AST 220 Chapter 3 Exam Study Guide 100% Pass

AST 220 Chapter 3 Exam Study
Guide 100% Pass

The simplest reflector telescope design is the prime focus reflector. - ANSWER True

Galileo is credited with designing the first reflector telescope. - ANSWER False

Chromatic aberration affects reflector telescopes. - ANSWER False

All optical telescopes will bring the light from a star to a focus. - ANSWER True

A telescope design that uses a lens and no mirrors is a refractor. - ANSWER True

CCD detectors gather light 0 - 20 times faster than most sensitive photographic film. -
ANSWER True

A Newtonian reflector needs no secondary mirror. - ANSWER False

The Hubble Space Telescope gives us its best resolution with X-rays. - ANSWER False

The Cassegrain reflector needs a primary concave main mirror and a smaller, convex
secondary mirror to reflect light back through a hole in the primary. - ANSWER True

Photography with film is still the preferred way of capturing fine detail in the faintest,
most distant galaxies. - ANSWER False

The light-gathering ability of a telescope is most dependent on the diameter of its
primary objective. - ANSWER True

Mt. Palomar's 200" Gale telescope is the largest reflector now in service. - ANSWER
True

A telescope with and 8-inch mirror will collect twice as much light as one with a 4-inch
mirror. - ANSWER False

The 400" Keck reflector can see objects 100 times fainter than the 40" Yerkes lens. -
ANSWER True

Radio telescopes have poorer angular resolution than optical telescopes because radio
waves a much longer wavelength than optical waves. - ANSWER True

All modern large optical telescopes are refractors. - ANSWER False

Stars do not twinkle; the instability of the atmosphere causes this effect. - ANSWER True

The opacity of the atmosphere is partially corrected via adaptive optics. - ANSWER True

, In the future, adaptive optics will greatly enhance the resolution of the Hubble Space
Telescope. - ANSWER False

Optical telescopes are usually used only at night, but radio telescopes can be used day
or night. - ANSWER True

The Earth's atmosphere is the major factor limiting the use of ground-based radio
telescopes. - ANSWER False

Optical interferometry is more in use than radio interferometry. - ANSWER False

Radio astronomy can only be done from up in space, due to our ionosphere. - ANSWER
False

Like radio and optical astronomy, infrared astronomy is easily done with ground-based
telescopes. - ANSWER False

Due to our ozone layer, ultraviolet astronomy must be done from space. - ANSWER True

The mirrors for X-ray telescopes are same shape as those of optical reflectors. -
ANSWER False

The Compton GRO was the first telescope used for our exploration of high-energy
astronomy. - ANSWER False

Galaxies look the same whether viewed in visible or X-ray wavelengths. - ANSWER False

Which type of telescope has the simplest light path? - ANSWER prime focus reflector

Which of the following is NOT a reason to use a reflecting telescope rather than a
refractor? - ANSWER Lenses are harder to focus than mirrors

What problem do refractor telescopes have that reflectors don't? - ANSWER chromatic
aberration

The most important advantage of CCDs over film is that - ANSWER they record much
more light in a given exposure time.

The primary purpose of a telescope is to - ANSWER collect a large amount of light and
bring it into focus.

A major advantage of Newtonian reflector over a refractor is - ANSWER its compact
size.



Adding a secondary concave lens of carefully chosen different glass to the primary lens
on a refractor allows - ANSWER chromatic aberration to be reduced.