2019-01-01 Astronomy

Cerberus Marmor
Sculptile
The capture of Cerberus
was the 12th and final Marmor Sculptile the
labor of Hercules. On Bust (of Christopher
this star chart, created Columbus) appeared
by Elijah Hinsdale Burritt on exactly one star
in 1835, the hero grasps chart: the 1810 A
the creature tightly. Mercator Map of the
Starry Heavens by
MICHAEL E. BAKICH LIBRARY William Croswell.

LIBRARY OF CONGRESS,

GEOGRAPHY AND MAP DIVISION

Noctua 54 Hya 4 Lib
the Owl 55 Hya
56 Hya
Once you find
Libra’s four main 57 Hya
stars, look a bit
south for the
much fainter
curved line of
five points that
formed Noctua
the Owl. TONY HALLAS

1679, French architect Augustin Royer used the head of Hercules and the head of Gladii Electorales
the same stars for Lilium the Fleur-de-lis. Cygnus, made primarily of the stars 93, 95, Saxonici
About a decade later, Polish astronomer 96, 102, and 109 Herculis. Do note that the
Johannes Hevelius re-christened that area brightest of these stars, 109 Her, glows at German astronomer Gottfried Kirch intro-
Musca, although later mapmakers who magnitude 3.9. I’ve found that the best way duced this constellation — a pair of crossed
used the figure called it Musca Borealis to to see this group is to use tripod-mounted swords — in 1684 as a political move. He
distinguish it from the far-southern con- binoculars. You don’t need much magnifi- hoped to win the patronage of Johann
stellation Musca the Fly. cation, but choose binoculars with a field Georg III, Elector of Saxony.
of view at least 7.5° wide (the distance
The Battery of Volta between 93 Her and 109 Her). The star pattern consists of nine stars
between magnitudes 3.7 and 5.2. The area
British physician and Egyptologist Thomas Felis they’re in is bounded by Arcturus (Alpha
Young designated this constellation in Boötis), Unuk al Hai (Alpha Serpentis),
1806 to honor an important invention French astronomer Jérôme Lalande sug- Zubeneschamali (Beta [β] Librae), Mu
by Alessandro Volta: the electric battery. gested this constellation in 1799 because Virginis, and Tau (τ) Virginis. Finding this
There’s not much to it, however. It’s just there was no cat in the sky. Apparently, location is easy. Making Gladii Electorales
two stars: 1 Pegasi, which glows at mag- he was thinking house cat, because three Saxonici out of its stars is not.
nitude 4.1, and 9 Pegasi, which is ever so constellations — two lions and a lynx —
slightly fainter at magnitude 4.3. Maybe already represented the feline family. It Marmor Sculptile
Young decided to represent just the bat- made its initial appearance in the star atlas
tery’s terminals? Uranographia sive Astrorum Descriptio, I wanted to include a few defunct constel-
created by German astronomer Johann lations from the Southern Hemisphere;
Cerberus Elert Bode in 1801. my first is a figure that represents the
bust of Christopher Columbus. American
In Greek mythology, Cerberus was the You can find Felis — and I warn you, its mapmaker William Croswell placed this
three-headed hound that guarded the stars are faint — by heading 30° due south star pattern on A Mercator Map of the
gates of Hades, but not against intruders. of Regulus (Alpha [α] Leonis), and trying Starry Heavens, which he produced in
Instead, he was there to prevent the dead to make a cat out of magnitude 3.8 Mu (μ) 1810. To form Marmor Sculptile, Croswell
from leaving. Hevelius included Cerberus Hydrae and a few similarly dim stars simply used the existing constellation
as part of Firmamentum Sobiescianum, sive nearby. You’ll see the constellations Corvus Reticulum with a few stars from neighbor-
Uranographia, totum Coelum Stellatum, a and Crater. Get a sense of their similar ing Horologium.
collection of star maps he created in 1687. sizes. Felis lies on the western side of Crater
opposite Corvus. Michael E. Bakich is a senior editor of
You can find Cerberus midway between Astronomy.

50 ASTRONOMY • FEBRUARY 2019

Robur Telescopium
Carolinum Herschellii

Robur Carolinum This star pattern honored the 1781
appears as a large oak discovery of Uranus by Sir William
tree on the southern- Herschel. Its creator, Maximilian Hell,
sky chart of the actually honored two of Herschel’s
1835 edition of Atlas telescopes, but Burritt combined them
Designed to Illustrate into a single constellation and placed it
the Geography of the on one of his charts. MICHAEL E. BAKICH LIBRARY
Heavens, created by
Elijah Hinsdale Burritt. Quadrans Muralis

MICHAEL E. BAKICH LIBRARY This extinct constellation appears on
Plate 10 of Urania’s Mirror by Richard
Rouse Bloxam. WIKIMEDIA COMMONS/RESTORATION BY

ADAM CUERDEN

Noctua by Jean Fortin. Johann Bode changed the Tubus Herschelii
Major and Tubus
In 1822, Scottish writer Alexander constellation’s name to Quadrans Muralis Herschelii Minor

Jamieson introduced this constellation in when he included it in his 1801 star atlas. My final entry is a pair of defunct constel-
lations. Hungarian astronomer and Jesuit
A Celestial Atlas. To create it, he used stars In the sky, locate the area that starts priest Maximilian Hell formed both in 1789
to honor Sir William Herschel’s discovery of
in far-eastern Hydra and western Libra. midway between magnitude 3.5 Nekkar Uranus. Tubus Herschelii Major commemo-
rated Herschel’s 20-foot telescope, while
But he wasn’t the first to (Beta Boötis) and magni- Minor represented his 7-foot telescope.

appropriate the stars in tude 4.6 Chi (χ) Herculis Hell placed the larger constellation in
Auriga and the smaller between Taurus and
this area. The first star and extends about 10° to Orion. He did this so they would lie on
either side of the point in Gemini where
In 1776, French maps and globes the north. If this constel- Herschel found the planet. Later maps com-
astronomer Pierre had fewer than lation’s name rings a bell, bined the two into Telescopium Herschellii.
Charles Le Monnier cre- you probably have heard To find it, head outdoors and locate Castor
(Alpha Geminorum). Telescopium
ated Turdus Solitarius, 50 constellations, it before. The radiant of Herschelii occupies a large region north of
that star in Lynx and Auriga.
the Solitary Thrush, yet despite that the Quadrantid meteor
using no less than 41 relatively small shower, which peaks The ancient sky awaits
stars between 3rd and number, some of around January 4 each
9th magnitude. You can year, lies within its (for- In Star Trek II: The Wrath of Khan,
Dr. Leonard McCoy eulogizes Mr. Spock in
find either of these birds those have not mer) boundaries. a way that can apply here: “He’s not really
of yesteryear by locating survived. dead as long as we remember him.” So,
a curved line of five Robur these constellations really aren’t extinct as
stars: 4 Librae and 54, Carolinum long as we observe them. I encourage you
to head out on the next clear night and see
55, 56, and 57 Hydrae. None other than the if you can locate one of these obscure star
figures that meant so much to so few.
Binoculars will make your task much easier great Edmund Halley created my sec-

because the brightest of these luminaries ond extinct southern-sky constellation.

glows at only magnitude 5.2. In 1679, he used some seriously bright

Quadrans Muralis stars in Argo Navis (now also gone) to
commemorate the Royal Oak where the

French astronomer Jérôme Lalande invented King of England, Charles II, supposedly

this constellation in 1795 to commemo- hid from the army of Oliver Cromwell

rate the wall-mounted quadrant at l’École after the Battle of Worcester in 1651. The

Militaire Observatory in Paris. It appeared brightest star of Robur Carolinum was

that year (as “Le Mural”) in Atlas Céleste magnitude 1.7 Miaplacidus (Beta Carinae).

CHASING LUNA’S SHADOW

IN South On the afternoon of July 2, the
Amerıca Sun will disappear along a narrow
track that stretches from Chile’s
coast to just south of Buenos Aires.

by Michael E. Bakich

This magnificent photo captures CAN YOU FEEL THE EXCITEMENT?
the diamond ring at the start
of totality July 11, 2010, from We can. Millions of people traveled to wit-
Easter Island. LES ANDERSON ness the total solar eclipse August 21, 2017,
and when it was over, many of them asked:
52 ASTRONOMY • FEBRUARY 2019 When’s the next one?

As it turns out, the next total eclipse of the
Sun occurs July 2, 2019. Its path starts in the
South Pacific near Pitcairn Island and ends
over land, having touched just two countries:
Chile and Argentina.

Totality of the 2019 eclipse will be 70 per-
cent longer than the 2017 event. This is
because Earth is not always at the same dis-
tance from the Sun, and the Moon is not
always the same distance from Earth. Since
the Earth-Sun distance varies by 3 percent
and the Moon-Earth distance by 12 percent,
the length of totality fluctuates from one
eclipse to the next. So, while the eclipse of
August 2017 had a totality lasting 2 minutes
40 seconds, the next one will be a bit longer.

