How high-tech optics and lasers make space clear as day.
Telescopes are wonderful inventions, introduced by a spectacle maker in the 1600s and made popular by Galileo, that have allowed us a view of the heavens above us for many years. As with any technology they've progressed in leaps and bounds from the original 1.5" lens versions on the ground; making news with the Hubble telescope's 2.4m diameter in 1990.
Now though we've managed to eclipse Hubble's space-gazing performance, which took more than just a little work to eliminate some of the problems that the Hubble had. Apart from an initial misalignment of the telescope, Hubble's small lens made it difficult to observe dimly lit objects at a large distance (though it didn't have to deal with interference from Earth's atmosphere).
The atmosphere is no longer a problem for Earth-based telescopes thanks to a new laser system. It fires a beam into the atmosphere that excites sodium atoms in the air, creating an incredibly bright light source that mimics stars in outer space and allows calibration of the main telescope - giving a clearer view of space than Hubble can manage due to larger mirrors.
National Geographic have taken 14 pictures of a brand-new telescope called the Large Binocular Telescope that was built in Arizona, using twin 8.4 metre mirrors to give an equivalent resolution of a 22.8 metre telescope - using two image sensors that cost US$150,000 to build. It's an incredibly precise and powerful telescope, and just goes to show how far we've come from the original hand-held telescopes.
Head over to National Geographic's gallery of photos, and marvel at the structures that ten years from now will probably be obsolete.
Issue: 107 | December, 2009