Hack16.Know Your Constellations


Hack 16. Know Your Constellations

Although stars are important, constellations place those stars in context: constellations are the things you can find in the sky most quickly. And once you've found the constellation that's your point of reference, you can go on to find what you're really looking for.

The first step in learning the night sky is to know the constellations. Before you attempt to identify constellations in the night sky, you should know the names of the constellations you are looking for and how to pronounce those names. There are 88 official constellations. Fortunately, you can learn them in groups because only some of them are visible, according to your latitude and the time of year.

The best way to learn the constellations is to buy a planisphere [Hack #6], which allows you to dial in the date and see an accurate representation of the night sky for that date. Alternatively, the monthly sky charts in Astronomy and Sky & Telescope magazines provide similar whole sky views for the current month.


Table 2-4 lists all 88 modern constellations, including the following data:


Name

The official name of the constellation, as assigned by the International Astronomical Union (IAU), the only body authorized legally to name celestial objects.


Pronunciation

The pronunciations shown are those commonly used by amateur astronomers. Although many are incorrect, these pronunciations are used so commonly that there is little point in attempting to correct them. For example, Orion is correctly pronounced oh-REE-un rather than oh-RYE-un, and Virgo is WIR-goh rather than VUR-goh, but saying oh-REE-un or WIR-goh will draw strange looks from your observing buddies.


Abbr

The official International Astronomical Union (IAU) abbreviation for the constellation name.


Genitive

The Latin genitive case is used to indicate possession of or membership in. In astronomy, the genitive form of the constellation name is used to indicate an object's membership in a constellation. For example, the name sigma Orionis (s-Ori) indicates a star designated sigma that belongs to the constellation Orion [Hack #15].


Dec

The Dec (Declination) of a constellation determines whether you can see all or part of that constellation from your latitude. If you are north of the equator, subtract 90 from your latitude to determine the most southerly object you can observe. For example, our home is at about 36. 2°N latitude. Subtracting 90° from that gives -53.8°, which is the declination of the most southerly object we can see from our home. The star Canopus, alpha Carinae (a-Car), for example, has declination of -52.7°, which means that it never rises more than about 1.1° above our southern horizon.

If you are south of the equator, add 90 to your latitude to determine the most northerly object you can observe. For example, if you are located at 36.2°S latitude (-36.2°), the most northerly object you can observe has a declination of (-36.2° + 90°), or +53.8°. If you are on the equator, at latitude 0°, you can observe any object from declination -90° to +90°, but very northerly and very southerly objects never rise far above your horizon. For example, Polaris (declination +89.25°) never rises higher than 0.75° above your northern horizon.


Season

Constellations are divided by season according to their Right Ascension (RA). A constellation that lies wholly or mostly within the RA range 03: 00 to 09:00 is a Winter constellation; 09:00 to 15:00 is Spring; 15:00 to 21:00 is Summer; and 21:00 to 03:00 is Autumn. The season designation is rather arbitrary, but indicates when the constellation is best placed for viewing during evening hours. For example, Orion, a Winter constellation, can be seen as early as mid Summer, when it rises before dawn, and as late as early Spring, when it sets soon after the Sun.

Table 2-4. The 88 modern constellations

Name

Pronunciation

Abbr

Genitive

Dec (°)

Season

Andromeda

an-DROM-eh-duh

And

Andromedae

+21 to +53

Autumn

Antlia

ANT-lee-uh

Ant

Antliae

-24 to -40

Spring

Apus

A-pus

Aps

Apodis

-67 to -83

Summer

Aquarius

a-KWAIR-ee-us

Aqr

Aquarii

+3 to -24

Autumn

Aquila

AK-will-uh

Aql

Aquilae

+10 to -10

Summer

Ara

AIR-uh

Ara

Arae

-55 to -68

Summer

Aries

AIR-eez

Ari

Arietis

+10 to +30

Autumn

Auriga

uh-RYE-guh

Aur

Aurigae

+28 to +55

Winter

Bootes

bow-OAT-eez

Boo

Bootis

+8 to +55

Spring

Caelum

kye-ELL-um

Cae

Caeli

-27 to -49

Winter

Camelopardalis

CAM-eh-low-PAR-duh-lis

Cam

Camelopardalis

+52 to +87

Winter

Cancer

CAN-sur

Cnc

Cancri

+7 to +33

Winter

Canes Venatici

CAWN-es ven-AT-ih-see

CVn

Canum Venaticorum

+28 to +53

Spring

Canis Major

CAWN-is MAY-jur

CMa

Canis Majoris

-11 to -33

Winter

 

