Studied by 3 people
Which type of focus is most common for larger telescopes?
Cassegrain focus
Why aren't optical or radio telescopes used in particle astronomy, which studies cosmic waves and gravity waves?
Optical and radio telescopes can only detect electromagnetic radiation.
What must be used to maintain the optics and operation of an infrared telescope?
coolant
Space-based telescopes carrying long-wavelength infrared detectors must carry coolant such as liquid helium to chill their optics to near absolute zero temperature.
true
Which form of radiation has the lowest frequency?
microwave
The larger the diameter of a telescope, the more light it will collect.
True
What is the function of the receiver antenna of a radio telescope?
To absorb the radio energy collected by the dish
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?
The mirrors are segmented
What type of electromagnetic radiation does Chandra collect?
X-ray
Light-gathering power and resolving power both depend on what characteristic of a telescope?
diameter
Where would you most likely find a large radio telescope?
in a mountain valley
The Very Large Array radio telescope in New Mexico is an example of the use of which astronomical technique?
interferometry
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.
True
Reflecting telescopes suffer from chromatic aberration because the light must pass through the glass.
false
Which type of electromagnetic wave is the shortest?
gamma
Which telescope will be launched into solar orbit and eventually replace observations made by the Hubble Space Telescope?
JWST
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)?
hexagonal
All telescopes must be operated on site by an astronomer or a technician.
false
n the above image (Figure 6-1), what part of the telescope is represented by the pointer?
achromatic lense
Which part of a telescope is responsible for magnifying an image?
eyepiece
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?
Karen lives in an area with light pollution
Radio telescopes are often located near populated areas.
false
A(n) __________ is both an image-recording device and a photometer.
CCD
What characteristic of a telescope controls the amount of light captured by the telescope?
diameter of the tube
Diffraction, optical quality, and atmospheric conditions all contribute to the limitations of what power of a telescope?
resolving power
What does a refracting telescope use to gather and focus light?
lens
Refracting telescopes use a mirror to gather and focus light.
false
The energy a photon carries is inversely proportional to __________.
its wavelength
Which form of electromagnetic radiation is able to easily reach Earth's surface through an atmospheric window?
radio
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?
25 times
The ____ of a radio telescope collects and focuses radiation.
dish
No radio waves penetrate the Earth's atmosphere.
false
A spectrograph spreads out light according to ____ to form a spectrum.
wavelength
What telescope instrument is used to counter the eastward rotation of Earth?
sidereal drive
gravity waves have never been detected
false
What unit is used to measure wavelengths?
nanometer
Which power of a telescope reveals fine details within an image?
resolving power
CCD images captured from telescopes are often ____ to be stored in a computer's memory for later analysis.
converted to numerical data
Visible light with wavelengths at the long-wavelength end (λ = 700 nm) appears as which color?
red
What technique often requires the use of a laser guide star?
adaptive optics
Resolving power is measured in nanometers.
false
What modern-day instrument do astronomers use to record images from telescopes?
charge-coupled device
What does chromatic aberration separate within refracting telescopes?
color
What is a major selecting factor for astronomers looking to place a telescope atop a mountain?
non-turbulent airflow
Cosmic rays are made of photons.
false
Which is the longest surviving, and most successful, space telescope?
Hubble space telescope
Short-focal-length lenses and mirrors must be strongly curved.
true
Why are X-rays and gamma rays considered dangerous forms of light?
photons of these wavelengths have high energy
Red light of the visible light spectrum has longer wavelengths than blue.
true
Which telescope is the largest refracting telescope in the world?
\n Yerkes Observatory refractor telescope
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Flashcard (21)