Maximum eclipse, a worthy 4 minutes
33 seconds, occurs over water 665 miles
(1,070 kilometers) north of Easter Island —
and some people may travel there to experience
that length of totality. Most people who want to
see this eclipse, however, will be standing on
terra firma, and that means South America.

After you process and examine all your eclipse
images, you might want to put them together
to show how the eclipse progressed. Here, the
photographer recorded the major parts of the
total solar eclipse on August 1, 2008, from the
Ob Sea in Novosibirsk, Russia. BEN COOPER

Chile La Higuera SOUTH
Vallenar AMERICA
The central path of the Moon’s shadow first
touches Chilean soil at 19h22m38s UT, just Bella Vista ARGENTINA Buenos URUGUAY
south of the berg of Chungungo, which has Rodeo Aires
a population under 400. If you’re in that San José de Jáchal
small village, totality will last 2 minutes Montevideo
36 seconds. You’ll lose only 0.3 second off La Serena
the central path’s time.
Vicuña Villa Dolores
Some tourists will no doubt head for the
centerline in or near La Higuera, a town of San Juan Córdoba
about 4,300 inhabitants. Totality here also Path of totality
lasts 2 minutes 36 seconds. If you travel Santiago
north along Chile Route 5, La Higuera is a
five-and-a-half-hour drive from Santiago. Río Cuarto

Most travelers probably will opt to stay CHILE Junín
in La Serena, which lies only 38 miles
(61 km) south of La Higuera. With a popu- ASTRONOMY: ROEN KELLY
lation near 200,000, it’s the fourth-largest 0 300 miles
urban area in the country. There, eclipse 0 500 km
seekers will also find lodging, transporta-
tion options, fine dining (including terrific Eclipse chasers usually rely on the Anderson points out that the presence of
local cuisine), and more. And if by chance reports of Canadian eclipse meteorologist more than a half-dozen world-class obser-
you find yourself stuck in the city on Jay Anderson; he’s been predicting weather vatories in the mountains near La Serena
eclipse day, you’re not out of luck. The for eclipses of all kinds for several decades. testifies to its excellent and largely cloud-
Moon’s shadow will cover La Serena for With regard to weather prospects in Chile, free skies. July, however, is not a kind month
2 minutes 13 seconds.

CHILE CLIMATE

Station Clear Few Scattered Broken Overcast Thin fog Average cloud Sunshine Days
%
La Serena %% %% % % % with rain
Vallenar 29.2
Copiapo 16.7 11.2 26.6 16 0.4 44.7 53 2.8
Juan Fernández Islands 72.6
7.5 5 10.8 4.1 0 15.9 65 —
67.5
8.1 7.6 13.7 3 0 18.3 66 0.6
0.5
3.3 6.5 57.6 12.3 19.8 80.5 31 21

W W W.ASTR ONOMY.COM 53

particularly attractive. It’s protected from
the marine cloudiness by a range of
3,000-foot-high (1,000 meters) hills that lie
near the coast. When the coast at La Serena
is overcast, La Higuera may be clear,
although it would be unusual for clouds to
persist to eclipse time in either location.

Argentina

As the path of totality leaves Chile, it enters

Argentina. This marks the eclipse’s last

leg. The centerline actually crosses the

point where Chile Highway 41 becomes

Argentina Highway 150. And because we’re

approaching the endpoint of the eclipse, the

maximum durations of totality continue to

shrink as the path treks to the southeast.

The small hamlet of Bella Vista

The is the first place eclipse chasers
may head. There, you’ll

only time experience 2 minutes
you can view the 30 seconds of totality.
Bella Vista lies 20 miles

Sun safely with the (32 km) from the sizable
naked eye is during town of Rodeo and
50 miles (80 km) from

totality. the much larger San José
de Jáchal. The two commu-

nities have good visibility west

toward the sinking Sun (11° high

at mid-eclipse). Another option for

lodging is San Juan, which boasts a metro-

politan area of 500,000 inhabitants and lies

about 100 miles (160 km) away.

Deeper in Argentina is Río Cuarto, a

city of 150,000, which offers 1 minute

55 seconds of totality. Note: Drive just

Another way to show the eclipse from start to finish is to set up your camera centered on where north to the centerline, and you’ll gain
totality will occur, and take an exposure every few minutes. Later, you can combine them into another 20 seconds of totality. But here’s
a single image. Including a foreground object can be a nice touch. ALLAN WHETZEL the issue: At mid-eclipse, the Sun stands

just 6.3° above the horizon.

Buenos Aires offers a lot to tourists. And

there for eclipse observers or astronomers. four or more hours of sunshine, and most indeed, the southwestern outskirts of the

Observations from La Florida Airport, of these hours are in the afternoons. city do get about 50 seconds of totality. But

about 4.5 miles (7 km) inland from the These clouds usually do not penetrate a — you guessed it — the Sun at mid-eclipse

coast at La Serena, show that the city large distance inland, so an observer could stands a meager 1° above the horizon.

receives only about 53 percent of the maxi- move into a sunnier area by heading a bit For what travelers can expect from the

mum possible sunshine during the month. east. From La Serena, that would mean a weather in Argentina, we turn once again

Cloud cover is about the same, with an trip up the Elqui Valley toward the city of to Jay Anderson. He says that the available

average amount of 45 percent at 21h UT. Vicuña and beyond. While no cloud statis- evidence — satellite and ground-level mea-

(Totality is at 20h39m UT, or 4:39 P.M. local tics are available from Vicuña, the satellite surements — points to a location against

time.) Despite these somewhat pessimistic measurement of cloud cover there shows the eastern slopes of the Andes as having

statistics, a frequency graph of daily sun- an 11 percent drop compared with La the best chances of seeing the eclipse. In

shine hours for the city (see the chart on Serena. Anderson’s results suggest that the particular, Bella Vista and Iglesia to its

p. 53) shows a large number of clear or Elqui Valley might be the best spot, par- north lie on an open plain where satellite

mostly clear days. ticularly at Vicuña. Past Vicuña, the valley imagery promises the lowest average cloud

Anderson says most of the clouds at La narrows significantly, and viewers must amount anywhere along the track.

Serena come from the marine stratus that choose locations carefully to avoid the Sun July finds this region in the middle of

pushes on shore, but satellite observations being shadowed by the terrain. winter with little precipitation. But

show that the clouds typically evaporate If eclipse day promises to be sunny although the climate is dry, the terrain still

around noon. A large number of days have along the coast, La Higuera may prove has a modest effect on clouds. From a

54 ASTRONOMY • FEBRUARY 2019

Above: Wondering whether traveling halfway
across the globe to see a total solar eclipse is
worth it? Yes, it is! TONY HALLAS

Right: Wide-angle photos are on the other end
of the spectrum from close-up shots of the
diamond rings and corona. Such images convey
the sense of being at the event. TUNÇ TEZEL

ARGENTINA CLIMATE

Station Clear Few Scattered Broken Overcast Thin fog Average cloud Sunshine Days
%
San José de Jáchal 37.7 %% %% % % % with rain
San Juan Airport 37.8
Villa Dolores 39.1 22.6 14.2 16 9.4 0 31.6 61 2
Río Cuarto 35.5
Junín Airport 25.8 20.6 18.4 18.6 4.4 0.2 30.4 75 2

15.8 10.9 25.8 8.4 0 35.8 38 9

10.7 11.9 24.5 17.2 0.2 43.4 54 3

12.3 12.3 27 22.5 0.2 51.1 46 5

minimum of about 28 percent at Bella I’ve recruited several friends and eclipse equipment you’re taking and photograph
Vista, the cloud cover rises a fraction at photographers (among them Astronomy the Sun. Of course, you’ll do a few things
San José de Jáchal and then climbs more Contributing Editor Mike Reynolds), so I’m differently on eclipse day. The one to be
distinctly to 43 percent at Río Cuarto. just going to sit back and watch. We’ll sure of is that you take the solar filter off
travel in large vans, so on eclipse day we your telescope or camera lens at the start of
Bella Vista, along with Iglesia and Rodeo, can change our location if clouds intervene. totality — or, as many imagers do, just
lies in a deep, narrow, north-south tectonic prior to the first diamond ring. You’ll also
valley. The valley has a climate and geogra- Helpful advice change the exposure times once the Moon
phy comparable to that in Death Valley, hides the brilliant solar disk. Because the
California. It has one of the driest and sun- On July 2, I’ll witness my 15th total solar Sun’s corona is the same brightness as the
niest climates in Argentina. So, if you plan eclipse. I’ve written numerous stories and Full Moon, you can practice those expo-
to observe from there, make sure the even a book about these events, so I feel sures (under similar lighting) on it.
eclipsed Sun won’t slip behind a mountain. qualified to offer a few words of advice.
Finally, if you’re planning to photograph
Our plans My first point cannot be overstated: The the event and anything goes wrong . . . stop!
only time you can view the Sun safely with Just back away from your equipment and
Two editors from Astronomy are headed the naked eye is during totality. It is never watch the eclipse. The maximum duration
south to experience the eclipse. Associate safe to look at a partial or annular eclipse, of totality is a scant 273 seconds, and that’s
Editor Jake Parks will be the astronomer or the partial phases of a total solar eclipse, from a ship on the ocean. On land, it’s
for TravelQuest International, the maga- without the proper equipment and tech- about half that. Really, how many problems
zine’s partner on such trips. His group will niques. Even when 99 percent of the Sun’s do you think you can fix in two minutes?
first visit Peru, where it will tour Machu visible surface (the photosphere) is Sure, you might not get the classic shot of
Picchu, Cuzco, and other sites. At the time obscured during the partial phases of a the corona, but you’ll still have a memory
of this writing, only a few spots remain in solar eclipse, the remaining crescent Sun is that will last a lifetime.
his group, so it’s likely not an option for still intense enough to cause a retinal burn.
last-minute planners. So, protect your eyes! Michael E. Bakich is a senior editor of
Astronomy.
I’m heading to northern Chile with a Second, if you plan to photograph the
group of about 20 intrepid eclipse chasers. eclipse, rehearse. Set up the exact

W W W.ASTR ONOMY.COM 55

ABELL 21 The filaments of glowing
gas in this planetary
nebula recall the snakes
that formed the hair of
mythology’s Gorgon
Medusa, leading
astronomers to name
it the Medusa Nebula.

