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14 Cards in this Set
- Front
- Back
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As telescopes become larger and larger, astronomers favor ________.
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reflecting telescopes, in part because large lenses and mirrors sag under their own weight, and it is easier to support a mirror along its entire back side than it is to support a lens only around its edge
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Which of the following is NOT a reason to use a reflecting telescope rather than a refractor?
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lenses are harder to focus than mirrors
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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 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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The primary purpose of a telescope is to...
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collect a large amount of light and bring it into focus.
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If we double the diameter of a telescope's mirror, what happens to its light-gathering ability?
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Light-gathering ability quadruples.
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What property of a telescope influences its resolving power?
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The size of the main mirror or lens
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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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The angular resolution of an 8 inch diameter telescope is ________ times greater than that of a 2 inch diameter telescope.
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4
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The amount of diffraction and thus the resolution of the telescope depends upon...
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the wavelength used and the size of the main telescope objective lens or mirror.
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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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Green light has a shorter wavelength than orange light. In a 5 inch telescope, green light will...
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provide better angular resolution than orange light.
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Name two advantages that large telescopes have over small ones...
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I. Larger telescopes collect more light than smaller ones II. The larger telescopes bring the light to a sharper focus |
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