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Astronomy
Test 1 (part 4)
Question | Answer |
---|---|
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 |
What problem do refractor telescopes have that reflectors don't? | chromatic aberration |
A major advantage of a Newtonian reflector over a refractor is: | the elimination of chromatic aberration |
Why are most large telescopes reflectors not refractors? | (all of the above) |
The convex secondary mirror in this design focuses light down through a hole cut in the concave primary mirror. | Cassegrain reflector |
The angular resolution of an 8 inch diameter telescope is ________ greater than that of a 2-inch diameter telescope. | 4 times |
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 (shown below) | Cassegrain reflector |
What type of telescope is the Hubble Space Telescope? | Cassegrain |
The most important advantage of CCDs over film is that: | they record much more light in a given exposure time. |
What problem does adaptive optics correct? | turbulence in the earth's atmosphere which creates twinkling |
The Arecibo radio telescope is laid out like which optical telescope design? | prime focus reflector |
Which of the following is a problem inherent in all large radio telescopes? | Radio waves have long wavelengths, so radio telescopes have poor resolution |
Which of the following greatly improves the angular resolution of radio maps? | use of interferometers |
The design of modern X-ray telescopes depends on: | grazing incidence optics |
It is much easier to build large reflectors than large refractors. | True |
The primary purpose of an astronomical telescope is to magnify the images of distant objects, making them appear closer | False |
The light gathering ability of a telescope is most dependent on the diameter of its primary objective. | True |
One reason for building telescopes on mountain tops is that they improve seeing by reducing the amount of air above the observer. | True |
Optical telescopes are usually used only at night, but radio telescopes can be used day or night. | True |
Radio telescopes have poorer angular resolution than optical telescopes because radio waves have a much longer wavelength than optical waves. | True |
All radio telescopes are reflectors in design. | True |
Optical interferometry is more in use than radio interferometry. | False |
In addition to the visible light, hubble can do some work in the infrarred and ultraviolet portions of the spectrum | True |
Due to our ozone layer, ultraviolet astronomy must be done from space. | True |
Galaxies look the same whether viewed in visible or X-ray wavelengths. | False |