H. SCHWEIKER (NOAO/AURA/NSF)

AND T.A. RECTOR (UNIVERSITY OF

ALASKA-ANCHORAGE/NOAO/AURA/NSF)

you can use Dip into these lesser-known
catalogs for a look at some
different deep-sky wonders.

by Alan Goldstein

TRUMPLER 2 TRUMPLER 3 TRUMPLER 5

A magnitude 7.4 orange giant star anchors this This youthful group of some 570 stars looks much This tightly packed cluster of 150 stars lurks just
group of about 20 stars in Perseus. MARTIN C. GERMANO sparser through amateur scopes. MARTIN C. GERMANO west of the Cone Nebula in Monoceros. CHUCK KIMBALL

Ever since humans first looked up ARP 157
at the night sky, they have felt
compelled to record what they saw. A pair of spiral galaxies started to collide about 300 million years ago, creating this peculiar galaxy
The Babylonians of Mesopotamia that one day will become a single elliptical. NASA/ESA/THE HUBBLE HERITAGE TEAM (STSCI/AURA)/B. WHITMORE (STSCI)
compiled the first known star cata-
log more than 3,100 years ago, and other (POSS) was the first systematic attempt eventually became the Trumpler catalog.
ancient civilizations followed with their to photograph the entire sky visible from Although most of these clusters tend to be
own star catalogs. All were limited to what a single location (California’s Palomar overlooked, a few are true gems.
the naked eye could see. Mountain). Astronomers used hand lenses
The telescope’s debut 400 years ago to study the black dots and blobs that Trumpler 2 is a scattering of 20 stars
revealed objects invisible to the naked eye. appeared on the large photographic plates. about 2.5° southeast of the Double Cluster
As the universe began to unfold, astrono- in Perseus. This small collection glows at
mers developed new catalogs to record In the second half of the 20th century, 6th magnitude across a distance of more
their observations. large low-cost optics became available to than 2,000 light-years. Its brightest mem-
In the 18th century, French comet- amateur astronomers, and fainter, more ber is the orange star SAO 23469.
hunter Charles Messier created the first obscure objects grew popular. Observers
account of deep-sky objects that included turned to newer catalogs to tackle objects Trumpler 3 lies 8.6° east of the 3rd-
both locations and descriptions. He did that many folks a generation earlier had magnitude star Epsilon (ε) Cassiopeiae.
it to avoid “rediscovering” previously thought impossible to see. Completing these At first glance, it shows about 30 stars in a
observed faux comets. His list soon became catalogs became badges of honor for ama- 23' field, but astronomers have discovered
the catalog of choice for amateur astrono- teurs seeking targets that few had seen. some 570 members in total. Researchers
mers because the clusters, nebulae, and estimate the 7th-magnitude cluster formed
galaxies it contains are bright and varied. Many obscure catalogs have now only about 70 million years ago, during
The objects also covered most of the sky become mainstream. Some of the objects Earth’s Late Cretaceous period.
visible from mid-northern latitudes. they contain are easy, while others require
In 1888, Danish-Irish astronomer large scopes and superb skies. Let’s take a Trumpler 5 resides just west of the
John Louis Emil Dreyer compiled the next look at some of my favorite examples. Cone Nebula (part of the NGC 2264
astronomical standard: the New General complex) in Monoceros. This rich cluster
Catalogue. (For a more complete story on Open clusters contains some 150 stars packed in an area
this catalog, see “An NGC primer” in the 7' across, but the 11th-magnitude object
September 2018 issue.) Based on visual Robert Trumpler studied open star clusters glows faintly enough that you’ll need large
observations, the NGC was the main in the early 20th century to learn their dis- optics for a good view. This ancient cluster
source for non-stellar celestial objects tances, sizes, and distribution in the Milky lies in the direction opposite to our galaxy’s
for more than 60 years. Even today, it Way. He investigated 100 clusters, 37 of center and appears to be between 3 billion
remains the preferred catalog for serious which were unknown at the time and and 4 billion years old.
deep-sky observers.
Photography gradually replaced the
astronomer’s eye in the second half of the
19th century. And as telescopes grew up
to 200 inches in aperture in the 1940s, the
universe started to reveal its secrets at an
astonishing rate. The National Geographic
Society-Palomar Observatory Sky Survey

W W W.ASTR ONOMY.COM 57

ARP 84 ABELL 262

These interacting spirals are in the early stages of colliding. A few billion years from now, they’ll This rich galaxy cluster contains a surprisingly
merge into a single boring elliptical galaxy. ADAM BLOCK/MOUNT LEMMON SKYCENTER large number of spirals. It forms a small part of
the vast Perseus-Pisces Supercluster. MARK MANNER

ARP 22 Peculiar galaxies Arp 85). Arp 84 is visible through modest
telescopes, though larger apertures reveal
A lone extended spiral arm and an asymmetrical Halton Arp’s famous 1966 Atlas of Peculiar more detail. NGC 5394 is a magnitude 13.0
disk qualify this galaxy as peculiar. ESO Galaxies remains a favorite of deep-sky compact spiral measuring 1.7' by 0.7' with
observers. Many of the catalog’s 338 objects two faint, elongated arms. Glowing at
ARP 214 are bright (a few are Messier objects), while magnitude 11.7, NGC 5395 is bigger (2.7'
others pose a challenge for big apertures. by 1.2') and has one arm sweeping in front
A galactic collision produced this odd-looking Although Arp considered these galaxies of its disk.
object (at right) that seems to be part edge- peculiar for the way they looked, astrono-
on and part face-on spiral. Directly south of mers now realize most are interacting or George Abell:
it (below) lurks the tangled mess of galaxies colliding galaxies. As such, they often look master list creator
cataloged as Arp 322. DIETMAR HAGER intriguing through a telescope.
Caltech graduate student George Abell
58 ASTRONOMY • FEBRUARY 2019 Arp 157 (NGC 520) ranks among the was among the first people to study the
more unusual objects in Pisces. This edge- POSS plates after they were developed. As
on pair of colliding galaxies looks like a a result, he had first dibs on looking for
triangular door wedge. Glowing at magni- new objects. His efforts produced three
tude 11.4 and measuring 4.6' by 1.7', the lists of different objects: planetary nebulae,
object shows up through 8-inch scopes. globular star clusters, and galaxy clusters.
He published the first two in 1955; the
Arp 22 (NGC 4027) is a barred spiral 1957 galaxy cluster catalog served as his
galaxy with a single extended arm that Ph.D. thesis.
looks like a comma through amateur tele-
scopes — definitely not a typical spiral! Planetary nebulae
This 11th-magnitude denizen of Corvus
spans 3.8' by 2.3'. Its strange appearance Abell 12 is the easiest of the Abell plan-
likely arises from a collision with a smaller etaries to find because it lies just 1.2'
galaxy millions of years ago. west-northwest of 4th-magnitude Mu (μ)
Orionis. Like all low-surface-brightness
Arp 214 (NGC 3718) lies 3.2° west of planetary nebulae, an Oxygen-III filter
Gamma (γ) Ursae Majoris. A distorted increases its contrast with the background
spiral with a large dust lane arcing across sky and makes it easier to see. This Sun-
the middle of the disk, Arp 214 combines like star’s death shroud spans 40".
features of a face-on and edge-on galaxy.
Shining at magnitude 10.7 and measuring Abell 21, better known as the Medusa
10' by 4.7', it is large and easy to observe. Nebula, resides in southern Gemini near
NGC 3729 is a smaller spiral to the east the constellation’s border with Canis
that likely collided with NGC 3718. Minor. This crescent-shaped nebula mea-
Arp 322, a complex group of galaxies also sures about 10' by 6', which translates into
cataloged as Hickson 56, lies 7' south of a physical diameter of 4 light-years, plac-
Arp 214 and in the same field of view. ing Abell 21 among the oldest known
planetaries.
Arp 84 (NGC 5394-5) is a wonderful
pair of interacting galaxies often over- Abell 39 in Hercules is a ghostly cloud
looked in favor of its neighbor in Canes of ionized gas in the shape of an almost
Venatici, the Whirlpool Galaxy (M51,

