Chapter 6

. Your friend, a graduate student in astronomy, is giving you a special tour of the local observatory. You notice that you are viewing the image from the big telescope from underneath the primary mirror; the beam of light has come through a small hole in the main mirror to an eyepiece below. This telescope uses what focusing arrangement?

Cassegrain focus

The first x-ray telescope capable of forming images of x-ray source was called:

Einstein

The first person who regularly turned a telescope to astronomical observations (and published his observations) was:

Galileo Galilei

The first radio telescope was built in the 1930's by

Karl Jansky

The largest refracting telescope in the world, financed by a Chicago millionaire in the 1890's, is at the: a. Lick Observatory b. Yerkes Observatory c. Keck Observatory d. Hale Observatory e. Fraknoi/Morrison/Wolff Observatory

Yerkes Observatory

In a radio telescope, the role that the mirror plays in visible-light telescopes is played by

a large metal dish (antenna)

A graduate student is trying to follow the weather on Jupiter for her PhD thesis. To see the big weather patterns in the upper atmosphere of the planet, she needs to have excellent resolution. What type of telescope would be best for her to use? a. a refractor, with as small an aperture as possible b. a radio telescope c. a large reflector in an observatory located at sea level d. a large reflector located in orbit above the Earth's atmosphere e. you can't fool me, all these telescopes have the same resolution

a large reflector located in orbit above the Earth's atmosphere

The largest visible-light telescopes in the world use what device to collect as much light as possible before the light is brought to a focus (to act as the "light bucket")? a. a lens b. a spectroscope c. a CCD d. a mirror e. a valley in Puerto Rico

a mirror

What type of telescope can be used routinely on the surface of the Earth during the DAY?

a radio telescope

Which of the following is not an advantage that a reflector telescope has over a refractor telescope? a. reflectors can be built with much bigger apertures b. reflectors avoid the problem of chromatic aberration in the lens c. the device that collects the light is more easily supported in a reflector d. a reflector doesn't have to deal with the twinkling of the stars, as a refractor does e. flaws and bubbles in the material inside a thick mirror are not a problem, while flaws and bubbles in the material inside a thick lens are

a reflector doesnt have to deal with the twinkling of stars, as a refractor does

Which of the following is NOT a detector of radiation from space that astronomers have used? a. eyes in the head of the astronomer b. a piece of photographic film c. a photographic plate d. a charge-coupled device (CCD) e. a refracting telescope

a refracting telescope

When an astronomer involved in a research project says he is going to look at the observatory's plate collection, what will he be looking at? a. a collection of souvenir plates, with painting of other observatories from around the world (astronomers collect these as a hobby) b. a series of metal disks used for changing the aperture of reflecting telescopes c. a series of glass plates, with light-sensitive chemicals on them, on which the appearance of the sky was recorded d. a series of insulated plastic shields, which are used to prevent stray infra-red radiation from the observatory from interfering with observations e. what the special-of-the-day is in the observatory cafeteria

a series of glass plates, with light-sensitive chemicals on them, on which the appearances of the sky was recorded

To break up light into the component colors that it contains, astronomers use a device called: a. a telescope b. a CCD c. a spectrometer d. Cassegrain splitter e. interferometer array

a spectrometer

To overcome the problems that blur images and don't provide the best resolution from Earth, astronomers have started using flexible mirrors that change shape many times each second. This technique is called:

adaptive optics

Which of the following has a longer integration time (can collect light for a longer period of time) than the human eye? a. photographic film b. photographic plates c. a CCD (charge coupled device) d. all of the above e. none of the above

all of the above

Why is an image recorded with a CCD better for astronomers than an image recorded on photographic film or plates? a. CCD's are more efficient; more of the light is recorded and not wasted b. CCD's allow more accurate measurements of the brightness of each part of the image c. CCD's have digital output that can go directly to a computer d. all of the above e. none of the above

all of the above

The SOFIA Project is a. a small Lear jet with an 8-inch visible-light telescope on board, designed to search for lost NASA spacecraft b. an x-ray telescope flying many kilometers up (so high that it had to be automated) c. a balloon designed to fly above the ozone layer and search for ultraviolet radiation from space d. an airplane with an infra-red telescope on board designed to fly above much of the water vapor in the Earth's atmosphere e. a NASA aircraft used only by Hollywood movie-makers to teach what it's like in free fall

an airplane with an infrared telescope on board designed to fly above much of the water vapor in the Earth's atmosphere

The size of the device that collects radiation (such as light) is called a telescope's: a. magnification b. resolution c. aperture d. focal width e. Galilean criterion

aperture

Why do telescopes have to have a good motorized drive system to move them quickly and smoothly? a. because the Earth is rotating, with the telescope attached to it b. because astronomers typically have to look at many objects in the sky in a few minutes c. because all objects in the sky vary in brightness very quickly d. because the telescope can then be moved out from under the clouds to where it is clear e. You can't fool me, telescopes never move; they stay in one position all night

because the Earth is rotating, with the telescope attached to it

Why do astronomers prefer to put infrared telescopes on high-flying airplanes or on satellites in space? a. because no infrared radiation can exist anywhere near the Earth's surface b. because the water vapor in the lower atmosphere is very good at absorbing infrared c. because high up the Sun's energy can be used to heat the infrared telescope d. because that way they are significantly closer to the objects they observe e. You can't fool me, all infrared telescopes are located on the Earth's surface

because the water vapor in the lower atmosphere is very good at absorbing infrared

