National Aeronautics and Space Administration

StuStudentReading

about constellations

NASA / AmazingSpaceStudentBackgroundReading:AboutConstellations

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Lookupattheskyonaclearnightandyouwillsee

vastpatternsofbrightstars.Closeyoureyesand

thinkabouttheshapesofthesepatterns.Dotheyremindyou

ofpeople,oranimals,ormythologicalbeingssuchasawinged

horseoragreatwarriorholdinghisswordandshield?

Ancientastronomersimaginedtheysawpeople,animals,

andmythologicalbeingsinthesky.Theycalledthem

constellations.

Constellation Myths

Constellationmythsareancientstoriesaboutthegods,heroes,andmythological

creatures(serpents,dragons,andflyinghorses)featuredintheconstellations.

TheGreeksandRomanscreatedthestoriesfortheconstellationsintheNorthern

Hemisphere,andforafewintheSouthernHemispherethattheycouldsometimes

see,closetothehorizon.

Othersocietieshadtheirownmythologiesforthestars.Thestorieswerepartof

theirreligions,helpingthemtoexplaineverydayevents,suchastheseasons.These

storiesusuallyhaveahero,whowasgivenanhonoraryplaceinthesky,aseithera

rewardoratribute.

MostoftheconstellationsintheSouthernHemispherearemoremodernandwere

identifiedandnamedintheseventeenthcentury,whenEuropeanexplorersfirst

sailedthesouthernseas.Theyarenotusuallyassociatedwithmyths.

Constellations and the Star Patterns They’re Based On

Currently,theentiresky(NorthernandSouthernhemispheres)hasbeendivided

into88regions,eachcontainingaconstellation.Asimple,geometricstarpatternlies

attheheartofeachconstellation.Thestarsinthesepatternsmayappeartobeclose

toeachother,buttheyareoftenveryfarapart.

NASA / AmazingSpaceStudentBackgroundReading:AboutConstellations

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Generally,thereislittleresemblacebetweenthestarpatternandthefully

illustratedobjectorfigurethatrepresentstheconstellation.Forexample,consider

theNorthernHemisphere’swinterconstellation,Orion,theHunter.Thestarpattern

onwhichitisbased—fourbrightstarsatthecornersofatrapezoidandthreestars

inarownearthecenter—doesn’tlookmuchlikeaperson.Theancientsusedalot

ofimaginationwhentheycreatedtheconstellations.

The History of Constellations

ManyofourmodernconstellationscomefromtheancientGreeks,buttheywerenot

thefirstto“see”patternsamongthestars.Historiansspeculatethattheancient

BabyloniansandSumeriansinventedmanyoftheconstellations.Theypassedthe

traditionontotheancientEgyptiansandGreeks.

ArabslearnedoftheGreeks’writingsonastronomyandtranslatedtheminto

Arabic.Greekshadnamedtheirstarsbasedonthestar’spositioninaconstellation,

butArabsbegannamingindividualstarsforpeople.Later,theRomanstranslated

theArabicwritingsintoLatin.WethereforehaveArabicnamesforstarsinGreek

constellationsthatbearLatinnames!

Original Uses for the Constellations

AncientfarmerslivingneartheEquator,wheretheseasonsdon’tvarymuch,

mayhaveusedthestarstotellthemwhentoplantandharvesttheircrops.Since

someconstellationsareonlyvisibleatcertaintimesoftheyear,theirappearance

canrevealwhatmonthitis.Somehistoriansthinktheconstellationmythswere

inventedtohelpthefarmersremembertheconstellations.

Throughouthistory,thestarshavealsobeenusedfor

navigation,eitheracrossadesert,orabodyofwater.

TravelershavehistoricallyreliedontheNorthStar,

Polaris,tomarktheirway.Polarisisthelaststaratthe

NASA / AmazingSpaceStudentBackgroundReading:AboutConstellations

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endofthehandleoftheasterism*oftheLittleDipper,intheconstellationofthe

LittleBear.DuetoEarth’srotation,thestarsappeartomoveacrossthenightsky.

ButPolarisislocatedabovetheaxisonwhichtheEarthrotates,soitdoesn’tchange

positionappreciablywithtime.

Modern Uses for the Constellations

Constellationsgivemodern-dayskywatchersameansofkeepingtrackofthemany

brightstarsinthesky.Bylookingforgroupsofstarsinaparticularpattern,

professionalandamateurastronomerscanlocatespecificstarswithinthegroup.

Forexample,manypeoplecanpickoutthetrapezoidalwinterstarpatternknown

asOrion.Oncetheyhavefound

Orion,theycanfindBetelgeuse(the

starintheupperleft“corner”ofthe

trapezoidformedbythebrightstars)

andRigel(thestarinthelowerright

“corner”ofthesametrapezoid),twoof

thebrighteststarsinthisregionofthe

sky.Constellationsarealsousedto

locateotherobjects,suchasgalaxies

andnebulae(areaswheregasanddust

areclustered).

Constellations and

the World’s Cultures

Manycultureshaveidentifiedstarpatterns,but

rarelydothesepatternscorrespondtothoseof

othercultures.Oneofthepatternsinthenorthern

skythatmanycultureshaverecognizedisthe

asterism*called,intheU.S.,theBigDipper.In

southernFrance,itiscalleda“saucepan”andin

Betelgeuse

Rigel

NASA / AmazingSpaceStudentBackgroundReading:AboutConstellations

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Britain,a“plough.”TheMayanscalleditSevenMacaw,aparrot,buttheHindus

sawsevenwisemen.TheMicmacIndiansofMaritimeCanada,andotherNorth

AmericanIndianssawabear(thepartweseeasthebowlofthedipper),with

hunterstrackingit(thehandle).Therunawayslavescalleditthe“drinkinggourd”

andfolloweditnorthtofreedom.Therefore,theBigDipperbecameasymbolof

freedom.Itisunusualforsomanyculturestopickoutthesamesetofstars.Perhaps

itisbecauseallsevenstarsareverybright.

*Theterm“asterism”isusedheretoindicateasubsetofthestarsinaconstellationthatmakeaseparate,recognizedpatternoftheirown.TheLittleDipperissuchagroupofstars,foundwithintheLittleBear,oneofthe88constellations.ThestarsmakinguptheBigDipperareanother“asterism,”fallingwithintheconstellationoftheGreatBear.