Discover the Top 7 Largest Telescopes on Earth

Written by Em Casalena
Published: May 28, 2023
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It’s pretty amazing that we live in a time when science and technology have come together to create enormous, powerful telescopes. These telescopes are our eyes that look into the universe, allowing us to learn more about the expanse of space. But which telescopes are the largest and most powerful? In this list, we’ll take a look at some of the largest telescopes in the world.

1. Extremely Large Telescope

Location: The Atacama Desert in Chile

The name isn’t particularly creative, but it is one of the largest telescopes in the world. The European Southern Observatory (ESO) is currently undertaking the Extremely Large Telescope (ELT). It is a large-scale project to build one of the most technologically sophisticated optical telescopes. On Cerro Armazones, a peak in Chile’s Atacama Desert renowned for its excellent observation conditions, the ELT is situated. The desert is a popular spot for many of the telescopes on this list.

Exploring the universe in unprecedented detail is the main goal of the ELT. The telescope aspires to answer key astrophysical and cosmological issues with its vast size and cutting-edge technology. Exoplanet research, galaxies’ genesis and development, and the nature of dark matter and dark energy can all be done because of this magnificent piece of technology.

This telescopes has a primary mirror with a diameter of 128 feet. The ELT will be the biggest optical or near-infrared telescope ever built. The enormous amount of light that will be collected by this massive mirror will allow astronomers to examine celestial objects with unmatched sensitivity and precision. The segmented mirror design of the telescope improves the telescope’s capacity to adjust to air turbulence. This allows it to produce pictures that are crisper and sharper.

The Impressive Features of the ELT

The ELT’s adaptive optics technology is among its most impressive features. Astronomers can observe with unparalleled clarity thanks to this device, which actively corrects for atmospheric imperfections. It uses deformable mirrors and sophisticated algorithms to instantly correct for air turbulence, producing images that are significantly crisper than those produced by earlier telescopes.

Additionally, the ELT will be equipped with a variety of cutting-edge scientific tools, each designed to achieve a particular research objective. Astronomers will be able to investigate a variety of cosmological events using these instruments since they will span a wide spectrum of wavelengths, from the visible to the mid-infrared.

The ELT is a genuinely exceptional and ground-breaking observatory due to its enormous size, sophisticated adaptive optics system, and cutting-edge instruments. By solving puzzles and revealing fresh perspectives on the nature of the world we live in, it is poised to fundamentally alter how we perceive the cosmos. The ELT is expected to be a source of new knowledge for astronomers all across the world as construction moves forward and it is put into use, leading to significant improvements in the science of astronomy.

2. Gran Telescopio Canarias Reflector

Location: La Palma, Spain

The Roque de los Muchachos Observatory on the Spanish island of La Palma is home to the important astronomical observatory known as the Gran Telescopio Canarias (GTC) reflector, sometimes referred to as the Great Canary Telescope. It is one of the biggest single-aperture optical telescopes in the world, and the Instituto de Astrofsica de Canarias (IAC) is in charge of running it.

The main goal of the GTC is to carry out advanced astronomical research in a variety of fields. It has cutting-edge equipment to explore a range of cosmological phenomena, including the nature of dark matter, the characteristics of distant galaxies, the observation of exoplanets, and star populations.

The telescope is one of the biggest optical telescopes in the world, with a main mirror that measures 34 feet in diameter. A massive amount of light is intended to be collected by the mirror, which is made up of 36 hexagonal pieces, each measuring six feet across. As a result, the GTC is able to reach remarkable sensitivity, allowing astronomers to examine dim and far-off cosmic objects.

What Makes the GTC Unique?

The GTC stands out not just for its remarkable size but also for its cutting-edge technology and adaptability. The telescope uses cutting-edge adaptive optics technology to account for atmospheric aberrations, improving the observations’ clarity and resolution. It also provides a wide range of scientific tools, including spectrographs and cameras, to meet the unique demands of astronomers and let them explore a range of fields of study.

The GTC is also well known for its collaborative spirit. It accepts applications from astronomers from all around the world to use its resources after a competitive proposal procedure. This promotes international collaboration and information sharing by giving scientists from many institutions and nations access to the telescope and enabling them to perform ground-breaking research.

A stunning illustration of astronomy technology proficiency is the Gran Telescopio Canarias Reflector in Spain. Its enormous size, cutting-edge adaptive optics, and adaptable equipment make it a useful tool for scientists trying to solve the universe’s riddles. The GTC continues to make a substantial contribution to our comprehension of the universe by allowing a variety of astronomical investigations and encouraging cooperation.

