HowtoViewthe2017SolarEclipseSafely
AsolareclipseoccurswhentheMoonblocksanypartoftheSun.OnMonday,August21,2017,asolareclipsewillbe
visible(weatherpermitting)acrossallofNorthAmerica.Thewholecontinentwillexperienceapartialeclipselasting2to
3hours.Halfwaythroughtheevent,anyonewithinaroughly70-mile-widepathfromOregontoSouthCarolina
(http://bit.ly/1xuYxSu)willexperienceabrieftotaleclipse,whentheMooncompletelyblockstheSun’sbrightfaceforup
to2minutes40seconds,turningdayintonightandmakingvisibletheotherwisehiddensolarcorona—theSun’souter
atmosphere—oneofnature’smostawesomesights.Brightstarsandplanetswillbecomevisibleaswell.
LookingdirectlyattheSunisunsafeexceptduringthebrieftotalphaseofasolareclipse(“totality”),whentheMoon
entirelyblockstheSun’sbrightface,whichwillhappenonlywithinthenarrowpathoftotality(http://bit.ly/1xuYxSu).
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TheonlysafewaytolookdirectlyattheuneclipsedorpartiallyeclipsedSunisthrough
special-purposesolarfilters,suchas“eclipseglasses”(exampleshownatleft)orhand-held
solarviewers.Homemadefiltersorordinarysunglasses,evenverydarkones,arenotsafe
forlookingattheSun.Todatefourmanufacturershavecertifiedthattheireclipseglasses
andhand-heldsolarviewersmeettheISO12312-2internationalstandardforsuch
products:RainbowSymphony,AmericanPaperOptics,ThousandOaksOptical,andTSE17.
Alwaysinspectyoursolarfilterbeforeuse;ifscratchedordamaged,discardit.Readandfollowanyinstructions
printedonorpackagedwiththefilter.Alwayssupervisechildrenusingsolarfilters.
StandstillandcoveryoureyeswithyoureclipseglassesorsolarviewerbeforelookingupatthebrightSun.After
glancingattheSun,turnawayandremoveyourfilter—donotremoveitwhilelookingattheSun.
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DonotlookattheuneclipsedorpartiallyeclipsedSunthroughanunfilteredcamera,telescope,binoculars,orother
opticaldevice.Similarly,donotlookattheSunthroughacamera,atelescope,binoculars,oranyotheroptical
devicewhileusingyoureclipseglassesorhand-heldsolarviewer—theconcentratedsolarrayswilldamagethe
filterandenteryoureye(s),causingseriousinjury.Seekexpertadvice
fromanastronomerbeforeusingasolarfilterwithacamera,atelescope,
binoculars,oranyotheropticaldevice.
Ifyouarewithinthepathoftotality(http://bit.ly/1xuYxSu),removeyour
solarfilteronlywhentheMooncompletelycoverstheSun’sbrightface
anditsuddenlygetsquitedark.Experiencetotality,then,assoonasthe
brightSunbeginstoreappear,replaceyoursolarviewertoglanceatthe
remainingpartialphases.
AnalternativemethodforsafeviewingofthepartiallyeclipsedSunispinholeprojection.Forexample,crossthe
outstretched,slightlyopenfingersofonehandovertheoutstretched,slightlyopenfingersoftheother.Withyourback
totheSun,lookatyourhands’shadowontheground.Thelittlespacesbetweenyourfingerswillprojectagridofsmall
imagesontheground,showingtheSunasacrescentduringthepartialphasesoftheeclipse.
Asolareclipseisoneofnature’sgrandestspectacles.Byfollowingthesesimplerules,youcansafelyenjoytheviewand
berewardedwithmemoriestolastalifetime.Moreinformation:
eclipse.aas.orgeclipse2017.nasa.gov
Thisdocumentdoesnotconstitutemedicaladvice.Readerswithquestionsshouldcontactaqualifiedeye-careprofessional.
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