What is A Telescope Antenna?: The Ins And Outs You Didn’t Know About

Radio astronomy is the task of studying the universe through radio frequency emissions and radio telescopes. But probably, we wouldn’t even know about all the fascinating objects in space today without a radio telescope.

The telescope antenna is the most obvious and essential part of the radio telescope. Without the antenna, it wouldn’t be possible to detect radio electromagnetic signals and convert them into pictures.

But what exactly a telescope antenna is? How does it work? What is the structure of the telescope antenna? In the following discussion, we’ll provide you with all the answers.

Telescope Antenna

Telescope Antenna
Telescope Antenna

The radio telescope was the first success in creating sky pictures through radio waves that were almost impossible to see through the naked eye and visible light. It’s because the electromagnetic spectrum includes more than just visible light.

Radio telescopes are like pretty large satellite dishes. It’s because the wavelengths are quite large, which makes it almost impossible to fit through the antenna aperture. Hence, the telescope is placed somewhere far from the cities to avoid interference in the radio signal.

However, it uses multiple mediums to collect radio waves and create images. An antenna is one of them, which is a system of output recording and reception of sensitive radio waves.

The antenna of the radio telescope works like an objective optical lens for collecting celestial radio signals and transmitting them to the receiver.

Why is Telescope Antenna Important?

Radio telescopes are the primary machine to study radio frequency waves from extraterrestrial sources by radio astronomers. The radio telescope uses an antenna system to receive high celestial radio waves and transfer them to the receiver.

A telescope antenna is necessary for a radio telescope as it works like an optical objective lens to transmit signals to the receiver. Then like a photographic plate, the receiver amplifies, perceives, and records the waves.

If the receiver can’t detect any frequencies or fine details, astronomers cannot see any image on the computer. Therefore, an antenna is equally important for a radio telescope, just like the other parts.

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Types Of Telescope Antenna

Generally, two types of telescope antennas are popular among astronomers: pencil-beam antenna and reflector antenna. Here are the details about these antennas:

  • Pencil-Beam Antenna

This type of telescope antenna pattern contains the main lobe or a single output terminal pair. It can also come with multiple main lobes for individual output. 

A single pair of terminals communicate with the main lobe for the sense of output polarization, such as elliptical, linear, or circular.

  • Reflector Antenna

The most common type of telescope antenna is a reflector antenna. This type of telescope antenna includes single or multiple reflecting surfaces and feed systems to reflect electromagnetic waves.

A reflector antenna offers versatility, high radiation performance, and readiness, for which it’s only used in satellite, deep-space telemetry, radars, radio astronomy, and remote sensing.

The main benefit of a reflector antenna is that the receiver can easily correspond to it. Hence, the antenna system can finish the aperture synthesis of a specific area of the sky in less time than a typical two-element telescope.

Structure Of Telescope Antenna

Depending on the antenna gain and antenna resolution, the telescope antenna structure design may vary. The antenna is perched in the middle of the dish or primary parabolic reflector surface. The collected distance celestial radio source reflects on the dish, then focuses it toward the antenna telescope.

Depending on the desired resolving power, the antennas can be quite large. However, the larger the antenna, the better the focus on gathering energy from a small region of ​​the celestial sphere. Therefore, the sky, where the antenna is most sensitive, is considered the antenna’s beam pattern.

Radiation/Frequency Of Telescope Antenna

The primary astronomical machine is a radio telescope with a wave receiver and antenna system. It collects distance radio-frequency radiation from galaxies and stars. The wavelength of radiation or frequency is between 10 meters (30 MHz) and 1 millimeter (300 GHz).

How Does Telescope Antenna Work?

The primary task of the radio telescope antenna is transmitting radio electromagnetic waves to the feed horn or dipole. 

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Plus, the antenna resembles the optical telescope lens. It collects the minute amount of frequency energy and then alters it into a tiny electrical current to measure.

Generally, radio waves contain weak electrical currents. The dish collects incoming radio waves from space and reflects them on the surface. Due to the clever radio engineering design, the reflected waves always focused on the antenna.

After that, the antenna directs radio waves to the feed horn. It processes the waves and sends them to the amplifier through a cable. Then amplifying device inspects the electromagnetic wave and transmits it to the computer.

How Does Telescope Antenna Work?

Advantages Of Telescope Antenna

Here are some of the benefits of using a radio telescope antenna:

  • Operates Continuously

An antenna can work continuously every day and night in any weather condition, no matter sunny or stormy. This way, astronomers can continue their research without any interruption.

  • Always Trace Waves

Electromagnetic waves are indifferent to clouds. An antenna can still trace waves from space through clouds effortlessly. However, strong winds and thunderstorms may interfere with the dish function.

  • Unbothered To Space Particles

An antenna can draw radio signals even with the presence of celestial dust or particles without being reflected.

Disadvantages Of Telescope Antenna

Just like a telescope antenna has some advantages, it includes some disadvantages too. Here are they:

  • High-Quality Antenna For Strong Signal

A higher gain antenna is required to receive the strongest signal and highest connection.

  • Requires Vast Area

A vast area is needed to draw waves from space without interference as the wavelengths are long but weak.

Applications Of Telescope Antenna: Where to Implement?

An antenna is used to receive and send radio transmissions simultaneously. Multiple technologies like Wi-Fi, television, cars, phones, radars, GPS, space communication, etc., use an antenna for transmitting waves.

A telescope antenna is used by scientists to study planets, stars, moons, and galaxies and map the distance of space. Astronomers can also calculate the frequencies if any source is moving from the signal antenna receives.

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For example, the famous James Webb Space Telescope also uses a high gain telescope antenna to transmit radio electromagnetic wave from which astronomers has discovered many unknown odds since 2019.


Do stars emit radio waves?

Yes, stars emit radio waves. But compared to other celestial objects, the waves of stars are relatively weak in the sky.

What waves are used in telescopes?

Radio telescope uses radio waves and visible lights to collect pictures of the spaces on the ground. It may also use some other detectors like gamma, infrared, and UV waves when on mountains.

How do antennas receive signals?

An antenna is surrounded by the voltage that creates magnetic and electric waves. Each time the wave passes through the antenna, it induces a small voltage. That’s how the telescope antenna becomes the source of the signal to the receiver.

What is RF radiation?

The full form of RF is radio frequency. It’s a low-energy electromagnetic spectrum and includes microwaves and radio waves. Plus, radio frequency radiation can’t remove electrons from atoms easily as it’s non-ionizing radiation.

Do telescopes use reflection or refraction?

There are two types of telescopes: reflecting and refracting telescopes. Reflecting telescopes use reflection and mirrors. In contrast, refracting telescopes use refraction and lenses.

Others antenna


So what is a telescope antenna and how does it work? You just learned that the antenna is the system that works in the middle to get all these big waves from the dish to the receiver.

It has both advantages and disadvantages, but we are amazed to discover the universe of astronomers with the help of radio telescope antennas.

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