PALOMAR 6 ABELL 39

It’s hard to identify this 12th-magnitude globular The circular form of this planetary nebula caught the eye of George Abell as he examined photographic
cluster against the rich backdrop along the plates from the National Geographic Society-Palomar Observatory Sky Survey. WIYN/NOAO/NSF
Ophiuchus-Sagittarius border. DANIEL B. PHILLIPS

perfect circle spanning 2.6'. Like many Helen Sawyer Hogg probably deserves PALOMAR 8
Abell planetaries, it is a challenge, but the credit for giving them the “Palomar”
observers with an 8-inch scope under name. Thirteen of these 15 clusters were This compact, 11th-magnitude globular star cluster
a dark sky can see it. unknown to astronomers of the mid- stands out quite well despite the myriad stars in
1950s. They are not easy to observe this part of Sagittarius. ANTHONY AYIOMAMITIS
Galaxy clusters because they have low surface bright-
nesses, and interstellar matter obscures PALOMAR 11
Abell’s catalog of rich galaxy clusters ini- many of them. The three targets I’ll high-
tially contained 2,712 entries. After Abell light are among the toughest objects in Plan to use a large scope to find this challenging
died in 1983, Harold Corwin and Ronald this article. Seek them under the most globular cluster, whose light spreads across a
Olowin continued the survey in the transparent skies you can get. diameter of nearly 10'. ANTHONY AYIOMAMITIS
southern sky. They added 1,361 clusters,
bringing the total to 4,073. Palomar 6 rates as one of Ophiuchus’ W W W.ASTR ONOMY.COM 59
most challenging clusters. Embedded in
Abell 262 glows at 13th magnitude a rich star field on the constellation’s bor-
and is one of several galaxy clusters in der with Sagittarius, Palomar 6 is large
Andromeda visible through modest tele- (7.2' across), faint (magnitude 11.6), and
scopes. It holds seven NGC objects and diffuse. It is one of four globulars known
dozens of fainter galaxies in a compact to harbor a planetary nebula, a 16th-
field. Unlike most rich galaxy clusters, magnitude object that spans 8" on the
Abell 262 has a high percentage of spirals. cluster’s north side.
It belongs to the enormous Perseus-Pisces
Supercluster, which includes the Perseus Palomar 8 in Sagittarius shines at
Cluster (Abell 426). magnitude 11.0, making it one of the
list’s brighter clusters. A round glow mea-
Abell 1367, the Leo Cluster, dwells suring 4.7' across, Palomar 8 lies 2.4° east-
5.5° north of 2nd-magnitude Denebola. southeast of the bright open cluster M25.
The brightest cluster member, the mag-
nitude 11.8 elliptical galaxy NGC 3842, Palomar 11 lies 2.3° east-southeast
possesses a central black hole with a of 5th-magnitude Kappa (κ) Aquilae.
mass of nearly 10 billion Suns, making Although Palomar 11 glows at 10th mag-
it one of the most massive black holes nitude, that’s deceptive because its light
known. This spiral-rich cluster appears is spread over a diameter of nearly 10'.
more than three times the diameter of the
Full Moon, so you’ll want to use a wide- I hope this article entices you to
field eyepiece to explore it. Many of the explore the tip of an astronomical iceberg.
targets glow brighter than 13th magni- You can find plenty more specialized cata-
tude; the challenge comes in identifying logs online. Look for names like Collinder,
each object. Hickson, Sharpless, and Terzian — these
are just a few that await discovery as you
Palomar globular clusters expand your universe.

Although Abell created this list, several Longtime deep-sky observer Alan Goldstein
other astronomers helped find these
globulars on the POSS plates, and has been writing about distant objects

for Astronomy since 1981.

We test Coronado’s
latest

A sleek look, easy operation, and a
tunable filter make the SolarMax III
one to consider. by Raymond Shubinski

When I was director Out of the box A double-stack with a 400mm focal length. The
of the East Kentucky Hydrogen- actual solar filters are mounted on
Science Center in Those of us who own quality alpha filter sits front of the tube assembly, making
Prestonsburg, Kentucky, equipment know the impor- at the front of this an incredibly versatile telescope
we created an outreach program with a tance of good storage. The the telescope.
mobile observatory. Because the program
went to schools in the daytime, we needed SolarMax III case is made of MEADE INSTRUMENTS — but more about that later. As
solar scopes.
aluminum with metal reinforc- with all solar scopes, SolarMax III
So I visited Coronado Telescopes in
Tucson, Arizona. At the time, it made ing bands across all the edges, and addi- lets you directly and safely observe the
the best small solar telescopes available.
When I entered the workshops, I was tional reinforcement on each corner. The Sun’s chromosphere in real time. Unlike
immediately struck by the people and
products I encountered. The attention aluminum panels on the case are anodized common full-aperture, white-light solar
to detail, craftsmanship, and precision
were obviously paramount. black, while all the reinforcing bands are filters, which allow you to safely view a

The solar scopes I purchased for the finished in brass. This carrying case looks combination of all of the Sun’s visible light,
Science Center performed flawlessly.
Needless to say, that meant I was excited like a piece of luxury luggage; it was cer- the SolarMax III provides views of our
to receive the new 70mm SolarMax III
telescope to inspect, use, and review. tainly built to protect the telescope inside. daytime star specifically in the Hydrogen-

Opening the case reveals the SolarMax alpha (Hα) wavelength.

telescope nestled in the fitted interior Meade produces the SolarMax with

foam. The finish on the scope is a combi- either a single and double stack of filters;

nation of brass and black anodization. this refers to the number of etalon filters

It looks great and reminds me of a fine supplied on the instrument. (Etalon is a

19th-century instrument. French word for “standard.”) These filters

SolarMax III is, in fact, a 2.75-inch were developed over a hundred years ago

(70 millimeters) f/5.7 refracting telescope and remain the standard for this type of

60 ASTRONOMY • FEBRUARY 2019

equipment. The review telescope has a second etalon filter. You adjust The SolarMax III knobs that tune the etalon filters.
double-stack configuration, which gives these to fine-tune the etalons is an impressive It was easy to get a fantastic 3D
finer control of tuning and, thus, reveals and thus bring out additional telescope, optically image. Some features on the Sun
more detail. details. Meade also placed a and mechanically. are moving toward or away from

The Sun produces energy all across the MEADE INSTRUMENTS
electromagnetic spectrum. It’s like the
Sun’s total energy output being all the keys blocking filter in what looks Earth. Light undergoes a
on a piano played at once. Hα, then, is just
a single key. Wavelengths are measured in like a star diagonal, which is Doppler shift as a result. The
angstroms or nanometers. That of Hα is at
6562.8 A or 656.28 nm. Etalon filters are attached to a tube that fits in the focusing T-Max Tuners adjust the etalon filters to
designed to eliminate all but this single line
of energy. rack. The blocking filter eliminates more help compensate for this visual Doppler

Using the scope wavelengths of light and produces an image shift. The end result is amazing contrast

The tripod didn’t come with the scope, that’s safe to look at. and detail.
but that wasn’t a problem. The unit comes
with a standard dovetail mounting rail, It takes some practice to get the best When observing with the SolarMax III,
which works on most telescope mounts.
Once I attached the telescope to the visual image through this scope. The solar features normally only seen in profes-
equatorial mount on my tripod, I set the
SolarMax III out under the desert Sun. SolarMax III is fitted with a high-quality 2" sional images are visible. At the time I used

I’ve often been asked why I need a dual-speed rack and pinion focuser, which this telescope, the Sun was relatively quiet.
finder scope to locate the Sun. It’s not as
easy (or safe) as most people think — it’s allows for both coarse and fine adjust- The chromosphere had a distinct mottled
not like you can look through the scope or
even sight down its tube. But on this scope, ments. I had to pull the blocking filter with (grainy) look. At times, I could see promi-
Meade’s 3½-inch-long brass SolRanger
Sun finder is firmly attached to the upper its tube about halfway out to get the best nences looping up from the Sun’s edge. By
mounting ring. This little gadget allows
sunlight to fall on a small piece of ground focused image. Then I adjusted the playing with the T-Max Tuners, I was able
glass at its back end. There’s no need to
look through the SolRanger. Just adjust the RichView Tuner. to achieve a definite 3D effect that was
telescope until you center a small bright
dot of sunlight on the glass. When I first looked though the eyepiece, astounding.

