Question 1

Currently,the largest optical telescope mirrors have a diameter of

Accepted Answer

A) 1 m. 
B) 2 m. 
C) 5 m. 
D) 10 m. 
E) 100 m. 
A) 1 m. 
B) 2 m. 
C) 5 m. 
D) 10 m. 
E) 100 m.

Question 2

What do we mean by the diffraction limit of a telescope?

Accepted Answer

A) It is the maximum size to which any telescope can be built. 
B) It describes the farthest distance to which the telescope can see. 
C) It describes the maximum exposure time for images captured with the telescope. 
D) It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion. 
A) It is the maximum size to which any telescope can be built. 
B) It describes the farthest distance to which the telescope can see. 
C) It describes the maximum exposure time for images captured with the telescope. 
D) It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.

Question 3

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?

Accepted Answer

A) Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light. 
B) Radio telescopes are designed to collect sound rather than light. 
C) It is because radio telescopes are used in the daytime and visible light telescopes are used at night. 
D) Objects that emit radio waves are always much larger than objects that emit visible light,and therefore require larger telescopes. 
A) Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light. 
B) Radio telescopes are designed to collect sound rather than light. 
C) It is because radio telescopes are used in the daytime and visible light telescopes are used at night. 
D) Objects that emit radio waves are always much larger than objects that emit visible light,and therefore require larger telescopes.

Question 4

What do we mean by the diffraction limit of a telescope?

Accepted Answer

A) It describes the farthest distance to which the telescope can see. 
B) It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images. 
C) It is the maximum size to which any telescope can be built. 
D) It describes the maximum exposure time for images captured with the telescope. 
A) It describes the farthest distance to which the telescope can see. 
B) It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images. 
C) It is the maximum size to which any telescope can be built. 
D) It describes the maximum exposure time for images captured with the telescope.

Question 5

Suppose you want to determine the chemical composition of a distant planet or star.Which of the following will be most useful to have?

Accepted Answer

A) high angular resolution 
B) high turbulence 
C) a radio telescope 
D) high spectral resolution 
A) high angular resolution 
B) high turbulence 
C) a radio telescope 
D) high spectral resolution

Question 6

What is an artificial star?

Accepted Answer

A) a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations 
B) a satellite orbiting Earth 
C) a meteor 
D) a possible source of dark matter in the universe 
E) the unseen member of a binary star system 
A) a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations 
B) a satellite orbiting Earth 
C) a meteor 
D) a possible source of dark matter in the universe 
E) the unseen member of a binary star system

Question 7

X-ray telescope mirrors are very similar to optical telescope mirrors.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope?

Accepted Answer

A) A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light. 
B) A refracting telescope produces refracted images while a reflecting telescope produces reflected images. 
C) Reflecting telescopes make much clearer images than can refracting telescopes of the same size. 
D) It is much easier to make a large refracting telescope than a large reflecting telescope. 
A) A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light. 
B) A refracting telescope produces refracted images while a reflecting telescope produces reflected images. 
C) Reflecting telescopes make much clearer images than can refracting telescopes of the same size. 
D) It is much easier to make a large refracting telescope than a large reflecting telescope.

Question 9

Which of the following is a principal advantage of CCDs over photographic film?

Accepted Answer

A) CCDs allow long exposures (e.g. ,minutes or hours),and film does not. 
B) CCDs can record the colors of astronomical objects accurately,while film cannot. 
C) CCDs capture a much higher percentage of the incoming photons than does film. 
D) Images recorded with CCDs never require any image processing,while images recorded by film often do. 
E) CCDs can be attached to modern telescopes more easily than cameras. 
A) CCDs allow long exposures (e.g. ,minutes or hours),and film does not. 
B) CCDs can record the colors of astronomical objects accurately,while film cannot. 
C) CCDs capture a much higher percentage of the incoming photons than does film. 
D) Images recorded with CCDs never require any image processing,while images recorded by film often do. 
E) CCDs can be attached to modern telescopes more easily than cameras.

Question 10

What is the purpose of adaptive optics?

Accepted Answer

A) It reduces blurring caused by atmospheric turbulence for telescopes on the ground. 
B) It allows several small telescopes to work together like a single larger telescope. 
C) It is a special technology that allows the Hubble Space Telescope to adapt to study many different types of astronomical objects. 
D) It allows ground-based telescopes to observe ultraviolet light that normally does not penetrate the atmosphere. 
A) It reduces blurring caused by atmospheric turbulence for telescopes on the ground. 
B) It allows several small telescopes to work together like a single larger telescope. 
C) It is a special technology that allows the Hubble Space Telescope to adapt to study many different types of astronomical objects. 
D) It allows ground-based telescopes to observe ultraviolet light that normally does not penetrate the atmosphere.

Question 11

The Chandra X-Ray Observatory must operate in space because

Accepted Answer

A) X-rays are too dangerous to be allowed on the ground. 
B) X-rays do not penetrate Earth's atmosphere. 
C) X-ray telescopes require the use of grazing incidence mirrors. 
D) It was built by NASA. 
A) X-rays are too dangerous to be allowed on the ground. 
B) X-rays do not penetrate Earth's atmosphere. 
C) X-ray telescopes require the use of grazing incidence mirrors. 
D) It was built by NASA.

