Astronomy 9-14-11 Flashcards Table View


What is the primary purpose of an astronomical telescope? To collect a lot of light and bring it to a focus.
The process occurring when photons bounce off a polished surface is called: Reflection.
Which type of telescope has the simplest light path? Prime Focus Reflector.
Which design is subject to chromatic aberration? Refractor.
The tendency of a wave to bend as it passes from one transparent medium to another is called: Refraction.
The primary purpose of a telescope is to Collect a large amount of light and bring it into focus.
What problem do refractor telescopes have that reflectors don't? chromatic aberration
This design involves only one optical surface, a concave mirror. Prime focus Reflector.
The amount of diffraction and thus the resolution of the scope depends upon the wavelength used and the size of the main telescope objective lens or mirror.
The angular resolution of an 8 inch diameter telescope is ____ greater than that of a 2 inch diameter telescope. 4x
It is diffraction that limits the ____ of a telescope's objective. resolution
what is the resolution of a telescope? its ability to distinguish two adjacent objects close together in the sky.
What type of telescope is the Subaru telescope? Cassegrain reflector
what is the resolving power of the telescope? the ability to distinguish adjacent objects in the sky.
The most important advantage of CCDs over film is that they record much more light in a given exposure time.
Refractor telescopes suffer from this separation of light into its component colors. Chromatic Aberration.
The Arecibo radio telescope is laid out like which optical telescope design? Prime Focus Reflector.
What is true of radio telescopes? They have poorer angular resolution than a refractor.
In which part of the electromagnetic spectrum have astronomers been unable to get any information? We now can access information in all spectral lengths.
The amount of diffraction a telescope creates depends upon: The wavelength and the diameter of the telescope objective.
Compared to optical telescopes, radio telescopes are built large because radio photons don't carry much energy.
Why are most large telescopes reflectors, not refractors? All of the above are correct. (Reflectors do not suffer from chromatic aberration like refractors do. Large, very clear lenses are harder to cast than more tolerant mirror blanks, large mirrors need only one optical surface, achromats four surfaces to grind, and large lenses deform under their own weight, but mirrors can be supported.)
Which method of astronomical measurement is the precise measurement of brightness? photometry.
Diffraction is the tendency of light to: spread around corners.
A mountain top is an especially good site for infrared telescopes since: All of the above are factors (You are above most of the carbon dioxide and water vapor int he atmosphere, the cold weather helps the sensitivity of infrared detectors, less air above means better seeing in many cases, there you are closer to celestial objects.)
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