Why do radio astronomers place their telescopes in deep valleys?

Why do radio astronomers place their telescopes in deep valleys? &
Why do optical astronomers place their telescopes on top of mountains?

They don’t. Not always. The VLA – the Very Large Array, in New Mexico is on a flat plain. The new Allen array is on a fairly flat plain as well. Radio telescopes aren’t much bothered by atmospheric turbulence. But some frequencies are bothered by water in the air. So, a sub millimeter telescope is being built in the Atacama desert, pretty high up.

Arecibo in Puerto Rico is placed in a deep valley so that the supporting structure doesn’t need to be so big. It’s a cost savings thing, mostly. This is the largest single dish in the world.

Optical astronomers put telescopes on tops of mountains to reduce the amount of air they have to look through. That’s not good enough, so some put their scopes in airplanes (Sofia), balloons (Boomerang), or space (HST, Spitzer, XMM Newton, WMAP, Chandra, Swift, etc.).

Where do i put my scope? Mostly my driveway. It’s not ideal. There’s a street light next to it, and a grocery store with flood lights across the street. The disadvantages are mostly the lights, and noise from cars, and stuff. The advantages are that i can set up in 3 minutes, i don’t need to wait for my eyes to dark adapt, i don’t need a flashlight, and if it’s cold, i can go back inside.


Comments

Why do radio astronomers place their telescopes in deep valleys? — 8 Comments

  1. top of mountains to reduce atmospheric effects. The air is thinner up there.
    Radio telescopes are big, and and valleys help support them, but they are not all in valleys. It doesn’t matter that much
    References :

  2. Just to get the best view possible from the ground on earth. To get away from light pollution or any other things that can distort the image of the universe.
    References :

  3. Optical astronomers need a place where the air is thin, and there is not much atmospheric refraction. Also, they want a place far away from the city lights. Thats why they choose to set up their observatories high in the mountains. The largest observatory is placed in Mount Kea in Hawaii…
    Atmosphere does not affect the radio waves… So radio astronomers dont bother to set up their observatories in such great hights. Instead, they use deep valleys. The radio waves from deep space enter through the atmosphere and bombs straight to the earth’s surface. In case of a deep valley, the radio waves reflect off the valley walls, till they reach the telescope. Radio telescopes are generally placed in arrrays, so that the slightest deflection in the incoming radio waves gets detected.
    References :

  4. Optical telescopes are built as high as practically possible in order to clear as much as we can of the Earth’s atmosphere, which inhibits viewing. I guess by radio telescopes you mean something like Arecibo. The reason that was built right there was the surrounding hills can be used like pylons to help support such a massive structure. As someone else said, probably a majority are built on normal, flat ground, where it is easier to build series of smaller ‘scopes which are then phased together to form a Very Large Array as they are called.
    References :
    I am a professional astronomer and cosmologist.

  5. The actual reason is to reduce wind loading on the structure and possible deflection from the target. Surrounding hills may, just may reduce radio frequency interference from the sides. The answer that the hills collect the signal is not true. Radio telescope antennae are made to be highly directional, the curved surface is no different in principle to a telescope lens. The actual sensing part of the antenna is at the focus. Radio signals are intended to bounce off the metal dish and concentrate at the focus.

    The Parkes radio telescope and the interferometers at Narrabri are not in the middle of a desert, they are in radio-quiet locations.
    References :
    http://en.wikipedia.org/wiki/Parkes_radio_telescope

    http://en.wikipedia.org/wiki/Australia_Telescope_Compact_Array

    http://en.wikipedia.org/wiki/Mopra_Observatory

  6. Optical telescopes are on mountains for better viewing.
    If you’re talking about the Arecibo Radio telescope,
    The valley forms the support of the large reflector.
    It was cheaper to build that way.
    References :

  7. They don’t. Not always. The VLA – the Very Large Array, in New Mexico is on a flat plain. The new Allen array is on a fairly flat plain as well. Radio telescopes aren’t much bothered by atmospheric turbulence. But some frequencies are bothered by water in the air. So, a sub millimeter telescope is being built in the Atacama desert, pretty high up.

    Arecibo in Puerto Rico is placed in a deep valley so that the supporting structure doesn’t need to be so big. It’s a cost savings thing, mostly. This is the largest single dish in the world.

    Optical astronomers put telescopes on tops of mountains to reduce the amount of air they have to look through. That’s not good enough, so some put their scopes in airplanes (Sofia), balloons (Boomerang), or space (HST, Spitzer, XMM Newton, WMAP, Chandra, Swift, etc.).

    Where do i put my scope? Mostly my driveway. It’s not ideal. There’s a street light next to it, and a grocery store with flood lights across the street. The disadvantages are mostly the lights, and noise from cars, and stuff. The advantages are that i can set up in 3 minutes, i don’t need to wait for my eyes to dark adapt, i don’t need a flashlight, and if it’s cold, i can go back inside.

    References :

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