Deck 6: Light and Telescopes

Question 1

Space-based telescopes carrying long-wavelength infrared detectors must carry coolant such as liquid helium to chill their optics to near absolute zero temperature.

Answer 1

True

Question 2

Radio telescopes are often located near populated areas.

Answer 2

False

Question 3

Gravity waves have never been detected.

Answer 3

False

Question 4

Refracting telescopes use a mirror to gather and focus light.

Question 5

Which type of electromagnetic wave is the shortest?

A) radio
B) X-rays
C) visible light
D) gamma
E) microwave

Question 6

What unit is used to measure wavelengths?

A) arc second
B) photons
C) degrees
D) nanometer
E) pixels

Question 7

All telescopes must be operated on site by an astronomer or a technician.

Question 8

The larger the diameter of a telescope, the more light it will collect.

Question 9

What does a refracting telescope use to gather and focus light?

A) eyepiece
B) mirror
C) lens
D) photometer
E) active optics

Question 10

No radio waves penetrate the Earth's atmosphere.

Question 11

Visible light with wavelengths at the long-wavelength end (λ  = 700 nm) appears as which color?

A) red
B) orange
C) yellow
D) green
E) blue

Question 12

Which part of a telescope is responsible for magnifying an image?

A) eyepiece
B) primary lens
C) primary mirror
D) tube diameter
E) photometer

Question 13

Refracting and reflecting telescopes form an image that is small, inverted, and difficult to observe directly; therefore, an eyepiece is normally used to magnify the image and make it convenient to view.

Question 14

Why are X-rays and gamma rays considered dangerous forms of light?

A) These forms of light are only produced by large, dangerous machines.
B) There is no form of protection from these forms of light.
C) These forms of light break through Earth's atmosphere.
D) Photons of these wavelengths have high energy.
E) These forms of light cause sunburn.

Question 15

Which form of electromagnetic radiation is able to easily reach Earth's surface through an atmospheric window?

A) microwave
B) radio
C) X-rays
D) gamma
E) ultraviolet

Question 16

Red light of the visible light spectrum has longer wavelengths than blue.

Question 17

Resolving power is measured in nanometers.

Question 18

Cosmic rays are made of photons.

Question 19

Short-focal-length lenses and mirrors must be strongly curved.

Question 20

Reflecting telescopes suffer from chromatic aberration because the light must pass through the glass.

Question 21

What is so unique about the mirrors of telescopes such as the Keck Observatory, Gran Telescopio Canaries, and the soon-to-be-built Giant Magellan Telescope?

A) The mirrors are made of a newly designed metallic material.
B) The mirrors can fold up went not in use.
C) The mirrors are inexpensive.
D) The mirrors are segmented.
E) The mirrors are thin.

Question 22

Which telescope is the largest refracting telescope in the world?

A) Large Binocular Telescope
B) Gemini-North optical telescope
C) Very Large Array
D) Keck telescope
E) Yerkes Observatory refractor telescope

Question 23

What does chromatic aberration separate within refracting telescopes?

A) color
B) lenses
C) images
D) photons
E) focal points

Question 24

What is the shape of the segmented mirrors of twin Keck Observatory telescopes, Gran Telescopio Canarias, and the James Webb Space Telescope (scheduled to be launched in late 2018) ?

A) spherical
B) hexagonal
C) rectangular
D) triangular
E) octagonal

Question 25

Where would you most likely find a large radio telescope?

A) in a busy, populated area
B) at the peak of a mountain
C) on top of a tall building
D) in a mountain valley
E) near multiple radio towers

Question 26

Jenny, who lives on a farm in a rural part of New York, calls her cousin, Karen, in Brooklyn, to tell her that she can see the Milky Way in tonight's night sky. However, Karen says she can't see it at all.  What is preventing Karen from seeing the Milky Way in the night sky?

A) Karen does not have a strong enough telescope.
B) Karen lives in an area with light pollution.
C) Karen isn't in the same hemisphere as Jenny.
D) Karen needs to use a reflecting telescope.
E) Karen isn't looking in the right direction.

Question 27

If telescope A is 160 cm in diameter, and telescope B is 32 cm in diameter, how much more light does telescope A gather than telescope B?

A) 5 times
B) 10 times
C) 20 times
D) 25 times
E) 100 times

Question 28

What characteristic of a telescope controls the amount of light captured by the telescope?

A) resolving power
B) magnifying power
C) size of eyepiece
D) number of mirrors
E) diameter of tube

Question 29

The ____ of a radio telescope collects and focuses radiation.

A) lens
B) dish
C) mirror
D) antenna
E) computer

Question 30

What is a major selecting factor for astronomers looking to place a telescope atop a mountain?

A) non-turbulent airflow
B) percentage of tree-coverage
C) amount of precipitation
D) the country it is located within
E) the economics of the location

Question 31

Figure 6-1
In the above image (Figure 6-1) , what part of the telescope is represented by the pointer?

A) primary lens
B) primary mirror
C) achromatic lens
D) secondary lens
E) resolving mirror

Question 32

Which telescope will be launched into solar orbit and eventually replace observations made by the Hubble Space Telescope?

A) Hinode
B) Kepler
C) Chandra
D) JWST
E) Fermi

Question 33

What type of electromagnetic radiation does Chandra collect?

A) visible light
B) ultraviolet
C) microwave
D) infrared
E) X-ray

Question 34

Light-gathering power and resolving power both depend on what characteristic of a telescope?

