A Megatelescope Will Dwell
Thanks to Gordon Moore, astronomical telescope size will continue to double fast as the number of well heeled Silicon Valley foundations. The next generation, scheduled to collect its first light in 2016, is this 100 foot monster
A decade long commitment by his foundation will provide much of the three hundred million dollar cost of developing the Thirty Meter Telescope. The TMT will consist of a primary mirror with 492 individual 1.45-meter segments together measuring 30 meters in diameter, more than eight times the collecting area of the biggest instruments extant, the Keck telescopes in Hawaii. Thanks to Moore's Law, the mirror segments will be under ever more precise computer control as software and sensors co-evolve, so that they will ever more closely approximate a perfect single mirror. This revolutionary technology was developed for the 10-meter Keck mirrors in the two Keck telescopes in Hawaii
Adaptive optics (AO) will enable the Thirty Meter Telescope to exceed the resolution of the Hubble Space Telescope despite being immersed in the Earth's wobbly ocean of air. The TMT AO system will use six intense metal vapor laser beams to create six glowing pinpoints of light in a layer of sodium atoms sixty miles overhead in the Earth's ionosphere.
These bright artificial stars serve as references for measuring turbulence, allowing the AO system to compensate for blurring of starlight by light path variations in the air. This virtual guide star technology was first used to halt the twinklingof the stars through the nearly century old 100 inch Hooker telescope of Los Angeles Lick Observatory, and has since been developed further using the Palomar 5-meter and the paired Keck 10-meter telescopes.