Chapter 6 Astro

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

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

Chandra

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:

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

Which of the following is NOT a detector of radiation from space that astronomers have used?

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 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 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?

all of these choices

Why is an image recorded with a CCD better for astronomers than an image recorded on photographic film or plates?

all of these choices

The SOFIA Project is

an airplane with an infra-red 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:

aperture

Why do telescopes have to have a good motorized drive system to move them smoothly and consistently?

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?

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

The most important function of an astronomical telescope is to:

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

A new technique called adaptive optics allows astronomers to:

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

The Chandra Observatory orbiting the Earth is designed to

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?

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?

it is recorded 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)?

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?

on a tall, dry mountain peak

The earliest telescopes used by astronomers were:

refractors

The two regions of the electromagnetic spectrum where the Earth's atmosphere is transparent (radiation can get in) are visible light and:

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?

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:

telescopes

Which of the following is NOT an advantage that the Hubble Space Telescope has over large telescopes on Earth?

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

Which of the following major telescopes was NOT located in space?

the Keck Telescope

Of the following, which has the highest resolution (ability to make out fine detail):

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 of 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?

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?

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?"

the place must be near a university or college

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?

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?

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?

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?

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?

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?

x-ray telescope