A) number of lenses
B) magnification
C) focal length
D) location
E) diameter

Question 35

Which is the longest surviving, and most successful, space telescope?

A) SOFIA
B) Chandra
C) Kepler Space Observatory
D) Hubble Space Telescope
E) James Webb Space Telescope

Question 36

Diffraction, optical quality, and atmospheric conditions all contribute to the limitations of what power of a telescope?

A) resolving power
B) magnifying power
C) diffraction power
D) light-gathering power
E) focusing power

Question 37

Which type of focus is most common for larger telescopes?

A) Cassegrain focus
B) Galilean focus
C) Newtonian focus
D) Copernican focus
E) Schmidt-Cassegrain focus

Question 38

Which power of a telescope reveals fine details within an image?

A) light-gathering power
B) resolving power
C) magnifying power
D) focusing power
E) defining power

Question 39

What telescope instrument is used to counter the eastward rotation of Earth?

A) Newtonian focus
B) sidereal drive
C) active optics
D) Cassegrain focus
E) floppy mirrors

Question 40

What is the function of the receiver antenna of a radio telescope?

A) To absorb the radio energy collected by the dish
B) To collect and focus the radiation
C) To follow a signal
D) To move the telescope
E) To control the shape of the dish

Question 42

What is a spectrograph and why is it considered an astronomer's most powerful instrument?

Question 43

Which form of radiation has the lowest frequency?

A) gamma
B) microwave
C) ultraviolet
D) infrared
E) visible

Question 44

The energy a photon carries is inversely proportional to __________.

A) its frequency
B) Planck's constant
C) the speed of light
D) its wavelength
E) the gravitational constant

Question 45

Built in 1963, the _______________ telescope in Puerto Rico is the largest single radio dish in the world.

Question 46

Name all the forms of radiation within the electromagnetic spectrum in the order from shortest to longest wavelength.

Question 47

What technique often requires the use of a laser guide star?

A) active optics
B) photometry
C) adaptive optics
D) comparison spectrum
E) representational color imaging

Question 48

Why are reflecting telescopes cheaper to build than refracting telescopes?

Question 49

A lens called the _______________ is typically used to magnify the image and make it convenient to view distant objects.

Question 50

What are the three factors which can limit the resolving power of a telescope?

Question 51

What modern-day instrument do astronomers use to record images from telescopes?

A) photometer
B) grating device
C) spectrograph
D) photographic plate
E) charge-coupled device

Question 52

Why is magnifying power the least important of the three powers of a telescope?

Question 53

A(n) __________ is both an image-recording device and a photometer.

A) interferometer
B) spectrograph
C) CCD
D) primary mirror
E) Newtonian focus

Question 54

The Very Large Array radio telescope in New Mexico is an example of the use of which astronomical technique?

A) spectral analysis
B) photometry
C) interferometry
D) resolving power
E) cosmic analysis

Question 55

CCD images captured from telescopes are often ____ to be stored in a computer's memory for later analysis.

A) pixilated
B) compounded
C) falsely colored
D) divided into smaller images
E) converted to numerical data

Question 56

What must be used to maintain the optics and operation of an infrared telescope?

A) filters
B) lasers
C) coolant
D) oxygen
E) tertiary mirrors

Question 57

A spectrograph spreads out light according to ____ to form a spectrum.

A) wavelength
B) frequency
C) interference
D) aberration
E) grating

Question 58

Large doses of _______________ light can cause sunburn and skin cancers.

Question 59

Why aren't optical or radio telescopes used in particle astronomy, which studies cosmic waves and gravity waves?

A) Cosmic and gravity waves are too dangerous to detect.
B) Particle astronomy can only be studied in deep space.
C) Cosmic and gravity waves are too large of particles for ground-based telescopes.
D) Optical and radio telescopes can only detect electromagnetic radiation.
E) Optical and radio telescopes are not technologically advanced enough to capture these particles.

Question 60

All large astronomical telescopes built since the start of the 20th century have been _______________ telescopes.

Question 61

Astronomers no longer build large observatories in populated areas in order to avoid _______________.

Question 62

It is a common misconception that the purpose of an astronomical telescope is to _______________ images .

Question 63

Why have so many optical telescopes been built atop Mauna Kea, Hawai'i?

Question 64

A optical distortion of refracting telescopes called _______________ causes a separation of colors, such as when you focus on one color, the other colors in an image are blurred.

Question 65

Explain interferometry and provide an example of an observatory that uses this technique.

Question 66

The Chandra observatory uses ________________ mirrors in which the X-rays reflect at shallow angles from the polished inside of the mirrors to form images on X-ray detectors.

Question 67

Two devices that spread white light into a spectrum are __________ and __________.

Question 68

Why do large reflecting telescopes, like the Keck Observatories, have segmented mirrors?

Question 69

One way to measure and compare the strength of the radio signal at various places in the sky is to produce a(n) _______________ in which each color marks areas of similar radio intensity.

Question 70

What are the advantages of putting telescopes in space?  Provide specific examples of three current space telescopes.

Question 71

Explain the difference between cosmic rays and electromagnetic radiation, and how cosmic particles are captured.

Question 72

Space t elescopes carrying long-wavelength infrared detectors must carry _______________ for their optics to avoid the insides of the telescope and instruments from blinding the detectors.

Question 73

Optical telescopes are intended for the study of _______________ light.

Question 74

Light-gathering power is proportional to the _______________ of a telescope's primary lens or mirror.