Using a solar telescope isn’t as straight- I saw several secondary solar images. Bonus!
forward as a regular scope. The various Rotating the tuner helped move these to
filters need “tuning” to get the best image.
The SolarMax III comes with a CEMAX where they weren’t noticeable. While still As I mentioned, the SolarMax III is a
18mm 1¼" eyepiece. Any standard 1¼" eye-
piece will work, but the Coronado CEMAX watching the image, I worked the two small basic refracting telescope with its front
eyepieces are specially designed and coated
for Hα wavelength. end loaded with filters that allow you

Four filters in this telescope make it to view the Sun. But if you unscrew the
possible to safely observe the Sun in the
Hα wavelength. When you remove the PRODUCT INFORMATION etalon filter section, remove the blocking
front dust cap, you’ll see that the objective filter, and replace it with a star diagonal
lens is red. This is where the filtering
starts. The red objective reduces or (all quite simple to do), you end up with a
“rejects” most of the light energy entering
the telescope. SolarMax III quite normal optical telescope to view the

Directly behind the objective is the Aperture: 2.75 inches planets or Moon. In fact, if you so desire,
RichView Tuner, which sits in front of the
first etalon filter. The tuner (it’s not a filter) Focal length: 400 millimeters you can place a Meade 2" Solar White-
is mounted in a large brass ring and can be
rotated to improve contrast and detail. An Focal ratio: f/5.7 Light Herschel Wedge in the focusing
inch or so behind the tuner is a small brass
knob on the first etalon filter. This is one Focuser: 2" two-speed rack and pinion rack, making this a nice white-light solar
of two T-Max Tuners. There is a second
T-Max Tuner knob farther back at the Dimensions: 19.3 by 5.9 by 5.5 inches telescope. Talk about versatile!

(49 by 15 by 14 centimeters) Meade Instruments bought Coronado

Weight: 9.3 pounds (4.2 kilograms) Telescopes some time after my visit to its

Comes with: Vixen-style dovetail, shop. Having used the SolarMax III

CEMAX 18mm 1¼" eyepiece, telescope, I can see that the dedication to

SolRanger Sun finder quality and precision has not changed. In

Price: $2,299 fact, after using this scope, I’d say that

Contact: Meade Instruments these qualities not only have remained,

27 Hubble but also improved.

Irvine, CA 92618

800.626.3233 Raymond Shubinski is a contributing editor

www.meade.com of Astronomy who views the Sun often under

the cloudless skies of Las Vegas.

W W W.ASTR ONOMY.COM 61

OBSERVINGBASICS θ1 Orionis B
θ1 Orionis A
BY GLENN CHAPLE
θ1 Orionis D
Experience the θ1 Orionis C
Orion Nebula

It’s so visually stunning, you could almost sing its praises.

What’s the top- — you experience it! I suggest
ranked nebula in
the entire night doing that in three stages: first
sky? The No. 1,
must-see target with your unaided eyes, then
for the backyard astronomer?
By sheer grandeur, the hands- with binoculars, and finally
down winner would be the
Carina Nebula. However, I can through a telescope.
only guess at its visual splendor
because it lies at a declination A naked-eye view of the
of –60° and I’ve never had the
fortune to travel far enough Orion Nebula from a dark site Embedded within Orion the Hunter is the Orion Nebula (pictured), which, in turn,
south to spot it. allows us to admire its name- contains a tight cluster of stars known as Trapezium (inset). NASA, ESA, M. ROBBERTO (STSCI/ESA),
sake constellation — arguably
For that reason, I would cast AND THE HUBBLE SPACE TELESCOPE ORION TREASURY PROJECT TEAM; INSET: THEOFANIS N. MATSOPOULOS
my vote for the Orion Nebula.
It’s smaller and fainter than the the grandest of all. Orion the
Carina Nebula, but it’s just 5°
south of the celestial equator, Hunter consists of an 18°-by-11° star Iota (ι) Orionis is the wide by the French astronomer Jean-
making it accessible to virtually
anyone on the planet. It’s a neb- lopsided rectangle formed by double star Struve (Σ) 747, Jacques d’Ortous de Mairan
ula for everyone!
four bright stars framing a dis- whose magnitude 4.7 and 5.5 and later became the 43rd entry
Before I sing a paeon to the
beauty and wonder of Orion’s tinctive diagonal row of three components are 36" apart. It’s in Messier’s catalog.
Great Nebula, let me lay out a
few nuts-and-bolts facts. The more recognizable luminaries. interesting to note that Galileo The visual impact of the
Orion Nebula is classified as an
emission nebula — a cosmic Each of these seven stars ranks himself observed and mapped Orion Nebula is so overwhelm-
cloud of dust and gas that
shines by emitting its own light. among the 70 brightest in the the Sword but failed to see the ing that we initially overlook an
Recent studies place its distance
at about 1,300 light-years. Its night sky. Two of them — 1st- Orion Nebula. The magnifying amazing little quartet of stars
apparent size of 1½° by 1° trans-
lates to a true diameter of some magnitude Betelgeuse and Rigel power of his telescope was com- embedded in the nebulosity and
25 light-years. The nebula’s dis-
covery is credited to the French — are in the top 10. The myth- parable to that of modern-day best seen with a magnification
astronomer Nicholas Peiresc,
who spotted it in 1610. Charles ological Orion was an imposing binoculars, but its ¼° field of of 75x to 100x. This is the
Messier observed and cataloged
it the night of March 4, 1769, figure, and his namesake con- view would have been too small Trapezium, a tight cluster of
designating it M42.
stellation is no less impressive. to encompass the nebula. stars birthed by the Orion
On second thought, maybe
I’ll pass on “An Ode to the Nebula. Small scopes reveal the
Orion Nebula,” as music and
words fail to adequately capture A naked-eye view of the Orion four stars — magnitudes 5.1,
its visual grandeur. You don’t Nebula allows us to admire its namesake 6.4, 6.6, and 7.5 — that make up
just observe the Orion Nebula the group. The brightest of these

constellation — Orion the Hunter. four suns is Theta1 (θ1) Orionis
C. Larger instruments will add

a pair of 11th-magnitude stars

Hanging vertically from the A telescope places the Orion to the mix. Although some may

three-star row (Orion’s Belt) is a Nebula at center stage — no question the choice of M42 as

fainter three-star chain (Orion’s competition from constellations the sky’s finest nebula, there is

Sword). Look at the middle or immediate surroundings! no doubt that the Trapezium

member. It seems hazy. Is it the Even a common 2.4-inch refrac- is the heaven’s most beautiful

nebula, or is it an illusion? tor magnifying at just 30x to multiple star.

Binoculars allow us to key in 50x captures impressive detail. Questions, comments, or

on the Sword and its surround- Nebulous wreaths branch out- suggestions? Email me at

ings, proving that the haze at its ward like the open wings of a [email protected]. Next

center is not an illusion after ghostly eagle. Larger scopes month: I correct an error I

all. This hazy, puffy ball is a reveal a mottled, almost chaotic, made in The Edmund Scientific

definite attention-getter, but it texture and an overall greenish Mag 6 Star Atlas. Clear skies!

has competition from its sur- color. Just north of the Orion

roundings. A degree to its Nebula is a 7th-magnitude star Glenn Chaple has been an
north is the open cluster NGC surrounded by haze. This avid observer since a friend
1981. At the bottom of the detached portion of the Orion showed him Saturn through a
Sword and next to the bright Nebula was discovered in 1731 small backyard scope in 1963.

BROWSE THE “OBSERVING BASICS” ARCHIVE AT www.Astronomy.com/Chaple.

62 ASTRONOMY • FEBRUARY 2019

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W W W.ASTR ONOMY.COM 63

BINOCULARUNIVERSE

BY PHIL HARRINGTON

Treats in Taurus

This is no bull — just great deep-sky observing.

