天文学科普知识详说-(26).ppt

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1、光譜儀製作過程及其理論Seeingthispicture,Ithinkthatwemayrotatethegratingsothatthespectrumwillformatthecenter.Finally,wedecidedtorotateittochangetheincidentangleto23deg.Asexpected,thediffractedvisiblelightlocatedatthecenterofthearc.Thisisthedraftofthespectrometer.使用方法Ca

2、ution:Donotlookatthesundirectly天文上的應用Ifyoulookthroughaspectrometer,youmayseesomepatternlikethephotointhepreviouspage,thisiscalledspectrum.Thefirstfirstkindiscalledemissionspectrum,whilethesecondiscalledabsorptionspectrum..ThelastoneisacontinuumspectrumEmiss

3、ionSpectrumAbsorptionSpectrumUsuallyproducedbythingases.e.g.LightbulbLightpassesthroughacold,dilutegas.e.g.SunlightBrightlinesDarklinesEachelementhasitsownuniquespectrumEmission&AbsorptionHereistheemissionspectrumofsomecommonelements.Youmayfindoutallthespec

4、traaredifferent.HydrogenHeliumArgonMercuryThewavelengthofthediffractedlightisindicatedinsidethespectrometer.Since,itiseasilytodeducewhetherwearelookingataemissionspectrumorabsorptionspectrum,withthehelpofthesedata,wemayknowwhatelementsthesourcecontains.光譜與恆

5、星及其他天體Thisisthegraphwhichindicatestheabsorptionspectrumofstarsfromthenew-bornonetothedeadone.Studyingthespectrumofastar,wewillobtainlotsofinformationaboutit,forexample,age,surfacetemperature,distance.Also,wemaygetsomeinformationofcelestialbodiesaroundit.Bla

6、ckHoleisanimportantdiscoverywiththehelpofspectrum.EndCreatedbyWuKaiChiu