Can telescopes see through clouds: Cosmos unveiled

Can telescopes see through clouds? It might seem like an absurd question at first glance. Telescopes are fine and sophisticated tools that are developed and maintained by the most brilliant engineering minds in the world. Surely telescopes should be able to see through the clouds. It’s basically just water. Right? Not really. Let’s delve into it.

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Can telescopes see through clouds: short answer

Some of them can, the others can’t. There’s really no other way to answer this question. Nowadays, there are two main types of telescopes – optical telescopes and radio telescopes.

Optical telescopes need a direct and unobscured line of sight. It means that a lot of things, including cloud cover, rain, fog, and other atmospheric disturbances will affect the way a telescope sees the depths of space.

Radio telescopes, on the other hand, do not know these limitations. Unlike optical telescopes, they don’t need clear skies or perfect weather conditions.

They can see through clouds, precipitation, or dust.

So, does that mean that radio telescopes are superior in every respect? Not at all. Furthermore, did you know that two of the most advanced and famous space telescopes, the Hubble telescope and the James Webb telescope, can technically be considered optical telescopes?

As you can see there’s a lot more to the simple question of whether telescopes can see through clouds. So let’s look further into the matter, and find out how different types of telescopes work.

Optical telescope

The first optical telescope was developed by none other than Galileo Galilei in 1607. In its essence, it was a very simple tool, just a long tube with a couple of lenses in it. Very similar to modern-day binoculars and… modern optical telescopes.

Surprisingly, technology has hardly changed over the last four centuries. Most optical telescopes used by amateur astronomers or NASA are just more advanced versions of the first telescope made by Galileo. A system of lenses and mirrors that focalize visible light and make remote objects appear closer.

It means that in a lot of ways, an optical telescope functions similarly to the human eye. Anything that can obscure our vision can stop scientists from observing celestial objects.

As we all know, clouds are made of vapor and tiny water droplets. So even when the light is going through thin clouds it starts bouncing between the water droplets just like between millions of tiny mirrors. As a result, the image of celestial bodies becomes unclear and hazy.

Dust clouds and smog also prevent light from reaching the lenses of a telescope.

So an optical telescope can only be used in perfect weather conditions. Low humidity and little to no cloud cover is ideal. But there are also other variables to be taken into consideration if you want to get sharp images of distant and faint objects in deep space.

Light pollution and night sky

Light pollution is one of the biggest problems. As you might’ve noticed, there are no stars in the sky during the day.

It is because a bright light source like the sun makes it impossible for us to see dim cosmic objects. However, once the sun goes down and the sky becomes dark even the faintest planets receive their opportunity to shine.

Unfortunately, modern cities never sleep. Electricity gave us the ability to turn night into day and this is not great news for astronomers.

In most cities, because of light pollution, you cannot observe celestial bodies. So even when there are clear skies you can pretty much forget about using your telescope from your bedroom.

This is why scientists build their optical telescopes as far from urban areas as possible. For instance, one of the biggest telescopes in the world so far, the Keck Observatory, is built high up on a mountain at a remote location in Hawaii.

Constructing an observatory at high altitudes has other benefits as well. The dense clouds usually form closer to the surface of the Earth.

Moreover, the air itself might also interfere with the observation process.

The light gets distorted when it passes through a portion of hot air. This is why we can hot air waves rising on a hot summer day. This phenomenon can also decrease the quality of images taken by a telescope. This is one of the reasons the scientists decided to launch a telescope, like James Webb into low Earth orbit.

Radio telescopes and radio waves

Radio telescopes function differently. They don’t contain any lenses or mirrors because they don’t need to focalize visible light.

In reality, radio telescopes detect radio waves specifically gamma-rays and x-rays which have longer wavelengths in comparison to visible light. Different radio waves are emitted by all objects in the universe.

These waves can easily pierce through many kinds of matter including water droplets and water vapor. It means that radio telescopes can see through clouds. A radio telescope also doesn’t need a perfectly dark night sky to detect the radio waves just like it doesn’t need perfect weather.

This type of telescope has its disadvantages. First, it is a lot larger than an optical telescope. For example, the largest radio telescope is located in Guizhou province in China and it’s got a diameter of 1640 feet.

Second, since radio telescopes detect radio waves, it’s not sensitive to visible light. It means that you cannot create an image using radio telescopes. You can though get lots of other data about your new discoveries.

You can learn how big they are, where are they located, and if the radiation they emit stays at the same level or changes.

If the radiation emitted by a distant star doesn’t stay at the same level, it might mean that planets are revolving around the star.

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As you can see a certain kind of telescope can see through clouds. Optical telescopes, on the other hand, need a clear sky and good weather. Besides, they cannot see much if the night sky is illuminated by city lights.


Can any telescopes see through clouds?

Yes. Radio telescopes can see through clouds. These telescopes can catch radio waves of various lengths and other types of electromagnetic radiation that are emitted by stars and other celestial bodies.

This radiation can easily pierce through the densest clouds and even firm objects. This property of some electromagnetic waves allows us to use our phones indoors. The signal just goes right through the walls.

Can you see planets through clouds?

Unfortunately not through any. You need a direct and unobscured line of sight to see planets through your optical telescope. Visible light cannot travel through clouds. Moreover, other criteria like illumination level, air pressure, wind speed, and temperature should also be taken into consideration.

Do clouds affect telescopes?

Clouds affect optical telescopes. Radio telescopes, on the other hand, can see through clouds and function in any weather conditions. The rare exceptions are powerful hurricanes or tornados.

Can you see stars with a telescope when it’s cloudy?

As we’ve established, optical telescopes cannot see through clouds.

However, if the light pollution is not too serious and the sky is mostly clear with only thin clouds here and there, you can indeed see stars. Of course, the brighter the star the better it will be visible. The rule of thumb is that if you can see the twinkling with your naked eye you will be able to see the star through the telescope.

Ida Stewart

I have had the incredible opportunity to work as a tour guide at the planetarium for over 5 years. Ever since I was a child, astronomy has held a special place in my heart, and I have nurtured a deep passion for exploring the wonders of the universe. Among all the celestial bodies, Mars has always fascinated me the most, captivating my imagination with its mysterious allure.

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