*Large lenses deform under their own weight, but mirrors can be supported
*Large mirrors need only one optical surface, achromats four surface to grind
*Reflectors do not suffer from chromatic aberration like refractors do
*Large, very clear lenses are ha
Why are most large telescopes reflectors, not refractors?
refractor
Which design is subject to chromatic aberration?
chromatic aberration
Refractor telescopes suffer from this separation of light into its component colors
refraction
The tendency of a wave to bend as it passes from one tranparent medium to another is called:
reflection
The process occuring when photons bounce off a polished surface is called:
*They do not have to be developed like film
*The digital data can be easily stored and transmitted
*The CCD is much more light efficient than film
*The CCD image can be monitored for quality as it is being made
A primary advantage of CCDs over photographic film is that:
photometry
Which branch of astronomy is focused on precise measurement of brightness?
spectrometer
The instrument that analyzes the colors and temperatures of stars best is a:
10X
How much better resolution would a 60 mm objective lens have than your eye's 6 mm exit pupil?
bend through a lens
Diffraction is the tendency of light to:
large telescopes have more light grasp and better resolution
What are two advantages of large scopes over smaller ones?
the ability to distinguish adjacent objects in the sky
What is the resolving power of the telescope?
to collect a lot of light and bring it to a focus
What is the primary purpose of an astronomical telescope?
a measurement of the image quality due to air stability
What is "seeing"?
*There you are closer to celestial objects
*You are above most of the carbon dioxide and water vapor in the atmosphere
*The cold weather helps the sensitivity of infrared detectors
*Less air above means beter seeing in many cases
A mountain top is an especially good site for infrared telescopes since:
the effects of atmospheric turbulence
What problem is adaptive optics designed to correct?
to improve the angular resolution of all types of telescopes
For what is an interferometer used?
we now can access information in a spectral lengths
In which part of the EM spectrum have astronomers been unable to get any information??
grazing incidence optics to focus the short wavelengths
The Chandra X-ray telescope must use:
True
T/F: It is much easier to build large reflectors than large refractors
False
T/F: Chromatic aberration affects refractor and reflector telescopes equally
False
T/F: Photography is still the best method for imaging faint galaxies
True
T/F: Spectroscopy uses a prism or diffraction grating to analyze light and determine the composition, temperature, and motion of stars.
True
T/F: Employing active optics greatly enhances the image quality and seeing with optical and infrared telescopes
True
T/F: Telescopes on mountain tops improve seeing by reducing the amount of air above the observer
True
T/F: Radio telescopes have poorer angular resolution than optical telescopes because radio waves have a much longer wavelength than optical waves.
True
T/F: The Very Large Array in New Mexico is a huge radio interferometer
False
T/F: Optical interferometry is easier to do than with radio waves
True
T/F: Chandra is to X-rays what Hubble is to visible light in space observatories.
True
T/F: Chandra and other high energy satellite observatories must use grazing incidence optics to focus these very penetrating photons
mirror
A concave _________ reflects light to a focus
photometer
Accurate measurements of stellar brightness and changes in brightness are made with a:
CCD
Modern telescopes have greatly increased their ability to focus the faintest, most distant galaxies with the use of a _____ for digital imaging
size
The light gathering power of a mirror varies with the ______ of its diameter
Seeing
__________ is a measure of the stability of the atmosphere, usually degraded by tubulent currents in the air.
Adaptive
__________ optics deform the shape of a mirror in phase with changes in the seeing
Infrared
__________ astronomy is difficult from sea level, but more successful if done on mountain tops, above the blocking water vapor.
low, fast
Because radio photons carry ________ energy, radio dishes must be very large.
Interferometry
__________ was a technique first used successfully with long radio waves to combine the signals of two or more reflectors to greatly enhance the resolution of the array.
ozone
Ultraviolet astronomy must be done in space, since the _______ layer blocks these energies from reaching the Earth's surface well.
to determine the origin and evolution of the solar system
What is the goal of comparative planetology?
mass divided by volume
Which of the following defines density?
ecliptic
The plane in which almost all planets orbit the sun is called the:
All have their poles approximately perpendicular to the exliptic
Whcih of these is NOT true of all jovian planets?
Mercury, Venus, Earth, and Mars
Which of the following are terrestrial planets?
Jovian orbits are more eccentric than terrestrials, and farther off the ecliptic
Which of the following is NOT a way that terrestrial and jobian planets differ?
All terrestrials are more dense than any of the jovians
How do the densities of the jovian and terrestrial planets compare?
the Sun
In composition, mass, and density, Jupiter is most like:
pieces of terrestrial planets
In composition and density, the asteroids most resemble:
large and small comets and asteroids, meteoroids, and grains of dust
Which of the following falls into the category of interplanetary debris?
any object smaller than 100 meters in size
The break point between asteroids and meteoroids is:
Their densities are higher than those of asteroids
Which statement about comets is NOT true?
between the orbits of Mars and Jupiter
Most asteroids are found:
changes the speed and direction of a spacecraft nearing a massive planet
A gravitational "sling-shot":
LaPlace's spinning cloud of gas and dust conserving angular momentum
The solar nebula concept of planet formation around the protosun dates back to: