AST 112 - HW 5
Currently the largest optical telescope mirrors have a diameter of
10 m
Suppose astronomers build a 120 m telescope. How much greater would its like collecting area be than that of the 10 m Keck telescope
140
The Hubble space telescope obtains higher-resolution images than most ground based telescopes because it is
Above earth 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 diffraction limit is a limit on
A telescope's angular resolution
What is an artificial star
A point of light in earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations
What causes stars to twinkle
Bending of light rays by turbulent layers in the atmosphere
Telescopes operating at this wavelength must be cooled to observe faint astronomical objects
Extreme infrared
The Hubble space telescope is famous because at least at the time of its launch it was the largest visible light telescope ever built
False
True or false —— a radio telescope and an optical telescope of the same size have the same angular resolution
False
True or false ——professional astronomical telescopes generally have a much greater magnification than the telescopes you can buy in stores
False
True or false: X-ray telescope mirrors are very similar to optical telescope mirrors
False
True or false—— a larger telescope will always have a higher spectral resolution than a smaller telescope when observing at the same wavelength
False
True or false——Improvements in technology will eventually allow the entire electromagnetic spectrum to be observed from high mountaintop observatories
False
How much greater is the light collecting area of one of the 10 m keck telescopes than that of the 5 m Hale telescopes
Four
How much greater is the light collecting area of a 6 m telescope than a 3 m telescope
Four times
What do astronomers mean by light pollution
Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations
What does the technique of interferometry allow
It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes
If you see the color red in an x-ray image from the Chandra x-ray observatory it means
It depends: the colors are chosen arbitrarily to represent something about the x-rays recorded by the telescope
What is meant by spectral resolution
It is a measure of how close two spectral lines can be distinguished
What following statement is not an advantage of the Hubble space telescope over ground-based telescopes
It is closer to the stars
What do we mean by the diffraction limit of a telescope
It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion
If you wanted a radio telescope to achieve the same angular resolution as a visible light telescope it would need to be
Much larger
Why do astronomers need different telescope designs to observe across the electromagnetic spectrum
Photons of different energy have different wavelengths, some of which are not accessible from earth's surface and require different collection strategies
At which wavelength range is there no current or planned space observatory
Radio
In what part of the electromagnetic spectrum do the biggest telescopes on earth operate
Radio
What following studies is best suited to a time monitoring experiment
Studying whether a particular star's brightness is steady or variable
What statement best describes the two principal advantages of telescopes over eyes
Telescopes can collect far more light with far better angular resolution
What is not true about light focusing
The focal plane of a reflecting telescope is always located within a few inches of the primary mirror
What statement could not be measured by an observation that uses only imaging
The rate at which a variable star brightens and dims
What following statement cannot be determined by an observation that uses only spectroscopy
The size of a distant galaxy
Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes
The two stars will look like a single point of light
What following statement is always true about images captured with X-ray telescopes
They are always displayed in false color
What is the purpose of adaptive optics
To eliminate the distorting affects of atmospheric turbulence for telescopes on the ground
True or False——X-rays from astronomical objects can only be detected from telescopes in space
True
True or false ——most astronomical objects emit light over a broad range of wavelengths
True
True or false ——the angular resolution of a telescope is never less than its diffraction limit
True
True or false ——the lens in your eye forms and upside-down image of the world
True
True or false——process of science: if any single test of a scientific hypothesis contradicts it, the hypothesis must be revised
True
What wavelength regions cannot be studied with telescopes on the ground
Ultraviolet and x-rays
