Transcript 3. Telescopes: The Tools of Astronomy

Astronomy
A BEGINNER’S GUIDE
TO THE UNIVERSE
EIGHTH EDITION
CHAPTER 3
Telescopes
Clickers
© 2017 Pearson Education, Inc.
Question 1
Modern telescopes use mirrors rather than lenses for all of
these reasons EXCEPT
a) light passing through lenses can be
absorbed or scattered.
b) large lenses can be very heavy.
c) large lenses are more difficult to make.
d) mirrors can be computer controlled to
improve resolution.
e) reflecting telescopes aren’t affected
by the atmosphere as much.
© 2017 Pearson Education, Inc.
Question 1
Modern telescopes use mirrors rather than lenses for all of
these reasons EXCEPT
a) light passing through lenses can be
absorbed or scattered.
b) large lenses can be very heavy.
c) large lenses are more difficult to make.
d) mirrors can be computer controlled to
improve resolution.
e) reflecting telescopes aren’t affected
by the atmosphere as much.
Explanation: Reflecting instruments like the KECK telescope can
be made larger, and more effective, than refractors.
© 2017 Pearson Education, Inc.
Question 2
Seeing in astronomy is a measurement of the
a)
b)
c)
d)
e)
quality of the telescope’s optics.
transparency of a telescope’s lens.
sharpness of vision of your eyes.
image quality due to air stability.
sky’s clarity and absence of clouds.
© 2017 Pearson Education, Inc.
Question 2
Seeing in astronomy is a measurement of the
a)
b)
c)
d)
e)
quality of the telescope’s optics.
transparency of a telescope’s lens.
sharpness of vision of your eyes.
image quality due to air stability.
sky’s clarity and absence of clouds.
Explanation: “Good seeing”
occurs when the atmosphere is
clear and the air is still. Turbulent
air produces “poor seeing, and
fuzzier images.
© 2017 Pearson Education, Inc.
Question 3
Diffraction is the tendency of light to
a)
b)
c)
d)
e)
bend around corners and edges.
separate into its component colors.
bend through a lens.
disperse within a prism.
reflect off a mirror.
© 2017 Pearson Education, Inc.
Question 3
Diffraction is the tendency of light to
a)
b)
c)
d)
e)
bend around corners and edges.
separate into its component colors.
bend through a lens.
disperse within a prism.
reflect off a mirror.
Explanation: Diffraction affects
all telescopes and limits the
sharpness of all images.
© 2017 Pearson Education, Inc.
Question 4
Resolution is improved by using
a) larger telescopes and longer
wavelengths.
b) infrared light.
c) larger telescopes and shorter
wavelengths.
d) lower frequency light.
e) visible light.
© 2017 Pearson Education, Inc.
Question 4
Resolution is improved by using
a) larger telescopes and longer
wavelengths.
b) infrared light.
c) larger telescopes and shorter
wavelengths.
d) lower frequency light.
e) visible light.
Explanation: Diffraction limits
resolution; larger telescopes and
shorter wave light produces
sharper images.
© 2017 Pearson Education, Inc.
Question 5
An advantage of charge-coupled devices (CCDs) over
photographic film is that
a)
b)
c)
d)
e)
they don’t require chemical development.
digital data are easily stored and transmitted.
CCDs are more light sensitive than film.
CCD images can be developed faster.
all of the above are true.
© 2017 Pearson Education, Inc.
Question 5
An advantage of charge-coupled devices (CCDs) over
photographic film is that
a)
b)
c)
d)
e)
they don’t require chemical development.
digital data are easily stored and transmitted.
CCDs are more light sensitive than film.
CCD images can be developed faster.
all of the above are true.
© 2017 Pearson Education, Inc.
Question 6
Radio dishes are large in order to
a)
b)
c)
d)
improve angular resolution.
give greater magnification.
increase the range of waves they can collect.
detect shorter waves than optical telescopes for
superior resolution.
© 2017 Pearson Education, Inc.
Question 6
Radio dishes are large in order to
a)
b)
c)
d)
improve angular resolution.
give greater magnification.
increase the range of waves they can collect.
detect shorter waves than optical telescopes for
superior resolution.
Explanation: Resolution
is worse with long-wave
light, so radio
telescopes must be
large to compensate.
© 2017 Pearson Education, Inc.
Question 7
Adaptive optics refers to
a) making telescopes larger or smaller.
b) reducing atmospheric blurring using computer
control.
c) collecting different kinds of light with one type of
telescope.
d) using multiple linked telescopes.
© 2017 Pearson Education, Inc.
Question 7
Adaptive optics refers to
a) making telescopes larger or smaller.
b) reducing atmospheric blurring using computer
control.
c) collecting different kinds of light with one type of
telescope.
d) using multiple linked telescopes.
Explanation: Shaping a
mirror in real time can
dramatically improve
resolution.
© 2017 Pearson Education, Inc.
Question 8
Radio telescopes are useful because
a)
b)
c)
d)
e)
observations can be made day and night.
we can see objects that don’t emit visible light.
radio waves are not blocked by interstellar dust.
they can be linked to form interferometers.
all of the above are true.
© 2017 Pearson Education, Inc.
Question 8
Radio telescopes are useful because
a)
b)
c)
d)
e)
observations can be made day and night.
we can see objects that don’t emit visible light.
radio waves are not blocked by interstellar dust.
they can be linked to form interferometers.
all of the above are true.
Explanation: The Very Large
Array links separate radio
telescopes to create much
better resolution.
© 2017 Pearson Education, Inc.
Question 9
Infrared telescopes are very useful for observing
a)
b)
c)
d)
e)
pulsars and black holes.
from locations on the ground.
hot stars and intergalactic gas.
neutron stars.
cool stars and star-forming regions.
© 2017 Pearson Education, Inc.
Question 9
Infrared telescopes are very useful for observing
a)
b)
c)
d)
e)
pulsars and black holes.
from locations on the ground.
hot stars and intergalactic gas.
neutron stars.
cool stars and star-forming
regions.
Explanation: Infrared images of star-forming “nurseries” can
reveal objects still shrouded in cocoons of gas and dust.
© 2017 Pearson Education, Inc.
Question 10
The Hubble Space Telescope (HST) offers sharper images
than ground telescopes primarily because
a) HST is closer to planets
and stars.
b) HST uses a larger primary
mirror.
c) it gathers X-ray light.
d) HST orbits above the atmosphere.
e) it stays on the nighttime side of Earth.
© 2017 Pearson Education, Inc.
Question 10
The Hubble Space Telescope (HST) offers sharper images
than ground telescopes primarily because
a) HST is closer to planets
and stars.
b) HST uses a larger primary
mirror.
c) it gathers X-ray light.
d) HST orbits above the atmosphere.
e) it stays on the nighttime side of Earth.
Explanation: HST orbits less than 400 miles above Earth—not
much closer to stars and planets! But it can gather UV, visible,
and infrared light, unaffected by Earth’s atmosphere.
© 2017 Pearson Education, Inc.