Astronomy Chapter 5 Answers – Flashcards
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reflecting telescopes?
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worlds largest, mostly used by astronomers today and the hubble space telescope
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refracting telescope?
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incoming light passes through glass, largest 1 meter in diameter, top heavy and galileos telescope
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The thickest lenses deflect and bend light?
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the most
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The main reason that most professional research telescopes are reflectors is that?
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large mirrors are easier to build than large lenses
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What is the primary purpose of an astronomical telescope?
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to collect a lot of light and bring it to a focus.
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The process occurring when photons bounce off a polished surface is called:
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reflection
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Which design is subject to chromatic aberration?
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refractor
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The tendency of a wave to bend as it passes from one transparent medium to another is called:
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refraction
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What problem do refractor telescopes have that reflectors don't?
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chromatic aberration
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The amount of diffraction and thus the resolution of the scope depends upon?
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he wavelength used and the size of the main telescope objective lens or mirror
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It is diffraction that limits the ________ of a telescope's objective.
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resolution
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What is the resolution of a telescope?
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its ability to distinguish two adjacent objects close together in the sky
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What is the resolving power of the telescope?
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the ability to distinguish adjacent objects in the sky
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Which method of astronomical measurement is the precise measurement of brightness?
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photometry
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how much better resolution would a 60 mm objective lens have than your eye's 6 mm exit pupil?
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10×
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Diffraction is the tendency of light to:
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spread around corners
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It is diffraction that limits the ________ of a telescope of a given objective diameter.
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resolution
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What are two advantages of large scopes over smaller ones?
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large telescopes have more light grasp and better resolution
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The amount of diffraction a telescope creates depends upon:
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the wavelength and the diameter of the telescope objective
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What type of telescope is the Hubble Space Telescope?
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cassegrain
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The most important advantage of CCDs over film is that?
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they record much more light in a given exposure time
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One advantage of the Hubble Space telescope over ground based ones is that?
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in orbit, it can operate close to its diffraction limit at visible wavelengths
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The primary reason professional observatories are built on the highest mountaintops is to?
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reduce atmospheric blurring
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What is "seeing"?
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a measurement of the image quality due to air stability
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A mountain top is an especially good site for infrared telescopes since:
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All of the above are factors
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What problem does adaptive optics correct?
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turbulence in the earth's atmosphere which creates twinkling
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What is true of radio telescopes?
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they have poorer angular resolution than a refractor
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Which of the following is a problem inherent in all large radio telescopes?
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Radio waves have long wavelengths, so radio telescopes have poor resolution
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Radio dishes are large in order to:
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increase their angular resolution and collect the very weak radio photons
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In astronomy, an interferometer can be used to?
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improve the angular resolution of radio telescopes
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Which of the following greatly improves the angular resolution of radio maps?
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use of interferometers
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The Spitzer Space Telescope (SST) is stationed far from Earth because?
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Earth is a heat source and the telescope must be kept very cool
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In which part of the electromagnetic spectrum have astronomers been unable to get any information?
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We now can access information in all spectral lengths
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Which of the following is currently supplying high resolution x-ray images from space?
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Chandra
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The design of modern x-ray telescopes depends on?
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grazing incidence optics
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The Chandra X-ray telescope must use:
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grazing incidence optics to focus the short wavelengths
