Astronomy QZ06

Currently the largest optical telescope mirrors have a diameter of 5 m 100 m 1 m 10 m

10 m

Whether the telescope's primary optical instrument is reflecting or refracting there is a lens called an eyepiece that does what? Spread the light out for better observing. Bring the light to focus at a particular point. Redirect the light back out to space. Separate the spectrum of light for a particular wavelength.

Bring the light to focus at a particular point.

You are using your friend's telescope to view a comet passing by the Earth. You recognize that you have to look from underneath the primary mirror. This telescope uses what focusing arrangement? Cassegrain focus Newtonian focus Galilean focus prime focus

Cassegrain focus

What is unique about observing radio waves on Earth? The telescopes are easily moveable. It can be done during the day. It is the only part of the electromagnetic spectrum that can enter the atmosphere. The detectors are faster than at other wavelengths.

It can be done during the day.

What do astronomers mean by light pollution? Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations. Light pollution is another name for sunlight which makes it impossible to see stars in the daytime. Light pollution refers to harmful gases emitted by common street lights. Light pollution refers to pollution caused by light industry as opposed to heavy industry.

Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations.

Which of the following statements best describes the two principal advantages of telescopes over eyes? Telescopes have much more magnification and better angular resolution. Telescopes can collect far more light with far greater magnification. Telescopes collect more light and are unaffected by twinkling. Telescopes can collect far more light with far better angular resolution.

Telescopes can collect far more light with far better angular resolution.

Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes? The two stars will appear to be touching and look like a dumbbell. You will see two distinct stars. You will not be able to see these two stars at all. The two stars will look like a single point of light.

The two stars will look like a single point of light.

The primary optical instrument in a refracting telescope is a lens a mirror a spectrum an eyepiece

a lens

The largest visible-light telescopes in the world today use what device as the primary collection of light? a lens a mirror a CCD a spectroscope

a mirror

Which of the following is not a detector of radiation that astronomers have used? a charge-coupled device a photographic plate a piece of photographic film a refracting telescope

a refracting telescope

To break up light into the component colors that it contains astronomers use a device called: a telescope a CCD a spectrometer interferometer array

a spectrometer

The main purpose of using a telescope is to get astronomers closer to the objects they are observing. make the objects in space appear larger so that we can distinguish objects. shift all the electromagnetic radiation from space to the visible region. act as a bucket to collect light.

act as a bucket to collect light.

The size of the device that collects electromagnetic radiation is called a telescope's: aperture magnification focal width resolution

aperture

In a reflecting telescope the primary mirror is located at the top of the telescope tube. at the bottom of the telescope tube. on the side of the telescope. suspended close to the top of the telescope tube.

at the bottom of the telescope tube.

Why would an astro-photographer want to have a good motorized mount to set their telescope upon? because all objects in the sky vary in brightness very quickly because astronomers typically have to look at many object in the sky in a few minutes because the Earth is rotating with the telescope attached to it because the telescope can then be moved out from under the clouds to where it is clear

because the Earth is rotating with the telescope attached to it

What causes stars to twinkle? It is intrinsic to the stars - their brightness varies as they expand and contract. bending of light rays by turbulent layers in the atmosphere variable absorption by interstellar gas along the line of sight to the star variations in the absorption of the atmosphere

bending of light rays by turbulent layers in the atmosphere

A new technique called adaptive optics allows astronomers to: change the region of the electromagnetic spectrum in which their telescope is able to detect radiation change the eyepieces of their telescopes much more quickly than ever before compensate for changes in the Earth's atmosphere and achieve better resolution increase the aperture of their telescopes by connecting several telescopes

compensate for changes in the Earth's atmosphere and achieve better resolution

Detectors operating at this wavelength must be cooled to observe faint astronomical objects. extreme infrared visible X-ray radio

extreme infrared

Order the following in order of increasing efficiency of detecting photons of visible light. eye; photographic film; CCD photographic film; CCD; eye CCD; photographic film; eye CCD; eye; photographic film

eye; photographic film; CCD

Which of these is not an issue in building a refracting telescope? building a large enough housing for the large lens with a long focal length making a very large piece of glass without bubbles or defects chromatic aberration finding an eyepiece that will work with the lens

finding an eyepiece that will work with the lens

At the largest and most modern astronomical observatories on Earth today which of the following regularly happens to the image formed by the telescope? it is recorded on a piece of black and white film which is later developed it is recorded using an electronic detector like a CCD for later analysis it is viewed by a group of graduate students who then make a sketch of it to have a permanent record it is reflected by a special arrangement of mirrors back into the beam and up into the sky

it is recorded using an electronic detector like a CCD for later analysis

In what wavelength range was interferometry first routinely used? optical radio infrared ultraviolet

radio

The largest telescopes in the world collect what region of light from the electromagnetic radiation? radio visible X-ray gamma

radio

The first telescopes and those used by Galileo were: Dobsonians reflectors radio telescopes refractors

refractors

The ability of telescopes to provide precision of detail in an image is known as aberration magnification focusing resolution

resolution

The two regions of the electromagnetic spectrum where the Earth's atmosphere is transparent are visible light and: ultraviolet X-rays gamma rays some radio waves

some radio waves

A knowledgeable amateur astronomer tells you that she has a 14-inch telescope. What does the number 14 refer to? the diameter of the primary lens or mirror the length of the main telescope tube the number of times the image is magnified the focal length

the diameter of the primary lens or mirror

When astronomers design where to build a new and larger telescope which of the following is not an important part of how astronomers select a location? the sky above the place must be dark (little light pollution) the place must be dry (low humidity) the place must have clear weather on as many nights as possible the place must be on a remote island or mountain

the place must be on a remote island or mountain

Which of the following could not be determined by an observation that uses only spectroscopy? the speed at which a distant galaxy is moving away from us the size of a distant galaxy the chemical composition of a distant star the surface temperature of a distant star

the size of a distant galaxy

In order to collect more light astronomers must modify their telescopes. Which of these is not a way to improve observations? put the telescope in orbit around the Earth build more sensitive detectors use a smaller eyepiece build larger optical devices

use a smaller eyepiece

Which of the following types of telescopes can be used ONLY above the Earth's atmosphere? x-ray telescope radio telescope reflector visible-light telescope

x-ray telescope