Canis Minor

CAWN-is MYE-nur

CMi

Canis Minoris

0 to +12

Winter

Capricornus

CAP-rih-CORN-us

Cap

Capricorni

-9 to 27

Autumn

Carina

cuh-REE-na

Car

Carinae

-51 to -75

Winter

Cassiopeia

cass-ee-oh-PEE-uh

Cas

Cassiopeiae

+50 to +60

Autumn

Centaurus

sen-TAWR-us

Cen

Centauri

-30 to -65

Spring

Cepheus

SEE-fee-us

Cep

Cephei

+53 to +87

Autumn

Cetus

SEE-tus

Cet

Ceti

+10 to -25

Autumn

Chamaeleon

kuh-MEEL-yun

Cha

Chamaeleontis

-74 to -83

Spring

Circinus

sur-KEE-nus

Cir

Circini

-54 to -70

Spring

Columba

kuh-LUM-ba

Col

Columbae

-27 to -43

Winter

Coma Berenices

KOE-muh BAIR-uh-NEES-us

Com

Comae Berenices

+14 to +34

Spring

Corona Australis

kuh-ROE-nuh aw-STRAWL-is

CrA

Coronae Austri nae

-37 to -45

Summer

Corona Borealis

kuh-ROE-nuh BOR-ee-AL-us

CrB

Coronae Borealis

+26 to +40

Summer

Corvus

KOR-vus

Crv

Corvi

-11 to -25

Spring

Crater

KRATE-ur

Crt

Crateris

-6 to -25

Spring

Crux

KRUX

Cru

Crucis

-56 to -65

Spring

Cygnus

SIG-nus

Cyg

Cygni

+28 to +60

Summer

Delphinus

del-FEE-nus

Del

Delphini

+2 to +21

Summer

Dorado

dor-AW-doe

Dor

Doradus

-49 to -85

Winter

Draco

DRAY-koe

Dra

Draconis

+50 to +80

Summer

Equuleus

eh-KWUH-lee-us

Equ

Equulei

+2 to +13

Autumn

Eridanus

air-uh-DAHN-us

Eri

Eridani

0 to -58

Winter

Fornax

FOR-nacks

For

Fornacis

-24 to -40

Autumn

Gemini

JEM-ih-nye

Gem

Geminorum

+10 to +35

Winter

Grus

GROOSE

Gru

Gruis

-37 to -57

Autumn

Hercules

HUR-cue-leez

Her

Herculis

+4 to +50

Summer

Horologium

hor-oh-LOGE-ee-um

Hor

Horologii

-40 to -67

Winter

Hydra

HYE-druh

Hya

Hydrae

-22 to -65

Spring

Hydrus

HYE-drus

Hyi

Hydri

-58 to -90

Autumn

Indus

IN-dus

Ind

Indi

-45 to -75

Autumn

Lacerta

lay-CERT-uh

Lac

Lacertae

+33 to +57

Autumn

Leo

LEE-oh

Leo

Leonis

-6 to +33

Spring

Leo Minor

LEE-oh MYE-nur

LMi

Leonis Minoris

+23 to +42

Spring

Lepus

LEE-pus

Lep

Leporis

-11 to -27

Winter

Libra

LEE-bruh

Lib

Librae

0 to -30

Summer

Lupus

LOO-pus

Lup

Lupi

-30 to -55

Summer

Lynx

LINKS

Lyn

Lyncis

+34 to +62

Winter

Lyra

LEER-uh

Lyr

Lyrae

+26 to +48

Summer

Mensa

MENS-uh

Men

Mensae

-70 to -85

Winter

Microscopium

mike-roh-SCOPE-ee-um

Mic

Microscopii

-28 to -45

Autumn

Monoceros

MON-oh-SAIR-ose

Mon

Monocerotis

-11 to +12

Winter

Musca

MUSS-kuh

Mus

Muscae

-64 to -74

Spring

Norma

NOR-muh

Nor

Normae

-42 to -60

Summer

Octans

OCT-anz

Oct

Octantis

-75 to -90

Summer

Ophiuchus

oh-FEE-uh-kuss

Oph

Ophiuchi