The most important function of an astronomical telescope is to: a. collect as much light as possible and bring it to a focus b. magnify (enlarge) celestial objects so we can see them clearly c. enhance the violet colors of an object, which our eyes have trouble seeing d. bring distant objects closer by pulling on the light e. pierce through the clouds so a cloudy night is not wasted

collect as must light as possible and bring it to a focus

A new technique called adaptive optics allows astronomers to: a. change the eyepieces of their telescopes much more quickly than ever before b. compensate for changes in the Earth's atmosphere and achieve better resolution c. increase the aperture of their telescopes by connecting several telescopes d. change the region of the electro-magnetic spectrum in which their telescope is able to detect radiation e. use the observatory shop to make better eye-glasses for their graduate students

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

The Chandra Observatory orbiting the Earth is designed to a. search for infra-red waves from stars that are in the process of being born b. replace the Hubble Space Telescope, with a much larger mirror for collecting visible light c. search for rapidly changing radio signals d. examine sources of cosmic x-rays e. spy on countries in Asia, such as India, China, and Pakistan

examine sources of cosmic x-rays

You are an astronomer who wants to study a faint star in the process of being born, which gives off most of its faint radiation in the infra-red. Which of the following would NOT be a step you would want to take? a. heat your telescope, so its delicate optics are not cold b. try to have your telescope as high above the layers of water vapor in the Earth's atmosphere as possible c. shield your telescope from the radiation given off by your graduate students d. isolate your telescope in very cold surroundings e. make sure your telescope optics are kept as free of dust as possible

heat your telescope, so its delicate optics are not cold

At the largest and most modern astronomical observatories on Earth today, which of the following regularly happens to the image formed by the telescope? a. it is viewed by a group of graduate students who then make a sketch of it to have a permanent record b. it is recorded on a piece of black & white film, which is then developed in a bath of chemicals c. it is reflected by a special arrangement of mirrors back into the beam and up into the sky d. it is recorded using an electronic detector called a CCD for later analysis e. it is sent to the FBI so they can check for evidence of Russian hacking

it is recored using an electronic detector called a CCD for later analysis

When the James Webb Space Telescope is finally launched, what will be its distinguishing characteristic (what about it will really help astronomers)? a. it will observe gamma-rays from the most energetic events in the universe b. it will be the same size and design as the Hubble Space Telescope, which is wearing out c. it will have the largest mirror ever put into space for observing faint objects d. it will allow us to take pictures with the same resolution as a radio dish e. it will be in low Earth orbit, and thus easy for astronauts to repair

it will have the largest mirror ever put into space for observing faint objects

A very wealthy donor decides to give a large sum of money to your college or university to build the world's largest visible-light gathering telescope. From an astronomical perspective, where would be the best location to put such a telescope? a. in a dark spot right on the campus b. on the west coast of the U.S. very close to sea level (a location like Seattle, for example) c. close to a large city where there are many astronomers to use it d. on a tall, dry mountain peak e. Bayonne, New Jersey

on a tall, dry mountain peak

The earliest telescopes used by astronomers were: a. reflectors b. refractors c. radio telescopes d. about the aperture of the telescope on Mount Palomar e. used late at night to look into the neighbors' windows

refractors

The two regions of the electromagnetic spectrum where the Earth's atmosphere is transparent (radiation can get in) are visible light and: a. ultraviolet b. x-rays c. some radio waves d. gamma-rays e. you can't fool me, the atmosphere is transparent ONLY for visible light

some radio waves

An astronomer who is observing visible light from a glowing cloud of gas in space uses an instrument which contains a grating with thousands of grooves on its surface. What will this instrument allow our astronomer to do? a. take photos with much higher resolution b. spread out the light from the cloud into a spectrum c. observe radio waves from the cloud at the same time as visible light d. turn a reflector into a refractor e. listen to rock and roll music from the 1960's

spread out the light from the cloud into a spectrum

Astronomical observatories have been available since ancient times, and many cultures set aside special sites for astronomical observations. The thing modern observatories have that was missing from these older observatories until about 1610 was: a. a dark site, where lights did not get in the way b. graduate students or other assistants for sharing the astronomer's work c. a method of keeping good records d. a way of measuring from what general direction in the sky a beam of light was coming e. telescopes

telescopes

36. Which of the following is NOT an advantage that the Hubble Space Telescope has over large telescopes on Earth? a. the Hubble is above the Earth's atmosphere, while on the ground star images twinkle and jiggle b. the Hubble can observe at wavelengths (such as UV) which cannot be seen from the ground c. the Hubble has a larger aperture than any visible-light telescope on Earth d. the Hubble has a better resolution than visible-light telescopes on Earth (not counting adaptive optics) e. you can't fool me, all of these are advantages the Hubble has over earth-bound telescopes

