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Astronomyl 209/l ASTRl 209l Midterml Examl -l (Latestl 2026/l 2027l Update)l Review|l 100%l Verifiedl Questionsl &l Answersl |l Gradel A
Q:l Whatl isl angularl resolution?
Answer:
Thel abilityl tol seel twol objectsl thatl arel nearlyl inl thel samel direction,l asl separatel objectsl -l thel smallestl angularl distancel betweenl twol objectsl thatl wel canl justl resolve
Q:l Whatl isl thel diffractionl limit?
Answer:
Thel smallestl detailsl youl canl seel withl al telescopel -l itl isl impossiblel tol focusl lightl preciselyl intol al pointl inl thel focall plane
Q:l Howl wouldl thel patternl ofl diffractionl changel inl thel holel al laserl pointerl (redl light)l wasl shiningl throughl wasl madel smaller?l Larger?l Greenl light?
Answer:
Smallerl -l Itl wouldl notl changel inl ringl sizel orl centrall brightl spotl -l thel patternl wouldl justl getl dimmerl becausel lessl lightl getsl throughl thel smallerl hole
Largerl -l patternl wouldl bel blurredl andl eventuallyl disappearl untill onlyl thel familiarl laserl dotl wasl presentl
Greenl -l thel patternl wouldl bel similarl butl smallerl (smallerl wavelength)
Q:l Whatl isl thel centrall spotl ofl al diffractionl called?l Whatl determinesl itsl size? 1 / 3
Answer:
Thel airyl diskl Determinedl byl thel wavelengthl ofl thel lightl &l thel sizel ofl thel aperturel ofl thel telescope
Q:l Howl isl thel diffractionl limitl calculated?
Answer:
diffractionl limitl =l (2.5l xl 10⁵l arcseconds)l xl wavelengthl ofl light/diameterl ofl aperture
*expressl wavelengthl andl diameterl bothl inl meters
Q:l Whatl doesl thel diffractionl limitl determine?l Whatl doesl itl dependl on?
Answer:
Determinesl thel smallestl detaill thatl youl canl seel withl al telescopel
Dependsl onlyl onl thel wavelengthl ofl thel lightl andl thel diameterl ofl thel aperturel ofl thel telescope
Q:l Doesl thel magnificationl ofl thel telescopel contributel tol thel smallestl amountl ofl detaill thel telescopel canl show?
Answer:
NOl -l hasl nothingl tol dol withl itl -l isl onlyl usedl tol seel thel diffractionl patternl madel byl thel aperturel better
Q:l Whatl makesl starsl lookl likel stars?l Whyl dol somel starsl havel biggerl "spikes"?
Answer:
Thel barsl ofl al telescopel causesl thel starsl intl hel skyl tol lookl likel startsl withl "spike" Sizel ofl thel airyl diskl andl thel longerl thel wavelengthl thel largerl thel diffractionl spikes
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Q:l Whatl effectl doesl thel atmospherel havel onl thel visuall ofl stars,l planets,l ect.?
Answer:
Itl absorbsl somel ofl thel lightl (makingl starsl appearl dimmer)l &l reducesl thel detailsl inl thel imagel byl simmeringl effectl (calledl seeing)
Q:l Whatl isl thel twinklingl ofl starsl causedl by?
Answer:
Thel atmospherel -l itl isl relatedl tol seeingl butl itl isl notl thel samel thingl (twinklingl isl calledl scintillation)
Q:l Whatl canl bel usedl tol correctl thel simmeringl ofl thel atmospherel (seeing)?
Answer:
Adaptivel opticsl -l high-techl solutionl Telescopesl inl spacel (abovel thel atmosphere)l -l eg.l Hubblel orl Jamesl Webb
Q:l Howl doesl adaptivel opticsl work?
Answer:
-l Usel al laserl beaml tol createl anl artificiall brightl "star" -l Measurel deformationl ofl artificiall starl byl atmosphere -l Modifyl thel shapel ofl thel mirrorl tol rectifyl thel effectl ofl thel atmosphere -l Dol thisl atl leastl tenl timesl perl second -l Effectivelyl correctsl forl blurringl byl turbulencel inl thel atmosphere
Q:l Whatl isl thel devicel thatl measuresl al spectruml called?
Answer:
Spectrograph
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