Iclosed last month’s col- and even though the Sun was The Crab Nebula is one of the great supernova remnants in the sky, but it is relatively
umn, which discussed nearby at the time, it was visible small and faint for binocular users. R. JAY GABANY
some off-the-beaten-path in broad daylight for more than
targets in Taurus, with the three weeks. Halfway around snowbank. As I scanned back magnitude, M35 can be
promise that we would the globe, drawings attributed to and forth through those bin- glimpsed by eye alone on the
return to the Bull this month Anasazi and Mimbre Native oculars, I decided to see just darkest nights. But it takes bin-
in search for the corpse of a American artists also captured how many Messier objects I oculars to expose the true
star that died millennia ago. its appearance. Strangely, there could find. It seemed appropri- beauty of this object. Even when
That stellar corpse is none are no records that anyone in ate to start at the beginning, so used under moderate suburban
other than the famous Crab Europe, just emerging from the I aimed toward M1. Sure light pollution, most 7x and 10x
Nebula (M1), one of the most Early Middle Ages, took notice enough, it was there! It wasn’t binoculars resolve the brightest
fascinating objects found any- of the event. obvious, but I could definitely dozen or so cluster stars from
where in the heavens. When make out a tiny smudge right the misty glow caused by
he first happened upon it Today, of course, we know where I knew the Crab lurked. another 200 fainter suns that
August 28, 1758, Charles that they witnessed a super- make up this outstanding stellar
Messier mistook it for a comet. nova, the final hurrah of an I bet that you can do it, too, gathering.
This singularly important obser- extremely massive star. All that if you wait for an exceptionally
vation ultimately led to his now- is left is an expanding cloud of clear night. Aim your binocu- Just southwest of M35 is the
famous list of deep-sky objects. gaseous debris and, buried deep lars toward the star Zeta (ζ) very rich and very distant open
But Messier was not the first within, the rapidly beating Tauri, marking the Bull’s east- cluster NGC 2158. Studies show
person to lay eyes on the Crab. heart of that ancient star, the ern horn. Now look for two that M35 is 2,800 light-years
That moment went to London Crab Nebula pulsar. fainter stars just to Zeta’s north away, but NGC 2158 is nearly
physician John Bevis, who had that together form a tiny tri- 16,000 light-years distant.
discovered it 27 years earlier. I can still remember the cold angle. Finally, without moving
The Crab’s impact on our January night back in high your aim, shift your eyes from NGC 2158 is usually listed
view of the universe began long school when I first spotted the those two dim suns about ½° to as between magnitudes 8.5
before that, however. On July 4, Crab through my original 7x35 the west. That’s where M1 lives. and 9 in observing handbooks,
1054, Chinese astronomers binoculars. At the time, I con- Please drop me a line through but I have always felt this is
studying the early predawn sky sidered it to be a reasonably my website if you see it. a bit optimistic. I can see it
suddenly noticed a brilliant star easy catch using my 8-inch through my 10x50 binoculars
where no star previously existed. reflector, but impossible One of my favorite winter if steadily supported, but only
It outshone the planet Venus, through binoculars that small. open clusters is little more than on the best nights.
One evening, I was out in my a binocular field to the east-
backyard, literally lying in a northeast of Zeta Tauri, across There’s a third open cluster
the border in Gemini. M35 is in the same binocular field
RICHARD MCCOY much brighter and easier to find as M35, although few pay it
than the Crab. Look for it near much attention. Lying about
Binocular sweeps in Gemini will unveil M35, one of the winter sky’s brightest open the stars that form the foot of midway between M35 and Mu
clusters (center), and the more distant cluster NGC 2158 as a fainter glow (bottom). the twin Castor. Trace his body Geminorum, Collinder 89 is
down from his namesake star a sparsely settled collection of
toward his ankle and foot, about 15 suns. Only four, how-
which are marked by an arc of ever, are apparent through
three stars, Mu (μ), Eta (η), and binoculars: 9, 10, 11, and 12
1 Geminorum. M35 lies to the Geminorum. This slender
northwest of Eta. Its position diamond of stars helps define
near Castor’s big toe leads me to the span of this obscure open
think of this as the “Soccer Ball cluster.
Cluster,“ as it looks like Castor
is about to kick it right between Phil Harrington is a longtime
the horns of Taurus. contributor to Astronomy and

Shining at about 5th the author of many books.

64 ASTRONOMY • FEBRUARY 2019

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W W W.ASTR ONOMY.COM 67
The Advertiser Index is provided as a service to The Accretion Theory. The Theory of Relativity was also
Astronomy magazine readers. The magazine is not disproven when it was discovered that the speed of light is
responsible for omissions or for typographical errors in the fastest speed that there is and therefore the “c (speed of
names or page numbers. light)” in E=mc2 cannot be squared. A $25,000.00 Reward

is offered to the first person to disprove The AP Theory.

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ASKASTR0 Astronomy’s experts from around the globe answer your cosmic questions.

NO RETURNS HELIOSHEATH VOYAGER 2
TERMINATION SHOCK August 30, 2007
Q: PAGE 13 OF THE JULY 2018 ISSUE STATES
THE SOLAR SYSTEM’S ESCAPE VELOCITY IS NEPTUNE Crosses the
1,381,308 MPH. THE VOYAGER SATELLITES termination shock
ARE NOT GOING THAT SPEED BUT APPEAR URANUS
HEADED OUT OF THE SOLAR SYSTEM. VOYAGER 1
SHOULD WE EXPECT THEM TO RETURN? SATURN February 17, 1998
Becomes the most distant
Mark Lampe, St. Louis, Missouri human-made object

A: Both Voyagers are on one- from the Sun. The escape veloc- VOYAGER 1 VOYAGER 1
way tickets out of the solar sys- ity was thus 30,400 mph (49,000 December 16, 2004 August 25, 2012
tem. But, as you note, neither is km/h), well below the probe’s Passes the reach
traveling anywhere near exit velocity of 49,000 mph Crosses the of the solar wind
1,381,308 mph (2,223,000 (79,000 km/h). Today, the dis- termination shock
km/h). The apparent inconsis- tant spacecraft is still traveling at
tency arises because escape 38,000 mph (61,000 km/h) and Launched in 1977, Voyager 1 (blue) has exited the solar system, with
velocity depends on where you leaving the solar system at nearly Voyager 2 (red) to follow. To leave the solar system, the Voyagers only
start your journey. five times the escape velocity of needed to reach the escape velocity at the last planet from which a gravity
7,900 mph (12,700 km/h). assist was received: Saturn and Neptune, respectively. ASTRONOMY: ROEN KELLY
A handy formula for calcu-
lating escape velocity is Richard Talcott particles — as well as X-rays and and that is precisely why we
Senior Editor gamma rays (both highly ener- study it.
2GM getic forms of light). These can
υ esc R Q: IS IT POSSIBLE be extremely penetrating and Our ignorance is a conse-
TO PASS THROUGH A can damage, or microscopically quence of the fact that the tem-
where vesc is the escape velocity, 4 MILLION-DEGREE CLOUD burn, cells and electronics. On perature (or, equivalently, the
G is the gravitational constant, OF INTERSTELLAR GAS Earth, the atmosphere and mag- energy) of everything in the
M is the mass of the object WITHOUT BURNING UP? netosphere largely protect us early universe exceeds, by far,
you’re leaving, and R is the dis- from cosmic rays. Some lethal those that we can probe experi-
tance from the center of that Launie Wellman radiation is still present, but it is mentally in even the most
object. The diagram and Fast Festus, Missouri emitted mostly from rocks and advanced laboratory. However,
Fact in the July issue assumed soils — no cause for concern, as we have strong reasons to
you were escaping from the A: Four million degrees indeed long as the radiation dose is low. believe that the four fundamen-
object’s surface, so R is simply sounds like a burningly high Here again, the density matters! tal interactions that govern how
the radius. temperature. However, for a matter behaves — the strong,
body to actually burn requires Daniel Wang weak, electrical, and magnetic
If you’re trying to leave the not only a high enough tem- Professor of Astronomy, interactions — are all manifes-
solar system from Earth’s orbit, perature, but also a sufficiently University of Massachusetts, Amherst tations of a single underlying
however, R is about 93,000,000 dense gas cloud. Interstellar physical mechanism that occurs
miles (150,000,000 km; the dis- space is mostly empty, especially Q: HOW CAN WE DETERMINE only at these extreme tempera-
tance of Earth from the Sun) in hot gas clouds, more so than THAT INFLATION OCCURRED tures. As the universe expanded
and not 432,000 miles (695,500 any vacuum produced on Earth. FROM 10-35 TO 10-32 SECOND and cooled, the strong and
km; the Sun’s radius, as used in Such a cloud simply does not AFTER THE BIG BANG, AND electro-weak interactions (this
the figure), so the escape veloc- have the heat or energy density THAT THE UNIVERSE GREW refers to the weak, electric, and
ity is only about 94,000 mph (a term that refers to the amount 1026 IN THAT TIME? magnetic interactions together)
(151,300 km/h). Further, for an of energy available in the gas per underwent a phase change,
interplanetary spacecraft, its unit volume) high enough to Louis Lessinger which means they split apart
escape velocity from the solar effectively burn a human body, Plainview, New York and became distinct.
system is the escape velocity at let alone a spaceship. So the
the last planet it received a grav- high temperature is not a con- A: The answer is the combina- It is not known exactly (i.e.,
ity assist from. Take Voyager 1 cern for interstellar travel. tion of a big extrapolation and through direct experimental
as an example: It encountered an even bigger assumption, evidence) how this process pro-
Saturn in November 1980, when However, one does need to based on a solid hunch and the ceeded, but by comparison with
the ringed planet was about consider cosmic rays — high- surety of our ignorance regard- other phase changes we can
890 million miles (1.4 billion km) energy subatomic charged ing what was really going on. probe, it is thought possible that
The truth is, everything about this strong/electro-weak phase
the early universe is speculative, transition (splitting) could drive
the period of inflation. The time