An observatory located in La Palma, Spain.

The GTC (pictured) is one of the most popular telescopes in the world for research into space.


3. 500-Meter Aperture Spherical Telescope

Location: Guizhou, China

Due to its exceptional size and cutting-edge capabilities, the 500-Meter Aperture Spherical Telescope (FAST) in China has drawn a lot of attention. FAST, which replaced the Arecibo Observatory as the biggest single-dish radio telescope in the world, is located in the Guizhou Province of China.

The main goal of FAST is radio astronomical universe exploration. It’s intended for the detection and investigation of radio waves generated by celestial bodies, such as pulsars, galaxies, and hydrogen gas. FAST enables astronomers to study cosmic occurrences, comprehend the structure and development of galaxies, and look for alien intelligence by detecting radio emissions.

A distinguishing quality of the telescope is its enormous size, which measures 1,640 feet in diameter. It looks like a huge bowl that absorbs radio waves from space because of its concave form. FAST can detect weak and far-off signals thanks to its unmatched sensitivity, which is made possible by its enormous size. The telescope’s enormous size also makes it possible for it to discern minute features and map the radio sky with outstanding accuracy.

The Grand Capabilities of FAST

Beyond its enormous size, FAST is distinctive. It has a revolutionary dynamic surface system made up of hundreds of panels, each with its own control. These panels may be changed in real-time to account for heat and gravitational impacts while maintaining the precise form of the telescope’s surface. The telescope’s great accuracy and ideal focus are maintained thanks to this adaptive mechanism, which improves the caliber of the observations.

FAST can quickly survey a significant section of the sky thanks to its extraordinarily broad field of vision. This feature makes it ideal for carrying out sky surveys, finding fresh sources, and keeping an eye on fleeting phenomena like pulsar emissions.

FAST’s participation in the search for extraterrestrial intelligence (SETI) effort is another remarkable feature. In order to look for potential artificial radio signals from advanced civilizations beyond Earth, the telescope incorporates a specific SETI survey mode. Its remarkable sensitivity and broad frequency coverage make it an invaluable tool in the search to understand the workings of the cosmos and perhaps find evidence of other highly developed life forms.

China’s 500-Meter Aperture Spherical Telescope is a significant development for radio astronomy. It is a special and potent tool for astronomical research because of its enormous size, sophisticated active surface system, and SETI capabilities.

4. Thirty Meter Telescope

Location: Mauna Kea, Hawaii, United States

An ambitious astronomical undertaking known as the Thirty Meter Telescope (TMT) is scheduled to be built on Mauna Kea’s summit in Hawaii. With the TMT, scientists will have access to one of the most cutting-edge ground-based optical and infrared telescopes in the world, offering views with previously unheard-of clarity and sensitivity.

The TMT’s main objective is to investigate the universe at various wavelengths, from ultraviolet to mid-infrared. The telescope will gather a remarkable amount of light with its massive 30-meter (or 98 feet) segmented mirror, enabling astronomers to investigate celestial objects with incredible detail and precision. The TMT will be able to observe dim and far-off objects, such as galaxies, star clusters, and exoplanets.

The TMT stands out not just for its enormous size but also for its cutting-edge technology and adaptive optical capabilities. Modern adaptive optics technology will be employed in the telescope to correct for distortions brought on by the atmosphere of Earth. This method, along with the big mirror and advanced instrumentation, will allow the TMT to provide images with a degree of quality unmatched by any other telescope at this time.

Controversies Surrounding the TMT

The TMT’s distinctive features and capabilities will enable ground-breaking scientific findings in a number of astronomical fields, including the study of the physics of black holes, the study of the formation and evolution of galaxies, the study of exoplanets, and the nature of dark matter and dark energy.

It’s crucial to keep in mind that the TMT’s development has encountered several difficulties and controversies because of worries about the impact on Mauna Kea’s cultural heritage and natural environment. Mauna Kea is regarded by native Hawaiians as a sacred location. Legal battles and protests around the project have slowed down construction, but the project appears to still be in progress as of 2023.

The TMT and its observatory (pictured) have been the subject of a lot of controversy in Hawaii.

©EastVillage Images/

5. Square Kilometre Array

Location: South America and Australia

Another large-scale multinational initiative is the Square Kilometre Array (SKA), which aspires to build the biggest and most accurate radio telescope ever. It ushers in a new age of radio astronomy and offers previously unheard-of tools for examining the cosmos.

