By Emily Levesque, University of Washington
Telescope designers and builders are significant in the history of astronomical heroes for highlighting the key elements that make up our universe as we understand it today. From the physics and chemistry of stars to the study of distant galaxies, dark matter, and the structure of our universe, astronomy has made great strides in the past century with the help of telescopes.
Hubble Space Telescope
The Hubble Space Telescope, first envisioned by Lyman Spitzer and brought to life by Nancy Grace Roman, has revolutionized observational astronomy. The dawn of radio astronomy, made possible by Karl Jansky and Grote Reber, also drove home the value of multi-wavelength astronomy, revealing the immense value of studying the cosmos across the electromagnetic spectrum.
Still, many of these triumphs can be traced back to the boldness and innovation of George Ellery Hale, the famed telescope builder of the early 20th century who progressively broke his own records for decades as he built larger and larger telescopes.
Extremely Large Telescopes
When we look ahead to future discoveries that will help us answer our questions about what the universe is made of, we can see heroes that are continuing George Ellery Hale’s legacy. Today, the largest optical telescopes on the planet are the twin Keck telescopes atop Mauna Kea on Hawaii’s Big Island, and the Gran Telescopio Canarias on the island of La Palma in the Canary Islands.
These telescopes have made invaluable contributions to our study of some of the universe’s faintest and most distant objects thanks to their enormous mirrors—all three measuring about 10 meters across, or around 33 feet. At the same time, we know that even larger mirrors could offer the opportunity to push our astronomical limits even further. This is the goal of the Extremely Large Telescopes.
The Extremely Large Telescopes may not have the most creative of names, but they are exactly what they sound like. Called ELTs for short, there are three different international projects underway to build what will be, by far, the biggest optical telescopes the world has ever seen.
ELTs are telescopes with mirror diameters larger than 20 meters; this makes their collecting area at least four times the size of the Kecks!
This article comes directly from content in the video series Great Heroes and Discoveries of Astronomy. Watch it now, on Wondrium.
The Giant Magellan Telescope
Giant Magellan Telescope, with a planned diameter of 24.5 meters, or 80 feet, is being built as part of Las Campanas Observatory in Chile. Like most large telescopes, the Giant Magellan Telescope is the result of a partnership between universities and research institutes found in multiple countries—in this case, the United States, Australia, Brazil, and South Korea.
Astronomers and engineers at all of these institutions are working together to design and build the telescope, and when it’s completed these groups will have priority observing access.
Other ELTs
Similar to the Giant Magellan Telescope, the European Extremely Large Telescope, with a 39.3 meter, or 129-foot mirror, is another enormous telescope destined for Chile and built under the auspices of the European Southern Observatory.
Finally, the Thirty Meter Telescope is exactly what it sounds like, an ELT with a 30-meter, or 98-foot, diameter mirror supported by a partnership between the United States, Japan, China, India, and Canada.
The Thirty Meter Telescope will also be the only ELT to be built in the Northern Hemisphere. Since the two hemispheres give us access to different swaths of the night sky, this makes the Thirty Metter Telescope uniquely valuable as the only extremely large northern telescope.
Features of he ELTs
All three of these telescopes have mirrors that utterly dwarf previous generations of large telescopes. They utilize a technique that was unavailable to George Ellery Hale, combining smaller custom-shaped mirror segments to act as one gigantic mirror.
They also feature cutting-edge adaptive optics, using lasers to measure the tiny ripples of Earth’s atmosphere and magnetic actuators behind the mirrors to adjust its shape in real time and cancel out any atmospheric imperfections.
Assumed Contributions of the ELTs
All three telescopes are also scheduled to achieve first light—the moment when a completed telescope takes its first observations of the sky—in the mid-to-late 2020s. When they do, their combined scientific power will be utterly groundbreaking.
Their enormous mirrors and adaptive optics systems will produce images tens of times sharper than the Hubble Space Telescope. It will enable one to clearly pinpoint and study individual stars buried in crowded galaxies hundreds of millions of light-years away, probe the chemistry of the gas and dust in even more distant galaxies, and observe the motion of these galaxies in unprecedented detail to study everything from the distribution of dark matter to the expansion of the universe.
As of now, these telescopes are still in the design or construction phase– finalizing where they’ll be built, breaking ground, building the domes and support facilities, and casting, coating, and polishing the all-important glass mirrors. The heroes of these telescopes are the scientists, engineers, and support staff who make this work possible.
Common Questions about the Contributions of Telescopes
The largest optical telescopes on the planet are the twin Keck telescopes atop Mauna Kea on Hawaii’s Big Island, and the Gran Telescopio Canarias on the island of La Palma in the Canary Islands
The Extremely Large Telescopes are exactly what their name sounds like. ELTs are telescopes with mirror diameters larger than 20 meters; this makes their collecting area at least four times the size of the Kecks!
The ELTs employ a technique that combines smaller custom-shaped mirror segments to act as one gigantic mirror. These telescopes also feature cutting-edge adaptive optics, using lasers to measure the tiny ripples of Earth’s atmosphere and magnetic actuators behind the mirrors to adjust its shape in real time and cancel out any atmospheric imperfections.