68 ASTRONOMY • FEBRUARY 2019

period you reference (10-35–10-32 involved with the invention of The Andromeda Galaxy is speeding toward us, but it will take 4 billion
second) is directly tied to the the inflationary paradigm in years to get here. This artist’s concept shows the night sky from Earth
temperature at which this phase the first place (e.g., Paul in 3.75 billion years: Andromeda is much closer, appears larger, and
transition was thought to occur. Steinhardt, Neil Turok), find has begun to distort the plane of the Milky Way with its gravitational pull.
inflation to be so contrived and
It is important that observa- finely tuned that it cannot be a NASA, ESA, Z. LEVAY AND R. VAN DER MAREL/STSCI, T. HALLAS, AND A. MELLINGER
tional facts be differentiated viable ultimate theory of the
from theory or speculation. early universe. out how fast Andromeda is straight for us, or is it aimed off
Although inflation does not yet moving. We do this by observ- to the side? Right now, we know
fall within the realm of obser- William Jones ing the galaxy and comparing that if there is any offset, it’s
vational fact, many of its poten- Associate Professor, what we expect to see from a pretty small (less than the size
tial implications do. I’ll list Department of Physics, Princeton galaxy at rest to what we actu- of a pixel on the Hubble Space
just a couple: We observe cor- University, Princeton, New Jersey ally see from Andromeda. Telescope’s detector). However,
relations in the cosmic micro- Things moving away from us even a small angle between
wave background (CMB) that Q: THE ANDROMEDA have light that is Doppler Andromeda and the Milky Way
are acausal; fluctuations in GALAXY IS MOVING shifted toward the red end of will affect when and how the
temperature that occur at two TOWARD THE MILKY WAY the spectrum; things moving two galaxies collide, which stars
points in space so far apart that FROM 2.5 MILLION LIGHT- toward us have light shifted will be flung out of the galaxies,
light could not travel between YEARS AWAY. TODAY, WE SEE toward the blue. and which will stay in. Think
them in the lifetime of the uni- IT AS IT WAS 2.5 MILLION about playing golf or baseball
verse are found, empirically, to YEARS AGO. WOULDN’T ITS Based on Doppler shifting of or tennis — the movement of
be highly correlated. Also, ACTUAL POSITION BE its light, Andromeda is speeding the ball changes when you don’t
there is a characteristic scale 2.5 MILLION LIGHT-YEARS toward us at 68 miles per sec- hit it head on.
associated with these fluctua- CLOSER, AND SHOULDN’T IT ond (110 kilometers per second).
tions, measured by both the BE COLLIDING WITH OUR Compare this to the light from Unless something radically
WMAP and Planck satellites, GALAXY NOW? Andromeda, which is moving changes Andromeda’s course,
that is too large to explain toward us at 186,000 miles per current estimates say that we’re
unless inflation occurred. Bill Gerhold second (300,000 km/s). only about 4 billion years from
Finally, our universe currently Hewitt, New Jersey a catastrophic collision that
seems to be undergoing some- So how much closer to colli- will leave us inside a merged
thing like the inflation that A: Ever since we could measure sion with Andromeda have we remnant of what was once two
people imagine in the early the movement of Andromeda, come in the past 2.5 million separate galaxies.
universe. By some bizarre we’ve known it was on a colli- years? If we assume Andromeda
coincidence it seems to have sion course with the Milky has been moving at the same Valerie Mikles
started about the time our solar Way. Fortunately, a galaxy is speed without accelerating,
system formed, some 5 billion much heftier than a photon, then in the last 2.5 million National Oceanic and Atmospheric
years ago. and it is not flying toward us at years, Andromeda has moved
the speed of light, so we have a only 900 light-years closer to us. Administration Contractor,
These facts are true whether little more than 2.5 million Considering that the galaxy
or not our current theories of years to prepare. To figure out itself is 110,000 light-years Quality Assurance, I.M. Systems Group,
the early universe are true. how soon this collision will across (give or take; this num-
Indeed many leading physicists, occur, first we have to figure ber is continually being College Park, Maryland
including some of those revised), this is a small but sig-
nificant mosey. Send us your
The cosmic microwave background, as measured by the Planck satellite, questions
shows tiny temperature fluctuations that were “blown up” when inflation But our assumption isn’t
occurred. These fluctuations are correlated over distances too large for totally correct. As Andromeda Send your astronomy
light to have traveled between them, given the age of the universe, gets closer, the gravitational questions via email to
indicating they were once much closer together. ESA AND THE PLANCK COLLABORATION attraction between it and the [email protected],
Milky Way gets stronger and or write to Ask Astro,
Andromeda accelerates in our P. O. Box 1612, Waukesha,
direction. On top of that, there’s WI 53187. Be sure to tell us
one more factor we don’t know your full name and where
well: Is Andromeda headed you live. Unfortunately, we
cannot answer all questions
submitted.

W W W.ASTR ONOMY.COM 69

READER
GALLERY

1

1. PASS THE BUTTER
The Lobster Claw Nebula (Sharpless
2–157) is relatively easy to image, but
a difficult catch using your eyes and
a telescope. This emission nebula lies
in the constellation Cassiopeia the
Queen. • Peter Jenkins
2. ONCE AND FORMER STAR
CTB 1 (Abell 85) is a supernova
remnant in the constellation
Cassiopeia. It’s about the same
apparent size as the Full Moon but
quite faint. The object is round except
for the breakout structure to the
northeast. George Abell originally
classified it as a planetary nebula,
No. 85 in his catalog.
• Douglas J. Struble

2

70 ASTRONOMY • FEBRUARY 2019

3 3. JUST PASSING THROUGH
45 Comet 21P/Giacobini-Zinner
approaches within 1° of the Salt and
Pepper Cluster (M37) in Auriga on
September 10, 2018. At the time, the
comet shone at 7th magnitude, a bit
fainter than the cluster, which glows
at magnitude 5.6. Comet 21P is the
parent body of the Draconid meteor
shower, a minor display that peaks
October 8 each year. • Miguel Claro

4. SPIRAL SYMMETRY
The delicate arms of NGC 3486 show
the promise of star birth through their
glittering blue and pink patches. This
barred spiral galaxy lies 27.4 million
light-years away in the constellation
Leo Minor. And what a field it floats
in — just look at all the background
galaxies. • Adam Block/Mount
Lemmon SkyCenter/University of
Arizona

5. LOOP THE LOOP
The Cygnus Loop, also known as the
Veil Nebula, is a huge supernova
remnant that measures some 3° across.
Parts of this object have their own
names. Examples include the Witch’s
Broom (NGC 6960), Pickering’s Triangle
(NGC 6979), and the Network Nebula
(NGC 6992/5). • Joseph P. Fisher

6. WHAT’S POLARIS?
This image, taken July 25, 2018, at the
height of the Southern Hemisphere
winter, shows the Amundsen-Scott
South Pole Station in Antarctica. The
station lies at an altitude of 9,301 feet
(2,835 meters) and a latitude within
8.8° of the South Pole. • Hunter Davis

6

W W W.ASTR ONOMY.COM 71

7

7. ROSE-COLORED GASES
The Small Rosette Nebula (Sharpless
2–170) is an emission nebula in the
constellation Cassiopeia the Queen.
It lies some 7,500 light-years away.
The small star cluster centered on the
nebula is Stock 18. • Chuck Ayoub

8. I MEANT TO DO THAT!
The photographer calls this image
“the luckiest shot I ever took.” It
shows the Milky Way, reddish Mars
(bottom), and a superluminous Perseid
meteor. He captured this image with a
13-second exposure August 13, 2018,
at 0h19m33s UT. • Daniel Chamaratos

8

72 ASTRONOMY • FEBRUARY 2019

9

9. SMART-LOOKING OBJECT
The Little Dumbbell (M76) in Perseus
is one of four planetary nebulae in
Charles Messier’s famous catalog of
deep-sky objects that are not comets
— but which looked like comets when
viewed through the small telescopes
of his time. This object appears as a
smaller version of one of the other
planetaries in Messier’s list, the
Dumbbell Nebula (M27). • Jonathan
Talbot

10. SO MANY GALAXIES
The Hercules Cluster of galaxies
(Abell 2151) lies half a billion light-
years away in the boundaries of the
constellation Hercules the Hero. It
contains some 200 members, many
of which are interacting with their
neighbors. • Tony Hallas

Send your images to:

Astronomy Reader Gallery, P. O. Box
1612, Waukesha, WI 53187. Please
include the date and location of the
image and complete photo data:
telescope, camera, filters, and expo-
sures. Submit images by email to

10 [email protected].

W W W.ASTR ONOMY.COM 73

BREAK

THROUGH

A whale of
a show

The universe may be vast,
but it can feel downright
claustrophobic in some
places. Take this region of
western Cetus the Whale,
where two barred spiral
galaxies are locked in a
fatal embrace. Although
these galaxies started to
interact only recently,
signs of chaos appear all
over. The collision has
triggered a burst of star
formation that reveals
itself in a profusion of
bright blue clusters.
Meanwhile, tidal forces
have pulled long streamers
of stars, gas, and dust from
each galaxy. The pair,
collectively cataloged as
Arp 256, lies 350 million
light-years from Earth.

ESA/HUBBLE & NASA

74 ASTRONOMY • FEBRUARY 2019

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SOUTHERN MARTIN GEORGE describes the solar system’s changing landscape
SKY as it appears in Earth’s southern sky.

