WQ #6

The first radio telescope was built in the 1930's by a. Karl Jansky b. George Ellery Hale c. Edwin Hubble d. a group of Italian astronomers working with Galileo e. Heinrich Hertz

a. Karl Jansky

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

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

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

a. collect as much light as possible and bring it to a focus

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

a. heat your telescope, so its delicate optics are not cold

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

b. spread out the light from the cloud into a spectrum

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

b. the place must be near a university or college

When astronomers do radar astronomy, they a. look for radar beams from civilizations on other planets b. they bounce a radar beam off the surface of solid objects in our solar system c. they send out radar waves that can eventually reach and measure other galaxies d. they send information from one telescope to another on Earth using radar waves e. they try to avoid getting speeding tickets on their way hope from the observatory

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

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? a. prime focus b. Newtonian focus c. Cassegrain focus d. Galilean focus e. out of focus

c. Cassegrain focus

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

c. a series of glass plates, with light-sensitive chemicals on them, on which the appearance 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

c. a spectrometer

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

c. some radio waves

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

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

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

c. they provide a higher resolution than individual dishes.

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

c. 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

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

d. a reflector doesn't have to deal with the twinkling of the stars, as a refractor does

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

d. 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

d. an airplane with an infra-red telescope on board designed to fly above much of the water vapor in the Earth's atmosphere

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

d. examine sources of cosmic x-rays

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

d. on a tall, dry mountain peak

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

d. the Keck Telescope

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

e. telescopes

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

e. 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? a. the number of times the image is magnified (how much bigger it looks) b. the length of the main telescope tube c. the focal length d. the length of the eyepiece tube e. the diameter of the primary lens or mirror

e. the diameter of the primary lens or mirror