Question 12

Explain what an interferometer is and give an example.

Accepted Answer

Interferometers are groups of telescopes

Question 13

Which of the following wavelength regions can be studied with telescopes on the ground?

Accepted Answer

A) radio,visible,and very limited portions of the infrared and ultraviolet regions 
B) all light with wavelengths longer than ultraviolet wavelengths 
C) all light with wavelengths shorter than infrared wavelengths 
D) infrared,visible,and ultraviolet light 
A) radio,visible,and very limited portions of the infrared and ultraviolet regions 
B) all light with wavelengths longer than ultraviolet wavelengths 
C) all light with wavelengths shorter than infrared wavelengths 
D) infrared,visible,and ultraviolet light

Question 14

The diffraction-limited resolution of a 10-meter telescope is about 0.01 arcsecond for visible light.Would you expect the angular resolution of a 10-meter radio telescope to be better than,equal to,or worse than 0.01 arcsecond? Explain.

Accepted Answer

It would be worse than 0.01 ar

Question 15

What is the purpose of adaptive optics?

Accepted Answer

A) to improve the angular resolution of telescopes in space 
B) to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground 
C) to increase the collecting area of telescopes on the ground 
D) to increase the magnification of telescopes on the ground 
E) to allow several small telescopes to work together like a single larger telescope 
A) to improve the angular resolution of telescopes in space 
B) to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground 
C) to increase the collecting area of telescopes on the ground 
D) to increase the magnification of telescopes on the ground 
E) to allow several small telescopes to work together like a single larger telescope

Question 16

In what wavelength range was interferometry first routinely used?

Accepted Answer

A) radio 
B) infrared 
C) optical 
D) ultraviolet 
E) X-ray 
A) radio 
B) infrared 
C) optical 
D) ultraviolet 
E) X-ray

Question 17

Suppose an astronomer proposed to build a major observatory on the campus of your school.Would it make a good observing site? Explain why or why not.

Accepted Answer

Answers will vary somewhat with location

Question 18

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope?

Accepted Answer

A) The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. 
B) The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope. 
C) The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope. 
D) The answer cannot be determined from the information given in the question. 
A) The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. 
B) The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope. 
C) The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope. 
D) The answer cannot be determined from the information given in the question.

Question 19

Order the following in order of increasing efficiency of detecting photons of visible light.

Accepted Answer

A) eye,photographic film,CCD 
B) photographic film,CCD,eye 
C) CCD,eye,photographic film 
D) CCD,photographic film,eye 
E) eye,CCD,photographic film 
A) eye,photographic film,CCD 
B) photographic film,CCD,eye 
C) CCD,eye,photographic film 
D) CCD,photographic film,eye 
E) eye,CCD,photographic film

Question 20

Which of the following telescopes would benefit most from adaptive optics?

Accepted Answer

A) The Keck I Telescope on Mauna Kea. 
B) The Hubble Space Telescope. 
C) The Arecibo Radio Telescope in Puerto Rico. 
D) The Chandra X-Ray Observatory. 
A) The Keck I Telescope on Mauna Kea. 
B) The Hubble Space Telescope. 
C) The Arecibo Radio Telescope in Puerto Rico. 
D) The Chandra X-Ray Observatory.

Exam 6: Telescopes: Portals of Discovery

Currently,the largest optical telescope mirrors have a diameter of

What do we mean by the diffraction limit of a telescope?

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?

What do we mean by the diffraction limit of a telescope?

Suppose you want to determine the chemical composition of a distant planet or star.Which of the following will be most useful to have?

What is an artificial star?

X-ray telescope mirrors are very similar to optical telescope mirrors.

Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope?

Which of the following is a principal advantage of CCDs over photographic film?

What is the purpose of adaptive optics?

The Chandra X-Ray Observatory must operate in space because

Explain what an interferometer is and give an example.

Which of the following wavelength regions can be studied with telescopes on the ground?

The diffraction-limited resolution of a 10-meter telescope is about 0.01 arcsecond for visible light.Would you expect the angular resolution of a 10-meter radio telescope to be better than,equal to,or worse than 0.01 arcsecond? Explain.

What is the purpose of adaptive optics?

In what wavelength range was interferometry first routinely used?

Suppose an astronomer proposed to build a major observatory on the campus of your school.Would it make a good observing site? Explain why or why not.

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope?

Order the following in order of increasing efficiency of detecting photons of visible light.

Which of the following telescopes would benefit most from adaptive optics?

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light and Matter: Reading Messages from the Cosmos

Our Planetary System

Formation of the Solar System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: The New Science of Distant Worlds

Our Star

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundations of Modern Cosmology

Galaxy Evolution

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Celestial Timekeeping and Navigation

Space and Time

Spacetime and Gravity

Building Blocks of the Universe

Filters