+14 to -30

Summer

Orion

oh-RYE-un

Ori

Orionis

+8 to +23

Winter

Pavo

PAW-voh

Pav

Pavonis

-57 to -75

Summer

Pegasus

PEG-uh-sus

Peg

Pegasi

+2 to +37

Autumn

Perseus

PERS-ee-us

Per

Persei

+31 to +59

Winter

Phoenix

FEE-nicks

Phe

Phoenicis

-40 to -59

Autumn

Pictor

PIK-tor

Pic

Pictoris

-43 to -64

Winter

Pisces

PYE-seez

Psc

Piscium

-5 to +34

Autumn

Piscis Austrinus

PYE-see z aw-STRINE-us

PsA

Piscis Austrini

-25 to -36

Autumn

Puppis

PUPP-is

Pup

Puppis

-12 to -51

Winter

Pyxis

PICKS-is

Pyx

Pyxidis

-17 to -38

Spring

Reticulum

reh-TICK-you-lum

Ret

Reticuli

-53 to -67

Winter

Sagitta

SADJ-ih-taw

Sge

Sagittae

+17 to +22

Summer

Sagittarius

SADJ-ih-TAIR-ee-us

Sgr

Sagittarii

-12 to -46

Summer

Scorpius

SKOR-pee-us

Sco

Scorpii

-8 to -45

Summer

Sculptor

SKULP-tor

Scl

Sculptoris

-25 to -59

Autumn

Scutum

SKEW-tum

Sct

Scuti

-4 to -16

Summer

Serpens Caput

SUR-penz KAP-put

Ser

Serpentis

-4 to +20

Summer

Serpens Cauda

SUR-penz CAW-duh

Ser

Serpentis

-15 to +6

Summer

Sextans

SEX-tanz

Sex

Sextantis

-11 to +7

Spring

Taurus

TAWR-us

Tau

Tauri

+10 to +30

Winter

Telescopium

tell-uh-SCOPE-ee-um

Tel

Telescopii

-46 to -57

Summer

Triangulum

try-ANG-you-lum

Tri

Trianguli

+26 to +37

Autumn

Triangulum Australe

try-ANG-you-lum aw-STRAWL-eh

TrA

Trianguli Australis

-60 to -70

Summer

Tucana

too-CANN-uh

Tuc

Tucana

-56 to -75

Autumn

Ursa Major

ERS-uh MAY-jur

UMa

Ursae

Majoris

+29 to +73

Spring

Ursa Minor

ERS-uh MYE-nur

UMi

Ursae Minoris

+66 t +90

Summer

Vela

VAY-luh

Vel

Velorum

-40 to -57

Spring

Virgo

VUR-goh

Vir

Virginis

-22 to +15

Spring

Volans

vohl-LANZ

Vol

Volantis

-64 to -75

Winter

Vulpecula

vul-PECK-you-luh

Vul

Vulpeculae

+20 to +30

Summer


If you counted, you may have noticed that there are 89 constellations listed. That's because Serpens, the Snake, is the only non-contiguous constellation, split in two by Ophiuchus, the Snake Bearer. The more northerly portion is called Serpens Caput, or Head of the Snake. The more southerly is Serpens Cauda, or Tail of the Snake. Officially, these two chunks comprise a single constellation. Both use the same abbreviation and genitive, but most astronomers treat them as separate constellations.



    Astronomy Hacks
    Astronomy Hacks: Tips and Tools for Observing the Night Sky
    ISBN: 0596100604
    EAN: 2147483647
    Year: 2005
    Pages: 112

    flylib.com © 2008-2017.
    If you may any questions please contact us: flylib@qtcs.net