Next-generation ground telescopes received priority designation from a long-awaited report by the National Academy of Sciences. They would join a host of existing ground telescopes and smaller space telescopes already peering at supernovas, galaxies and other distant objects in the starry skies.
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 some of the present and future giants among ground-based telescopes that provide scientists a glimpse of the past universe through time and space.
Large Synoptic Survey Telescope (LSST)
A new ground-based observatory that would scan the entire available sky every three nights from Chile could see first light by 2014. The $465-million Large Synoptic Survey Telescope would give astronomers their best view ever of how billions of faint starry-sky objects change over time. It could also tackle questions relating to the nature of dark energy, and perhaps track space rocks that might collide with Earth in the future.
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.
SALT/Southern African Large Telescope consortium
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.
Keck I and II Telescopes
The twin 33-foot (10-meter) telescopes at the W. M. Keck Observatory represent the second largest optical telescopes on Earth, located close to the summit of Hawaii’s Mauna Kea. Each instrument’s main mirror consists of 36 hexagonal segments that work together.
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.
Gran Telescopio Canarias (GTC)
A 34-foot (10.4-meter) telescope located on La Palma of Spain’s Canary Islands seized the top spot as the world’s biggest ground-based optical telescope in 2009. A main mirror that consists of 36 hexagonal segments contains some of the smoothest surfaces ever made.
The telescope also has several support instruments such as CanariCam, a camera capable of examining mid-range infrared light emitted by stars and planets. The CanariCam also has the unique ability to figure out the direction of polarized light and use coronagraphy to block out bright starlight and make fainter planets more visible.
NAIC – Arecibo Observatory, a facility of the NSF
One of the world’s most recognizable ground-based telescopes has resided as a huge 1000-foot (305-meter) radio reflector dish near Arecibo, Puerto Rico since 1963. The Arecibo radio telescope still represents the largest single-aperture telescope ever constructed, with its spherical reflector consisting of 40,000 aluminum panels each 3 feet by 6 feet.
The huge reflector helps make Arecibo an incredibly sensitive radio telescope, capable of homing in on a faint radio source within just several minutes of observation. Such radio sources include distant quasars and galaxies that emit radio waves which only reach Earth 100 million years later.
These are some of the biggest telescopes in the world.
