astro quiz 6

Which of the following is NOT an advantage that a reflector telescope has over a refractor telescope? the device that collects the light is more easily supported in a reflector a reflector doesn't have to deal with the twinkling of the stars, as a refractor does reflectors avoid the problem of chromatic aberration in the lens reflectors can be built with much bigger apertures 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 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? eyes in the head of the astronomer a charge-coupled device (CCD) a refracting telescope a photographic plate a piece of photographic film

a refracting telescope

In a radio telescope, the role that the mirror plays in visible-light telescopes is played by: an interferometer computer software a large metal dish (antenna) a special kind of lens a spectrometer

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 refractor, with as small an aperture as possible a radio telescope a large reflector in an observatory located at sea level a large reflector located in orbit above the Earth's atmosphere 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 spectroscope a CCD a mirror a valley in Puerto Rico a lens

a mirror

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 peer review focal length adjustment light pollution lowering resolution

adaptive optics

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

all of the above

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

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: magnification aperture Galilean criterion focal width resolution

aperture

Why do telescopes have to have a good motorized drive system to move them quickly and smoothly? because astronomers typically have to look at many objects in the sky in a few minutes because the Earth is rotating, with the telescope attached to it You can't fool me, telescopes never move; they stay in one position all night because all objects in the sky vary in brightness very quickly 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

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

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

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 reflected by a special arrangement of mirrors back into the beam and up into the sky it is recorded using an electronic detector called 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 sent to the FBI so they can check for evidence of Russian hacking it is recorded on a piece of black & white film, which is then developed in a bath of chemicals

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 be the same size and design as the Hubble Space Telescope, which is wearing out it will observe gamma-rays from the most energetic events in the universe it will be in low Earth orbit, and thus easy for astronauts to repair it will allow us to take pictures with the same resolution as a radio dish it will have the largest mirror ever put into space for observing faint objects

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

Which of the following is NOT an advantage that the Hubble Space Telescope has over large telescopes on Earth? the Hubble is above the Earth's atmosphere, while on the ground star images twinkle and jiggle the Hubble can observe at wavelengths (such as UV) which cannot be seen from the ground the Hubble has a larger aperture than any visible-light telescope on Earth the Hubble has a better resolution than visible-light telescopes on Earth (not counting adaptive optics) 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? the Keck Telescope the International Ultraviolet Explorer the Chandra x-ray telescope the Compton Gamma-ray Observatory the Hubble Space Telescope

the Keck Telescope

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 length of the main telescope tube the focal length the length of the eyepiece tube the number of times the image is magnified (how much bigger it looks)

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 those big telescopes are just a dream right now; no one can think of a technology for building them. adaptive optics technology allows them to design a huge mirror which hardly weighs anything they can put telescopes on tall mountains now, which we could not ever do before they can build much larger lenses for their telescopes with new kinds of plastics

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

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 the sky above the place must be dark (no light pollution) the place must be dry (not too much water vapor in the air) the place must have clear weather on as many nights as possible the air at the place must be quiet, not turbulent

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 undergraduate students apply for time on? a refractor any telescope will show faint galaxies well; they should just use the one closest to their campus a telescope with a small aperture but with eyepieces that have good magnification a telescope built before 1948 the telescope with the biggest aperture possible

the telescope with the biggest aperture possible

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? this problem can't be solved; radio telescopes will always show poor detail 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 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 they have built a radio telescope in the desert that completely covers 1000 square miles

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