Exam 5: The Tools of the Astronomer

The diffraction limit of a 4-m telescope is __________ than that of a 2-m telescope.

Which of the following causes the biggest problem in detecting infrared photons from an astronomical object?

In 2009,the Cassini spacecraft made repeated orbits around Titan,Saturn's largest moon.If this spacecraft orbited at an altitude of 1,000 km above Titan's surface,and its high resolution camera had an angular resolution of 3 arcsec,how large an object could be resolved on Titan's surface?

Radio telescopes are often used in interferometric arrays to increase light gathering power.

What are gravity waves? Have astronomers been able to detect them yet?

Discuss two tools that modern astronomers use to explore the cosmos that are different from traditional optical telescopes,and give an example of how and why each is used.

How faint an object we can see with our eyes is limited only by the integration time of our eye (how often it processes input).

Arrays of radio telescopes can produce much better resolution than single-dish telescopes because they work based on the principle of

The angular resolution of a ground-based telescope (without adaptive optics)is usually

Calculate the resolution of an interferometric array consisting of five 10-m radio telescopes,each located 1,000 meters apart from each other and observing a distant object at a wavelength of 21 cm.

Which telescope would collect 100 times more light than a 1-m telescope?

A beam of light passes from air to water at an incident angle of 40°,relative to a plane perpendicular to the boundary between the two.At what angle will it emerge into the water,relative to a plane perpendicular to the boundary?

The angular resolution of a ground-based telescope is usually set by

According to the law of reflection,if a beam of light strikes a flat mirror at an angle of 30° relative to a plane perpendicular to the surface of the mirror,at what angle will it reflect,relative to a plane perpendicular to the surface of the mirror?

Compare the brightness of the faintest objects you can see with your naked eye,which has an aperture of approximately 1 cm,an integration time of 100 ms,and a quantum efficiency of 10 percent,to the faintest objects you can see in a CCD image taken with a 1-m telescope.Assume the CCD has a quantum efficiency of 80 percent,and the image has an integration time of 10 minutes.

When we determine the angular resolution of an interferometric array of radio telescopes using the formula ,the variable D stands for the

The path of red light is deflected by a larger angle than blue light when passing through a glass prism.

Why do reflecting telescopes usually have a secondary mirror in addition to a primary mirror?

Photography provides an improvement over naked-eye observations because

What is the diffraction limit of a 4-m telescope observing at a wavelength of 650 nm?