April 2019: Mercury at its morning best

As darkness falls these early 42"-diameter disk. Also look celestial object except for the Zeta’s west-northwest. Or, per-
autumn evenings, Mars appears for Jupiter’s four bright moons, Sun and Moon. Unfortunately, haps it would be better to say
as a bright point of light low in which change relative positions Venus currently lies far from that NGC 2451 appears to be
the northwest. The Red Planet within just a few hours. Earth and doesn’t look like an open cluster.
stands 3° above the Pleiades star much through a telescope. The
cluster (M45) at the beginning Saturn trails about two planet’s disk spans 12" at mid- There’s no question that the
of April, and the two make a hours behind Jupiter and month and appears nearly full. collection makes a fine target
pretty pair through binoculars appears some 25° to its larger through binoculars. The slight
during the month’s first week. cousin’s lower right in the late Mercury lies several degrees optical aid reveals a group of
evening sky. The magnitude 0.5 below Venus and stands out stars surrounding the magni-
As Mars drifts eastward ringed planet stands out against because no star in the vicinity tude 3.6 sun c Pup. This central
against the starry backdrop, the backdrop of northeastern rivals it. The innermost planet star has a distinct orange-red
however, it leaves the Pleiades Sagittarius the Archer. reaches greatest elongation color that stands out particu-
behind and slides north of the April 11, when it lies 28° west larly well when viewed through
larger Hyades star cluster. The If you thought Jupiter of the Sun and appears nearly a telescope at low power.
V-shaped Hyades spans about looked nice through your tele- 15° high an hour before sunup.
4° and is anchored by the 1st- scope, wait until you get a peek It then shines at magnitude 0.3 Although NGC 2451 makes
magnitude foreground star of Saturn. The best views come just 5° below Venus. (The plan- for great stargazing, it turns out
Aldebaran. Mars remains when it climbs high in the east ets close to within 4° of each not to be a cluster at all. When
within a binocular field of the after midnight because you’re other around midmonth before astronomers studied the precise
cluster for nearly 10 days, pass- looking through less of Earth’s separating again.) The best tele- motions of the stars in this
ing 7° north of similarly col- turbulent atmosphere. On a scopic views of Mercury come direction, they learned that a
ored Aldebaran on the 16th. At night with good conditions, a early in the month when its majority of the bright apparent
magnitude 1.6, the planet glows small scope reveals the planet’s 9"-diameter disk shows a members are merely a chance
slightly fainter than the star. 17"-diameter disk surrounded crescent phase. alignment.
by a dramatic ring system that
Unfortunately, Mars lies far spans 38" and tilts 24° to our The starry sky The story doesn’t end here,
from Earth and offers little to line of sight. You’ll also see however. An open cluster does
those who target it through a Saturn’s biggest and brightest Puppis the Stern rides high in exist in this location, but it is
telescope. The planet shows a moon, 8th-magnitude Titan. the western sky after darkness separate from the object
featureless disk that measures falls in April. The constellation marked NGC 2451 on star
just 4" across. A waning gibbous Moon once belonged to the great ship charts. A close examination
occults Saturn on April 25 for Argo, which French astronomer of the region shows a group
Although Mars is the lone observers in eastern Australia, Nicolas Louis de Lacaille divid- of stars — since named NGC
planet to grace our early eve- New Zealand, and western ed into three parts — Puppis, 2451A — moving together
ning sky, better subjects are South America. From Carina, and Vela — in the 18th through space. This cluster
only a few hours away. Jupiter Auckland, New Zealand, century. Johannes Bayer had lies about 650 light-years
rises around 9 p.m. local time in Saturn’s disk begins to disap- assigned Greek letters to the from Earth.
mid-April and climbs nearly pear behind the Moon’s bright brighter stars in Argo in the
halfway to the zenith in the limb at 12h32m UT with the early 1600s, however. After the As if that weren’t enough, it
east by midnight. At magnitude rings starting to vanish 15 to breakup, the stars in each con- became clear some years later
–2.3, the giant world shines 20 seconds earlier. The ringed stellation retained their original that a second cluster resides in
more than 50 times brighter planet reappears at the dark designations, so each ended up the same direction, at about
than any of the background limb at 13h41m UT. From with only a partial set. twice the distance. Not surpris-
stars in its host constellation, Auckland, the event occurs on ingly, astronomers named it
Ophiuchus the Serpent-bearer. the morning of the 26th. Puppis includes the magni- NGC 2451B.
tude 2.2 star Zeta (ζ) Puppis,
As dazzling as Jupiter The two inner planets an O-type supergiant that Although you won’t be able
appears to the naked eye, take remain companions in the east- ranks among the hottest visible to make out these two struc-
a few moments to observe it ern sky before dawn all month. to the naked eye. But our target tures as you observe the strik-
through a telescope. Even a Venus rises first and appears this month is the nice open star ing collection of suns dubbed
small instrument reveals a far more prominent. At magni- cluster NGC 2451 located 4° to NGC 2451, it’s an appealing
wealth of detail on the planet’s tude –3.9, it outshines every story to keep in mind while
enjoying the view.

STAR S
DOME
PAVO GC 6397
THE ALL-SKY MAP
SHOWS HOW THE Ac_hernar SMC O CTANS
SKY LOOKS AT: NGC 104
9 P.M. April 1 ITARNAGL EU
8 P.M. April 15 HYDRUS M U L
7 P.M. April 30
MUSCA TR
Planets are shown APUS AUS
at midmonth

THIOC RUOL LUOMG E O D A S 2070 NGC O E MAEL A H C `
R _
I LMC MEN N SCP
CIRCINUS
M U

A R O

D

` S
NGC 4755 _
_ RU

CAELUM PICTOR b 3N37G2C R 5139
¡VNOGLCA2C5NA1SR6I
b NTAU

f X U a NGC

CanopuPsU P P I S A N C

g N5G1C28

COLUMBA c VELA a
NGC 2477
ERIDANUS LEPUS ANTLIA
¡ CMAANJIOSR M47 PYXIS C R AT E R
W Rigel ` M41 CORVUS

` _

M42 Sirius

ORION MONO

C

E Alphard _ Path of the Sun

R HYDRA S E X TA N S

O

S

Betelgeuse ` _ Procyon
_
TAU RU S M1 MCI NAONRI S Denebola
_ M65 M66
a

Regulus LEO `

c

M44 a

M35 `
_
GEMINI Pollux CANCER

MAGNITUDES M37 Castor

Sirius Open cluster LEO MINOR

0.0 Globular cluster LYNX

1.0
2.0 Diffuse nebula

3.0 Planetary nebula
4.0
5.0 Galaxy

N

HOW TO USE THIS MAP: This map portrays APRIL 2019
the sky as seen near 30° south latitude.
NORMA Located inside the border are the four Calendar of events 12 First Quarter Moon occurs at
AR directions: north, south, east, and 19h06m UT
west. To find stars, hold the map 1 The Moon is at apogee (405,577
overhead and orient it so a kilometers from Earth), 0h14m UT 16 Mars passes 7° north of
direction label matches the Aldebaran, 22h UT
direction you’re facing. 2 The Moon passes 3° south of
The stars above the Venus, 4h UT The Moon is at perigee
map’s horizon now (364,205 kilometers from Earth),
match what’s Mercury passes 0.4° north of 22h05m UT
in the sky. Neptune, 19h UT
19 Full Moon occurs at 11h12m UT
LUPUS The Moon passes 3° south of
Neptune, 23h UT 22 Uranus is in conjunction with the
C Sun, 23h UT
The Moon passes 4° south of
M83 Mercury, 23h UT 23 Lyrid meteor shower peaks

LIBRA 5 New Moon occurs at 8h50m UT The Moon passes 1.6° north of
Jupiter, 12h UT
_ E Asteroid Iris is at opposition,
Spica 9h UT 25 Pluto is stationary, 9h UT

M104 6 The Moon passes 5° south of The Moon passes 0.4° south of
(ecliptic) Uranus, 13h UT Saturn, 14h UT
VIRGO
8 Dwarf planet Ceres is stationary, The Moon passes 0.07° north of
21h UT Pluto, 20h UT

9 The Moon passes 5° south of 26 Last Quarter Moon occurs at
Mars, 7h UT 22h18m UT

10 Asteroid Pallas is at opposition, 28 The Moon is at apogee
1h UT (404,582 kilometers from Earth),
18h20m UT
Venus passes 0.3° south of
Neptune, 4h UT 30 Saturn is stationary, 2h UT

Jupiter is stationary, 17h UT The Moon passes 3° south of
Neptune, 8h UT
11 Mercury is at greatest western
elongation (28°), 20h UT

S

BOÖTE

Arcturus

_

NGPM64 STAR COLORS:
Stars’ true colors
CANES VENATICI COMA depend on surface
BERENICES temperature. Hot
stars glow blue; slight-
ly cooler ones, white;
intermediate stars (like
the Sun), yellow; followed
by orange and, ultimately, red.
Fainter stars can’t excite our eyes’
color receptors, and so appear white
without optical aid.

Illustrations by Astronomy: Roen Kelly

BEGINNERS: WATCH A VIDEO ABOUT HOW TO READ A STAR CHART AT www.Astronomy.com/starchart.