Observation of space and further study of celestial bodies is one of the main functions of astronomical observatories and telescopes. Dozens of impressive telescopes on Earth help scientists uncover and study the mysteries of the universe. In this article, we will present ten of the largest telescopes on the planet, which play a crucial role in modern astronomy.
10. Hobby Eberly
The dome of the Hobby-Eberly Telescope sits in front of a backdrop of blue sky. The interior of the George T. Abell Gallery, where visitors can learn about HET and view the telescope, is illuminated. Credit: Ethan Tweedie
Location: Texas, USA
Diameter: 32 feet (10 meters)
The success of the Hobby Eberly telescope can be attributed, in particular, to its unique design, which distinguishes it from other optical telescopes. A vital aspect of the design is the angle of the mirror, which is located at an angle of 55 degrees to the horizon. Despite this seemingly limited angle, the telescope can still observe 70% of the visible sky thanks to its rotating mechanism. The telescope mirror consists of 91 hexagonal segments that collect visible light. The Hobby Eberly telescope made a fantastic discovery – it detected light from a quasar that formed so long ago that the Earth was not yet in its current state. Quasars are luminous objects that receive energy from supermassive black holes.
9. Keck telescopes
Location: Maunakea, Hawaii
Type: optical and infrared
Diameter: 32.8 feet (10 meters)
The twin telescopes of the Keck Observatory are located on the surface of the Earth. Still, they have an extraordinary ability to penetrate space, surpassing even the famous Hubble telescope. Approximately 25% of the astronomical observations made by American astronomers are carried out with the help of Keck telescopes, considered the most scientifically fruitful ground-based telescopes. Using optical and infrared telescopes, the Keck Observatory produces beautiful images of celestial bodies in visible and infrared light. This combination of instruments allows astronomers to perceive the universe in the deep infrared and reveal unique events. These events include the formation of stars, which produce visible light, and the subsequent heating of gases near them, which can be observed through infrared radiation. Near the equator is an observatory on top of Hawaii’s inactive Mauna Kea volcano. Two telescopes make up the observatory, each consisting of 36 mirrors combined into one wide panel. To avoid the effects of heat on infrared observations, the telescopes are hidden in insulated domes and operate at sub-zero temperatures.
8. Gran Telescopio Canarias (GTC)
The Gran Telescopio Canary Islands is located at the Roque de los Muchachos Observatory in La Palma. Credit: Daniel Lopez/IAC
Location: La Palma, Spain
Diameter: 34.1 feet (10.4 meters)
A telescope on the island of La Palma in Spain has discovered a highly dense cluster of galaxies.
7. South African Large Telescope (SALT)
A view of the Southern African Large Telescope. Credit: Simon Fishley
Location: Karoo, South Africa
Diameter: 36 feet (11 meters)
The design of SALT is strikingly similar to the Hobby Eberly telescope, which is also a large telescope. However, SALT has undergone significant improvements to improve the field of view and image quality. Although both telescopes have the same number of hexagonal panels, using additional metal layers on the mirrors has enhanced SALT’s short-wavelength sensitivity. A remarkable achievement of SALT is the discovery of the primordial white dwarf pulsar.
6. Atacama Large Millimeter/Submillimeter Array (ALMA)
A stunning drone shot of ALMA showing one of the many different array configurations. Credit: Juan Carlos Rojas – ALMA (ESO/NAOJ/NRAO)
Location: Atacama Desert, Chile
Diameter: 39.4 feet (12 meters)
The Atacama Large Millimeter/Submillimeter Array, ALMA for short, consists of 66 radio telescopes that study millimeter and submillimeter waves in space. This impressive array consists of 54 antennas with a diameter of 39.4 feet (12 meters) and another 12 antennas with a diameter of 23 feet (seven meters), making it an extremely powerful resource for astronomers. Astronomers now have access to unprecedented capabilities thanks to the radio telescope’s interferometer. ALMA can gather information from a wide range of the electromagnetic spectrum that was once largely unexplored. This allows researchers to observe events in space that were previously unavailable with other instruments. Thanks to ALMA’s advanced telescopes, researchers made a groundbreaking discovery: the most distant oxygen ever detected in space. This discovery was made possible by ALMA’s exceptional ability to gather data from vast distances, recording the signal from ionized oxygen in the galaxy MACS1149-JD1, located an astonishing 13.28 billion light-years from our planet. This oxygen existed in the universe’s distant past, and this discovery opened up new opportunities for further exploration of the remotest corners of space.
