Astronomy 6

Which of the following best describes the principle advantage of CCDs over photographic film?

CCDs capture a much higher percentage of the incoming photons than film.

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light?

Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?

It is closer to the stars.

Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.)

Observatory X can detect dimmer stars and Observatory Y reveals more detail in images.

Which of the following studies is best suited to astronomical observations that fall into the category called timing?

Studying how a star's brightness varies over a period of 3 years.

Which of the following is not a major reason why astronomers would like an observatory on the far side of the Moon?

Telescopes on the Moon could see objects in all parts of the sky equally well, whereas telescopes on Earth can see only portions of the sky that depend on their latitude.

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope?

The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.

Which of the following telescopes would benefit most from adaptive optics?

The Keck I telescope on Mauna Kea.

Suppose you have two small photographs of the Moon. Although both look the same at small size, when you blow them up to poster size one of them still looks sharp while the other one becomes fuzzy (grainy) looking. Which of the following statements is true?

The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy.

The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see?

The photo will seem to show only one star rather than two.

Suppose you point your telescope at a distant object. Which of the following is not an advantage of taking a photograph of the object through the telescope as compared to just looking at the object through the telescope?

The photograph will have far better angular resolution than you can see with your eye.

Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates?

The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

Which of the following best describes the development of astronomical telescopes over the past 60 years?

The world's most powerful telescope remained the same for most of this period, but in the past 20 years many new and more powerful telescopes have been built.

The Chandra X-ray Observatory must operate in space because:

X rays do not penetrate Earth's atmosphere.

The stars in our sky twinkle in brightness and color because of

turbulence in the Earth's atmosphere