chapter 6

The advantage of an interferometer is that a. the resolution is imrpoved b. the focal length is increased c. the light-gathering power is increased d. diffraction effects are decreased e. chromatic aberration is decreased

a

in practice, the smallest angular size that you can resolve with a 10-inh telescope is governed by the a. blurring caused by earth's atmosphere b. diffraction limit of the telescope c. size of the primary mirror d. magnification of the telescope

a

the light-gathering power of a 4-meter telescope is ______ than that of a 2-meter telescope a. 4x larger b. 8x larger c. 16x larger d. 2x larger

a

the part of the human eye that acts as the detector is the a. retina b. pupil c. lens d. iris

a

high-performance computers have become one of an astronomer's most important tools. which of the following require the use of that type of computer a. analyzing images taken with very large CCDs b. generating and testing theoretical models c. pointing a telescope fro object to object d. studying how astronomical objects or systems evolve

a b d

Rank each of the following colors by how much each refracts, from most (at top) to least (at bottom). a. blue b. green c. red

a, b, c

why are all large astronomical telescopes reflectors a. chromatic aberration is minimized b. they are not as heavy c. they can be shorter d. the glass doesn''t need to be curved

a, b, c

Improved resolution is helpful to astronomers because it enables them to view A. many objects close together. B. very distant objects. C. The motion of objects through space D. small features of an object

a, b, d

All large astronomical telescopes are reflectors because A. chromatic aberration is minimized. B. they are not as heavy. C. they retain better picture quality despite minor accidents. D. they require less maintenance.E.they can be shorter

a, b, e

match the following properties of telescopes with theur cirresponding definitions a. aperture b. resolution c. focal length d. chromatic aberration e. diffraction f. interferometer g. adaptive optics 1. two or more telescopes connected to act as one 2. distance from lens to focal plane 3. diameter 4. ability to distinguish close objects 5. computer-controlled correction for atmospheric distortion 6. color-separating effect 7. smearing effect due to sharp edge

a3b4c2d6e7f1g5

the angular resolution of a ground-based telescope is usually determined by a. diffraction b. the focal length c. refraction d. atmospheric seeing

ad

which of the following can be observed from earth's surface a. radio waves b. gamma radiation c. far uv light d. x-ray light e. visible light

ae

cameras that use adaptive optics provide higher-spatial-resolution images primarily bc a. they operate above earth's atmosphere b. deformable mirrors are used to correct the blurring due to earth's atmosphere c. composite lenses correct for chromatic aberration d. they simulate a much larger telescope the

b

if we could increase the quantum efficiency of the human eye doing so would a. allow humans to see a larger range of wavelengths b. allow humans to see better at night or in other low-light conditions c. increase the resolution of the human eye d. decrease the resolution of the human eye

b

two 10-meter telescopes, separated by 85 meters, can operate as an interferometer. what is its resolution when it observes in the infrared at a wavelength of 2 microns a. 0.01 arcsec b. 0.005 arcsec c. 0.2 arcsec d. 0.05 arcsec

b

why would astronomers put telescopes in airplanes a. to get the telescopes closer to the stars b. to get the telescopes above most of the water vapor in earth's atmosphere c. to be able to observe one object for more than 24 hours w/o stopping d. to allow the telescopes to observe the full spectrum of light

b

rank from easy to detect to difficult a. neutrinos b. infrared photons c. gravity waves

b, a, c

Choose all that apply. CCD cameras are better astronomical detectors than the human eye because A. they can turn photons into protons. B. the integration time can be longer. C. their quantum efficiency is higher. D. they can observe at wavelengths beyond the visible.

b, c, d

CCD cameras have much higher quantum efficiency than that of another detectors. therefore, CCD cameras a. can collect photons for longer times b. can collect photons of different energies c. can generate a signal from fewer photons d. can split light into different colors

c

If one telescope has an aperture of 20 cm, and another has an aperture of 30 cm, and if aperture size is the only difference, then which should you choose, and why? a. the 20 cm bc the light-gathering power will be better b. the 20 cm bc the image size will be longer c. the 30 cm bc the light-gathering power will be better d. the 30 cm bc the image size will be larger

c

refraction is caused by a. light bouncing of f a surface b. light changing colors as it enters a new medium c. light changing speed as it enters a new medium d. two light beams interfering

c

spacecraft are the most effective way to study planets in our solar system because a. planets move too fast across the sky for us to image them well from earth b. planets cannot be imaged from earth c. spacecraft can collect more info than is available just from images from earth d. space missions are easier than long observing campaigns

c

Suppose that a space telescope has been designed that can produce sharp images in visible light. Then a proposal is made to redesign the telescope so that it has a considerably larger focal length but a considerably smaller aperture. Which of the following is an accurate statement of the advantages and/or disadvantages of the new design? A. The telescope will be able to detect dimmer objects, especially using light of longer wavelengths such as red and infrared. But it will be less able to resolve fine detail. B. The telescope will be able to detect dimmer objects, especially using light of shorter wavelengths such as violet and ultraviolet. But it will be less able to resolve fine detail. C. The telescope will be less able to detect dim objects but it will be more able to resolve fine detail, especially when using light of shorter wavelengths such as the ultraviolet. D. The telescope will be more able to detect dim objects, and it will be more able to resolve fine detail regardless of wavelength. E. The telescope will be less able to detect dim objects, and it will be less able to resolve fine detail, especially at longer wavelengths. F. The telescope will be less able to detect dim objects. But it will be more able to resolve fine detail, especially when using light of longer wavelengths such as red and infrared.

d

a grating can spread white light out into a spectrum of colors bc of the property of a. reflection b. interference c. dispersion d. diffraction

d

arrays of radio telescopes can produce much better resolution than single-dish can because they work based on the principle of a. reflection b. refraction c. diffraction d. interference

d

imrpoved resolution is helpful to astronomers bc a. they often want to look in detail ar small features of an object b. they often want to look at very distant objects c. they often want to look at many objects close together d. all of the above

d

which of the following is the biggest disadvantage of putting a telescope in space a. astronomers don't have as much control in choosing what to observe b. astronomoers have to wait until the telescopes come back to earth to get their images c. space telescopes can observe only in certain parts of the electromagnetic spectrum d. space telescopes are much more expensive and riskier than similar ground-based telescopes

d