Quiz 3
This photo shows a single star photographed by the Hubble Space Telescope. Why doesn't the star appear as a single, sharp point of light?
The wave properties of light make this type of blurring an unavoidable feature of any telescope
The stars in our sky twinkle in brightness and color because of __________.
turbulence in the Earth's atmosphere
The only wavelengths that make it all the way to the surface are_____ and_____ wavelengths, along with small parts of the ____ and ____ spectrum. Most of other wavelengths, including ____ and ____, can be observed only from very high altitudes or space. As a result, without space-based observatories we could not study light from much of the electromagnetic spectrum.
visible light, radio, infrared., ultraviolet, x-ray, gamma ray
What is the angular resolution of the human eye?
about 1 arcminute, or 1/60 of a degree
The Hubble Space Telescope obtains higher-resolution images than most ground-based telescopes because it is:
above Earth's atmosphere
Which technology can allow a single ground-based telescope to achieve images as sharp as those from the Hubble Space Telescope?
adaptive optics
The twin 10-m Keck telescopes can work together to obtain better angular resolution through a technique known as
interferometry
The diffraction limit is a limit on:
A telescope's angular resolution
What do you see orbiting Earth in this photo?
Hubble Space Telescope
What do astronomers mean by light pollution?
Light pollution is light from human sources that makes it difficult to see the stars at night.
This diagram shows the approximate depths to which different wavelengths of light penetrate Earth's atmosphere. Why does it show an airplane?
Much of the infrared spectrum can be observed from an airplane that flies above most clouds
Notice the numbered points on this photo of the Gemini North reflecting telescope. Where is the secondary mirror located?
Point 3
Listed following are distinguishing characteristics and examples of reflecting and refracting telescopes. Match these to the appropriate category.
Reflecting telescopes: Most commonly used by professional astronomers today, The Hubble Space Telescope, worlds largest telescope Refracting telescopes: The worlds largest is 1-meter in diameter, Galileo's telescopes, very large telescopes become "top heavy", incoming light passes through glass
separate the various colors of light, allowing astronomers to determine stellar composition and many other stellar properties.
Spectrographs
Which of the following telescopes benefits most from adaptive optics?
The Keck I telescope on Mauna Kea
The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see?
The photo will seem to show only one star rather than two.
Interferometry uses two or more telescopes to achieve:
an angular resolution equivalent to that of a much larger telescope.
The____of the Hubble Space Telescope is better for shorter (bluer) wavelengths of light than for longer (redder) wavelengths of light.
angular resolution
The Chandra X-ray observatory focuses X rays with ___ mirrors.
grazing incidence
A 10-meter telescope has a larger ___ than a 4-meter telescope.
light-collecting area
Astronomers have begun to build instruments to detect "cosmic messengers" that are not forms of light, such as neutrinos, cosmic rays, and gravitational waves, because they __________.
provide information about distant objects that we cannot obtain from light
What kinds of light are these telescopes designed to detect?
radio waves
The large research observatories on Mauna Kea use giant
reflecting telescopes
Galileo's telescope designs using lenses were examples of
refracting telescope
When your eye forms an image, the _____ plays a role analogous to the detector in a camera.
retina
This photo shows a satellite dish on a house. In essence, the dish is _________.
the primary mirror of a radio telescope