5. Giant Magellan Teleskope (GMT)
Expected to see first light in 2021, the Great Magellan Telescope (GMT) will be the largest optical telescope in existence. It will be a segmented mirror telescope employing seven of today’s largest stiff monolith mirrors as segments. Six off-axis 8.4-metre or 27-foot segments surround a central on-axis segment, forming a single optical surface 24.5 metres, or 80 feet, in diameter with a total collecting area of 368 square metres. The GMT will have a resolving power 10 times greater than the Hubble Space Telescope. Credit: Giant Magellan Telescope – GMTO Corporation.
Location: Atacama Desert, Chile
Diameter: 80 feet (24.5 meters)
GMT, scheduled for completion in 2029, can produce images ten times sharper than Hubble.
4. Thirty Meter Telescope (TMT)
TMT simulation. Credit: M3 Engineering, Telescopio de Treinta Metros
The largest optical-infrared telescope in the world is located on Mauna Kea, Hawaii. This impressive project, known as the TMT (Millennium Magellan Telescope), was made possible by the cooperation of many countries, such as Japan, the United States, Canada, China, and India, who pooled their resources to create a one-of-a-kind astronomical instrument. Its creation is evidence of the power of international cooperation in scientific discoveries. At the center of the TMT lies its primary mirror, made of 492 hexagonal panels and an impressive 98 feet (30 meters) in diameter. These 56.6-inch (1.44-meter) panels are separated by just 2.5 millimeters (0.1 inch). Located 13,163 feet (4,012 meters) above sea level, the TMT was designed to conduct a broad survey of celestial bodies, including the black holes at the center of our galaxy and other galaxies. The scale of this project brings together different nations and has the potential to expand our understanding of space. This is due to the incomparable observational advantage of the telescope’s enormous size and its exceptional skill in interpreting infrared radiation.
3. Square Kilometer Array (SKA)
CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP) Telescope. Credit: ATNF
Location: Australia and South Africa
Type: headlights, radio
Diameter: 512 x 49.2 feet (512 x 15 meters)
The scope of this monumental work includes two colossal radio telescopes in Australia and South Africa. Each telescope is proposed to be 512 x 49.2 feet (512 x 15 meters) in diameter. Although the size of each telescope may not be the largest, this project is notable for its scale and the large number of stations involved. This ambitious project is identified by the number “333. The Karoo in South Africa and the Murchison Shire in Western Australia were explicitly chosen as locations for this project because of their remoteness, far from metropolitan areas. The region of Western Australia was designated to host the largest group of telescopes, which initially included 512 stations.
In contrast, South Africa will be home to a smaller array of 200 stations. This endeavor aims to produce sets of telescopes that will possess extraordinary speed and sensitivity in the study of space. The researchers predicted that these sets would be a hundred times more sensitive than today’s advanced radio telescopes, and their ability to probe the sky would be reduced by a million times. The completion date of this project is expected to be 2028, and the sets of telescopes will be used for space exploration for the next fifty years.
2. Extremely Large Telescope (ELT)
The Extremely Large Telescope (ELT) will sit on top of Cerro Armazones, approximately 3046 metres high in Chile’s Atacama Desert, surrounded by breathtaking views of the plains below. This image (an artistic rendering) shows how the telescope will look like on top of the mountain. The levelling of the summit of Cerro Armazones, in preparation for the construction of the ELT, was completed in 2015. Credit: ESO
Location: Atacama Desert, Chile
Diameter: 128 feet (39.3 meters)
Developed by the European Southern Observatory (ESO), the Extremely Large Telescope (ELT) has impressive specifications and ambitions. Its location in the Atacama Desert, Chile, was chosen for its excellent conditions for astronomical observations. The telescope building is expected to be completed in 2027.
The main purpose of this telescope is to find and study Earth-like planets and search for life outside our solar system. With a sizeable specular surface area of 10,527 square feet (978 square meters), the ELT can gather 100,000,000 times more light than the human eye, making it an ideal tool for studying distant objects in space. The telescope will be in a huge rotating dome, 262 feet (80 meters) tall and weighing approximately 6,000 tons.
The foundation for this huge telescope was completed in early 2022, marking progress in implementing this ambitious project.
1. 500-metre Spherical Telescope (FAST)
In this photo,released by the Xinhua News Agency on 24 Sept. 2016, an aerial view shows the Five-hundred-meter Aperture Spherical Telescope (FAST) in the remote Pingtang county in southwest China’s Guizhou province. Credit: Liu Xu, Xinhua News Agency.
Location: Guizhou, China
Diameter: 1,640 feet (500 meters)
FAST opened in 2020 and is currently the world’s largest single-dish ground-based telescope.
Banner image: ESO