the Hubble has a larger aperture than any visible-light telescope on Earth

Which of the following major telescopes was not located in space? a. the Hubble Space Telescope b. the Compton Gamma-ray Observatory c. the International Ultraviolet Explorer d. the Keck Telescope e. the Roentgensatellit (ROSAT) x-ray telescope

the Keck Telescope

Of the following, which has the highest resolution (ability to make out fine detail): a. the German 100-meter radio dish b. the 305-meter Arecibo radio dish in Puerto Rico c. the 64-meter radio dish near Parkes, Australia d. the Very Large Array of radio telescopes in New Mexico e. the Very Long Baseline Array of Radio Telescopes, stretching from the Virgin Islands to Hawaii

the Very Long Baseline Array of Radio Telescopes, stretching from the Virgin Islands to Hawaii

When a knowledgeable amateur astronomer tells you that she has a 14-inch telescope, what does the number 14 refer to?

the diameter or the primary lens or mirror

The U.S. has plans to build a 30-meter telescope, while the Europeans are thinking about 39-meter telescope. What technological innovation allows astronomers to be thinking about telescopes with that large an aperture? a. they can put telescopes on tall mountains now, which we could not ever do before b. they can build much larger lenses for their telescopes with new kinds of plastics c. adaptive optics technology allows them to design a huge mirror which hardly weighs anything d. the mirror in these telescopes will be constructed from many smaller mirrors which will work together e. those big telescopes are just a dream right now; no one can think of a technology for building them.

the mirror in these telescopes will be constructed from many smaller mirrors which will work together

What was the major problem with the Hubble Space Telescope when it was first launched into orbit? a. its antenna wouldn't open, so the data could not be sent back to Earth b. it was in the wrong orbit, so it dipped down into the Earth's thicker atmosphere regularly c. its spectroscope broke during the launch d. the mirror's shape was slightly wrong, so all the light did not come to a single focus e. the mirror cover was stuck in the "partly on" position, making part of the mirror not usable

the mirror's shape was slightly wrong, so all the light did not come to a single focus

When they build big new (visible -light) telescopes, astronomers want to put them in places where they will get the best views of the sky. Which of the following is not an important part of how astronomers select places for new telescopes?" a. the place must have clear weather on as many nights as possible b. the place must be near a university or college c. the sky above the place must be dark (no light pollution) d. the place must be dry (not too much water vapor in the air) e. the air at the place must be quiet, not turbulent

the place must be near a college or university

An astronomer is studying galaxies of stars that are very far away and thus look extremely faint (using visible light). What kind of telescope should she and her graduate students apply for time on? a. a refractor b. the telescope with the biggest aperture possible c. a telescope with a small aperture but with eyepieces that have good magnification d. a telescope built before 1948 e. any telescope will show faint galaxies well; they should just use the one closest to their campus

the telescope with the biggest aperture possible

When astronomers do radar astronomy they

they bounce a radar beam off the surface of solid objects in our solar system

Our textbook discusses that radio astronomers are building more and more arrays of radio telescopes, where many "dishes" are connected together. What advantage do such arrays have? a. they can look through clouds in the Earth's atmosphere, which individual dishes can't do b. they can allow us to split the radio waves into a spectrum, which individual dishes can't c. they provide a higher resolution than individual dishes d. they can be built on flat ground, while individual dishes have to built on very tall mountains e. none of the above

they provide a higher resolution than individual dishes

When the twin Keck telescopes were built in the 1990's, what distinguished them from other very large telescopes of the time? a. they were reflectors, while other large telescopes were all refractors b. they were on a mountain, while all other telescopes had been built near big cities c. they used a mirror assembly that was made of 36 smaller hexagonal mirrors working together d. they had a smaller overall aperture, which made it easier to take pictures e. they had a motorized drive system to allow the telescope to move smoothly

they used a mirror assembly that was made of 36 smaller hexagonal mirrors working together

In the summer of 1996, the European Space Agency announced that it would be suspending the operations of the International Ultraviolet Explorer. Astronomers who were most unhappy about that announcements were likely to be studying what types of objects? a. distant galaxies at the limits of the observable universe b. cool stars just being born from cosmic raw material c. very hot stars d. the Moon e. gamma-ray bursts

very hot stars

Radio telescopes of modest size can't make out as much detail (have a lower resolution) than visible light telescopes. How do astronomers overcome this limitation? a. they have built a radio telescope in the desert that completely covers 1000 square miles b. this problem can't be solved; radio telescopes will always show poor detail c. we can connect several radio telescopes some distance apart together electronically to give us the resolution of a larger telescope d. we have launched a small radio telescope satellite into orbit, which (being above the atmosphere) can make out much more detail than any visible light telescope e. the same engineers responsible for the shape of the mirror for the Hubble Space Telescope are working on this problem; stay tuned

we can connect several radio telescopes some distance apart together electronically to give us the resolution of a larger telescope

Which of the following types of telescopes can be used ONLY above the Earth's atmosphere? a. x-ray telescope b. visible-light telescope c. radio telescope d. reflector e. none of the above

x-ray telescope