during moments of good seeing, when Earth’s image-distorting atmos phere steadies and the planet’s disk sharpens. These moments happen most often when Jupiter lies high in the sky, so observers throughout the Northern Hemisphere should have spectacular views in late 2013 and early 2014.

Jupiter gleams high in the sky

Jan2014

Jupiter’s brilliance dominates the sky nearly all night during December 2013 and January 2014. The giant planet then lies among the background stars of central Gemini. Astronomy: Roen Kelly

Bright zones, dark belts, and the Great Red Spot highlight Jupiter’s atmosphere. The Cassini probe took this image when it flew past the gas giant in 2000. NASA/JPL/SSI


No one has seen a total eclipse of the Moon since December 2011, but the long drought ends with a veritable flood in 2014. On the night of April 14/15, the Full Moon dips deeply into Earth’s shadow. People throughout North America will have ringside seats for the entire show. The eclipse’s partial phases begin at 1:58 a.m. EDT. For the next hour or so, the Moon darkens as totality approaches. This peak stage lasts from 3:06 a.m. to 4:25 a.m. Our satellite should appear orange-red during totality as sunlight filters through Earth’s atmosphere. The partial phases wrap up at 5:33 a.m.

As if one encounter with totality isn’t enough, the Moon returns to Earth’s shadow the morning of October 8. This event’s partial phases commence at 5:14 a.m. EDT with totality following at 6:24 a.m. After 60 minutes immersed completely in our planet’s shadow, the Moon re-emerges at 7:24 a.m. Residents of western North America will have the best view of this eclipse, although even those on the East Coast will see at least some of totality.

No total solar eclipses grace our skies in 2014, but a partial eclipse takes place across most of North America the afternoon of October 23. People in most of the United States will see the Moon block more than 40 percent of the Sun’s disk while those

in the country’s northern states and in Canada will see more than 60 percent coverage. Maximum eclipse occurs in northern Canada, where 81 percent of the Sun will be hidden from view.

Planet-watchers can look forward to a dramatic appearance of Mars in the spring. The Red Planet reaches opposition April 8, when it shines at magnitude –1.3 and spans 15" when viewed through a telescope. It hasn’t appeared this big and bright since 2007. Meanwhile, Saturn looks gorgeous for a few months on either side of its May 10 opposition, and Jupiter reigns supreme around its early January peak. Watch for brilliant Venus to put on an impressive show before dawn in late winter and spring.

After a down year in 2013, meteor observers have better pros-pects in 2014. Although August’s Perseids must battle a nearly Full Moon, January’s Quadrantids have no lunar competition. And no other major meteor shower faces worse than a half-lit Moon. All in all, 2014 is shaping up as a stellar year for backyard skygazers.

2014 preview

Looking ahead to next year...

Hin

rich

Ber

nard

Bas

eman

n

The first total lunar eclipse in nearly three years arrives April 14/15, 2014, when the Moon will glow with a ruddy hue. Randy Brewer

North Americans can witness a partial solar eclipse October 23, 2014.Mars comes to opposition in April 2014, when it puts on its best show in more than six years. ESA/MPS/OSIRIS Team

16 Sky Guide 2013

Since its launch in March 2009, NASA’s Kepler probehas been staring at more than 100,000 stars in the constellations Cygnus and Lyra. As of October 2012, it had discovered some 2,300 planet candidates orbiting other stars and confirmed 77 of them. For scientists to ver-ify a discovery, the spacecraft must observe a candidate transit its parent star three times — which means finding an Earth-like planet in an Earth-like orbit around another star requires three to four years of observations. So, 2013 could mark astronomers’ first detection of a planet with earthly charac-teristics elsewhere in the cosmos.

Such a discovery undoubtedly would be one of the top science stories of 2013, but NASA and the European Space Agency (ESA) have dozens of other missions push-ing back the frontiers of science. The vener-able Hubble Space Telescope and Chandra X-ray Observatory report new discoveries every month. And newer instruments such as the Fermi Gamma-ray Space Telescope, NuStar (the first detector designed to focus X-rays), and Planck (ESA’s mission to explore the cosmic microwave background) continue to study the universe in great detail.

Although deep space holds great allure for most astronomers, planetary scientists get just as excited about missions closer to home. The biggest discoveries in 2013 likely will come from NASA’s Curiosity rover, which landed on Mars in August 2012. The mobile science lab has started exploring its home in Gale Cra-ter and soon will venture into the layered deposits of Mount Sharp. Mission scientists hope Curiosity will find evidence that Mars once had habitats with the potential to support life. Curiosity has plenty of company at Mars. As of late 2012, the Opportunity rover, Mars Express, Mars Odyssey, and Mars Reconnaissance Orbiter all were still operating on or above the Red Planet.

The other planets don’t tend to make as much news as Mars, but they remain under close scrutiny. Venus Express continues to explore our neighbor’s thick atmosphere while MESSENGER studies innermost Mercury. Farther from the Sun, Cassini keeps returning stunning images of Saturn, its rings, and its moons.

Other planetary probes are set for future stardom. The Juno spacecraft will fly past Earth in October 2013 to get a gravity assist as it heads toward a 2016 rendezvous with Jupiter. Dawn has started its trek from the asteroid Vesta to dwarf planet Ceres, where it will arrive in 2015. That year also will witness New Horizons’ arrival at Pluto for the first close-up observations of this intriguing world at the solar system’s edge.

A year of exploration

The Kepler spacecraft will continue to hunt exoplanets during 2013. This artist’s impression depicts Kepler-47, a system with two planets orbiting a binary star. NASA/JPL-Caltech/T. Pyle

NASA’s Curiosity will explore Mars’ Gale Crater throughout 2013. The rover will traverse Mount Sharp, whose layered base appears here. NASA/JPL-Caltech/MSSS

Sky Guide 2013 - Astronomy/media/Files/PDF/Sky Guide 2013.pdfmore meteors per hour under good...

Documents

Transcript of Sky Guide 2013 - Astronomy/media/Files/PDF/Sky Guide 2013.pdfmore meteors per hour under good...