Why do astronomers continue to build even larger telescopes?

Answer 1

Radio telescopes allow us to see things that can't be seen in visible light. And vice versa, optical telescopes can show things that are not visible in radio telescopes. So, the information from both kinds of telescopes really complements each other.

Answer 2

A larger radio dish can capture more of the signal energy being radiated from a source. Thus the receiver can differentiate signals more accurately and from a greater distance. The comparative amount of energy received between two dishes will be approximately related to their reflective areas.

Answer 3

The size of the dish determines the amount of incoming radiation that can be collected.

Also the radio energy emitted from celestial objects is very weak so it must be strongly amplified before it is recorded and interpreted. The large dish allows the telescope/astronomers to do so.

- Seeds, Michael A.. Horizons: Exploring the Universe. 11 ed. New York: Brooks Cole, 2009. Print.

- "How does a radio telescope work?." Australia Telescope Outreach and Education. CSIRO Australia , 25 July 2008. Web. 16 Feb. 2010. http://outreach.atnf.csiro.au/education/pulseatparkes/radiotelescopeintro.html

Answer 4

The "gain" (light-gathering power, signal-gathering power) of any collector

depends on its size ... measured in wavelengths of the signal it's trying to

collect.

Just for an example . . .

The wavelength of the hydrogen spin transition that's often observed by radio

telescopes (1,420 MHz) is roughly 352 thousand times the wavelength of

yellow light (600 nm) that's often observed by optical telescopes.

And that's why you need a bigger collector for radio waves.

Answer 5

-- The gain ('gathering' power) of a telescope depends on its size, measured in wavelengths

of the radiation it's trying to gather.

-- As an example, the 1420 MHz hydrogen line observed by some radio telescopes

has a wavelength roughly 352,000 times as long as the wavelength in the middle

of visible light.

-- So, in order to have the same gain (gathering power), a radio telescope built to

observe 1420 MHz would need to be 352,000 times as large as a telescope built

to observe visible light.

Answer 6

Radio telescopes allow us to see things that can't be seen in visible light. And vice versa, optical telescopes can show things that are not visible in radio telescopes. So, the information from both kinds of telescopes really complements each other.

Radio telescopes allow us to see things that can't be seen in visible light. And vice versa, optical telescopes can show things that are not visible in radio telescopes. So, the information from both kinds of telescopes really complements each other.

Radio telescopes allow us to see things that can't be seen in visible light. And vice versa, optical telescopes can show things that are not visible in radio telescopes. So, the information from both kinds of telescopes really complements each other.

Radio telescopes allow us to see things that can't be seen in visible light. And vice versa, optical telescopes can show things that are not visible in radio telescopes. So, the information from both kinds of telescopes really complements each other.

Answer 7

The gain of an antennae is related to the size. Basically the larger the antennae and more gain. Radio signals received by radio telescopes are very very low. The dish must be very large as to concentrate the signal onto the receiver so it may be recorded/measured/listened to or what ever else scientists want to do.

Answer 8

-- The gain ('gathering' power) of a telescope depends on its size, measured in wavelengths

of the radiation it's trying to gather.

-- As an example, the 1420 MHz hydrogen line observed by some radio telescopes

has a wavelength roughly 352,000 times as long as the middle wavelength of

visible light.

-- So, in order to have the same gain (gathering power), a radio telescope built to

observe 1420 MHz would need 352,000 times as as much area ... almost 600 times

the diameter ... of a telescope built to observe visible light.

Answer 9

Radiotelescopes are generally far larger than optical telescopes, because the materials don't have to be as dense or as finely built as optical telescopes. Optical telescopes are made of precision-ground mirrors and lenses. Radio telescopes can be made out of wire mesh.

Answer 10

It is based on a ratio of the size of the telescope to the wavelength of the radiation that you are studying and collecting. A radio telescope studies radio waves, which have wavelengths thousands of times longer than visible light, which is collected in an optical telescope. Therefore, a radio telescope must be much larger than an optical telescope.

Fortunately, a radio telescope doesn't have to have complete coverage. So two radio telescopes dozens of miles apart has a resolution much better than a single telescope, or even two radio telescopes close together. This is why there are fields of dozens - soon to be hundreds - of radio telescopes spanning hundreds of miles all observing the same spot. It acts as a radio telescope as big as the farthest separation.

One such is the Very Long Baseline Array radio telescope.