Three planned optical telescopes in the 98-foot (30-meter) range would house some of the biggest mirrors yet for collecting light from distant cosmic objects. And proposed radio telescope would dwarf predecessors by using many antenna stations to create a total collecting area of a square kilometer, or 0.4 square miles.
Here's a look at ten of the present and future giants among ground-based telescopes that provide scientists a glimpse of the past universe through time and space.
10. Large Synoptic Survey Telescope (LSST)
The optical telescope would image each region of the sky 1,000 times over 10 years with an almost 28-foot (8.4-meter) aperture. It represented a top priority among ground projects slated for the next 10 years in the Astro2010 Decadal Survey by the National Academy of Sciences.
9. South African Large Telescope (SALT)
This 30-foot (9.2-meter) telescope represents the largest ground-based
optical instrument in the southern hemisphere, and concentrates on
spectroscopic surveys. A main mirror consists of 91 hexagonal mirrors
that join together to form the larger hexagonal primary —not unlike the
Hobby-Eberly Telescope (HET) in Fort Davis, Texas.
Like HET, SALT also has a fixed-angle design that has complicated
observations since it began operation in 2005. But the instrument can
still view about 70 percent of the sky observable from Sutherland, South
Africa.
8. Keck I and II Telescopes
Keck I became operational in 1993, followed just a few years later by Keck II in 1996. The combined observatory has helped astronomers examine events such as last year's impact on Jupiter. It also deployed the first laser guide star adaptive optics system on a large telescope in 2004, which creates an artificial star spot as a reference point to correct for atmospheric distortions when viewing the sky.
7. Gran Telescopio Canarias (GTC)
One of the largest ground-based astronomy tools comes in the form of the 39-foot (12-meter) radio antennas that will total 66 by 2012, to make up ALMA's main array. Each antenna weighs more than 100 tons each and requires huge crawler vehicles to move it to Chile's Chajnantor plain at an altitude 3 miles up. This will ultimately help make ALMA the largest and most sensitive radio telescope ever, at least until a new contender emerges.
The antenna array can also undergo different configurations by moving individual antennas around. A compact configuration would place all the antennas within an area less than 1,000 feet across, or within an extended configuration with a maximum distance of separation between the antennas of almost 10 miles. This will allow the array to study everything from the cosmic "dark ages" billions of years ago to the processes of star and planet formation.
4. Giant Magellan Telescope (GMT)
One of the next ground-based optical telescopes will take the form of the $1.1-billion Giant Magellan Telescope with an 80-foot (24.5-meter) main mirror that consists of seven segments. One 8.4-meter segment would sit in the middle, surrounded by the other six segments that have a unique curved shape not unlike that of a potato chip.
The large main mirror would dwarf the current generation of 26 to 33-foot (8 to 10-meter) telescopes and produce images about 10 times sharper than the Hubble Space Telescope. If fully funded, the telescope could find a home at the Las Campanas Observatory in La Serena, Chile and begin full operations by 2024.
3. Thirty Meter Telescope (TMT)
Another of the next-gen contenders for biggest optical telescope on
Earth is the Thirty Meter Telescope. The $1.4-billion telescope's
98-foot (30-meter) aperture would allow for more than 9 times the
collecting area of the largest optical telescopes such as the Keck
Telescopes, and could provide 12 times sharper resolution than the
Hubble Space Telescope.
But TMT and other extremely large optical telescopes would not replace space telescopes. Hubble's successor, NASA's James Webb Space Telescope, would find targets for Earth-based giants such as TMT to study in more detail. The Thirty Meter Telescope is slated to join the Keck Telescopes and other instruments on Mauna Kea in Hawaii and commence full operations by 2025-2030.
But TMT and other extremely large optical telescopes would not replace space telescopes. Hubble's successor, NASA's James Webb Space Telescope, would find targets for Earth-based giants such as TMT to study in more detail. The Thirty Meter Telescope is slated to join the Keck Telescopes and other instruments on Mauna Kea in Hawaii and commence full operations by 2025-2030.
2. Square Kilometer Array (SKA)
A follow-up to radio telescopes such as ALMA is a telescope capable of
collecting data over one square kilometer. The aptly-named Square
Kilometer Array would become the clear king of radio telescopes, with 50
times the sensitivity of any radio telescope ever built. Such power
could examine signals from the younger universe of 12 billion years ago.
Current plans call for either 30 stations with a collecting area of 656 feet (200 meters) each, or 150 stations each equivalent to a 295-foot (90-meter) telescope. South Africa and Australia have already begun jostling in a bid to play host to the $2 billion behemoth, scheduled for completion around 2020. It co-ranked as the highest priority project in the European Astronet Decadal Survey, along with the European Extremely Large Telescope.
Current plans call for either 30 stations with a collecting area of 656 feet (200 meters) each, or 150 stations each equivalent to a 295-foot (90-meter) telescope. South Africa and Australia have already begun jostling in a bid to play host to the $2 billion behemoth, scheduled for completion around 2020. It co-ranked as the highest priority project in the European Astronet Decadal Survey, along with the European Extremely Large Telescope.
1. European Extremely Large Telescope (E-ELT)
No ground-based optical telescope contender can currently match the design proposal for the European Extremely Large Telescope.
Its 138-foot (42-meter) mirror would put it easily beyond the Thirty
Meter Telescope and Giant Magellan Telescope, with a length reaching
almost half a soccer field. Five mirrors consisting of almost 1,000
hexagonal segments would make up the primary mirror, and give
Earth-bound astronomers the sharpest view ever of the cosmos in the
visual-light spectrum.
Cerro Armazones in Chile will be the future home of the world's largest optical telescope. The $1.3-billion E-ELT would see first light around the same time as its smaller next-gen cousins in 2018.
Cerro Armazones in Chile will be the future home of the world's largest optical telescope. The $1.3-billion E-ELT would see first light around the same time as its smaller next-gen cousins in 2018.