The SKA is built to examine radio waves generated by celestial objects in order to investigate a variety of astrophysical processes. Scientists will be able to use it to map hydrogen in far-off galaxies, examine the early cosmos, look into the secrets of pulsars and black holes, and look into the origin and development of galaxies.

The SKA is distinctive due to its enormous size and sensitivity. A total collecting area of around one square kilometer (or 3281 square feet) will be covered by thousands of individual radio antennas dispersed across considerable distances. Two distinct regions (SKA-Mid in South Africa and SKA-Low in Australia) will receive the antennas.

The SKA will be able to capture a large spectrum of radio signals since it will operate over a wide range of frequencies, from tens of megahertz to several gigahertz. Due to its adaptability, it is suitable for a wide range of astronomical research.

The SKA will use cutting-edge technology in addition to its massive size to analyze and analyze the vast quantity of data it gathers. Unprecedented data rates will be generated by the telescope, necessitating advanced supercomputing and data processing technologies to handle and derive useful scientific insights. The SKA project is an international cooperative endeavor comprising several nations and organizations.

6. Giant Magellan Telescope

Location: The Atacama Desert in Chile

An innovative astronomical observatory called the Giant Magellan Telescope (GMT) is being built in Chile’s Atacama Desert. Once finished, it will rank among the biggest optical telescopes in the world. It will be a significant participant in the astronomical community.

The GMT’s main objective is to study the universe in unparalleled depth. The telescope will offer outstanding sensitivity and resolution. This is because of its massive main mirror, which is made up of seven separate pieces. Each piece measures approximately 27 feet in diameter. The total area of the mirror segments’ collecting surfaces will be 80 feet. This will provide the GMT with a phenomenal capacity for light gathering and analysis.

The GMT stands out because of its distinctive appearance and cutting-edge technologies. The innovative “segmented mirror” technique used by the telescope combines the advantages of both big monolithic mirrors and smaller segmented mirrors. While keeping the benefits of separate segments in terms of manufacture and control, this design enables outstanding accuracy. In order to adjust for atmospheric imperfections, the GMT will use cutting-edge adaptive optics technology. This will give astronomers access to pictures that are substantially sharper and clearer than ever before.

The GMT’s partnership with prominent astronomical institutes and nations is another aspect of it that is very promising. The telescope is a multinational undertaking with collaborators from countries including the United States, Australia, Brazil, and South Korea. Through this international partnership, access to a wide range of resources and experience is guaranteed. It encourages creativity and advances in cutting-edge scientific research.

When fully operational, the GMT will support a variety of astronomical research projects. This will include research into exoplanets, the composition of dark matter, the development of galaxies, and the search for alien life. The telescope is a revolutionary tool ready to redefine our understanding of the cosmos.

7. Atacama Large Millimeter Array

Location: The Atacama Desert in Chile

A ground-breaking astronomical observatory called the Atacama Large Millimeter Array (ALMA) is situated in Chile’s Atacama Desert. With the ability to observe millimeter and submillimeter wavelengths, it is one of the most powerful radio telescopes in the whole world. International partners, including as those from Europe, North America, and East Asia, collaborate on ALMA.

Astronomers may investigate a variety of astrophysical events by using ALMA to probe the cosmos at longer wavelengths. The superior interferometric array design of ALMA is what sets it apart. It is made up of 66 high-precision antennas arranged in an array that work together to form a single, extremely sensitive telescope. The antennas may be set up in a variety of ways, from tiny to extended, offering a variety of resolutions and enabling astronomers to record both minute details and more comprehensive surveys of the sky.

The 39-foot-diameter ALMA antennas are placed in key locations all across the Chajnantor Plateau. A single antenna with a diameter equal to the greatest distance between the antennas would have one angular resolution. However, ALMA achieves a very high angular resolution by integrating the signals received by numerous antennas. ALMA can examine cosmological processes with unparalleled accuracy and detail because of its special interferometric configuration.

The photo featured at the top of this post is © Allexxandar/

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About the Author

Em Casalena is a writer at A-Z Animals where their primary focus is on plants, gardening, and sustainability. Em has been writing and researching about plants for nearly a decade and is a proud Southwest Institute of Healing Arts graduate and certified Urban Farming instructor. Em is a resident of Arizona and enjoys learning about eco-conscious living, thrifting at local shops, and caring for their Siamese cat Vladimir.

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