CHA[TER 6 ASTRO
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
In a radio telescope, the role that the mirror plays in visible-light telescopes is played by:
a large metal dish (reflector)
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
To break up light into the component colors that it contains, astronomers use a device called:
a spectrometer
Why do telescopes have to have a good motorized drive system to move them quickly and smoothly?
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
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
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
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
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 astronomers do radar astronomy,
they bounce a radar beam off the surface of solid objects in our solar system
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
