The W. M. Keck Observatory has been awarded two major grants to help build a $4 million laser system as the next leap forward in a technology which already enables ground-based telescopes to exceed the observational power of telescopes in space. The new laser, when installed on the current adaptive optics system on the Keck II telescope, will improve the performance of the system and advance future technology initiatives.
In early July the Observatory received a $1.5 million grant from the W. M. Keck Foundation, adding to a $2 million grant from the Gordon and Betty Moore Foundation awarded eight months prior for the multi-year project. Keck Observatory is charged to raise the remaining funds needed from its private supporters over the next two years.
“Ever since Galileo, astronomers have been building bigger telescopes to collect more light to be able to observe more distant objects,” said Peter Wizinowich, who leads the adaptive optics developments at Keck Observatory. “In theory, the larger the telescope the more detail you can see. However, because of the blurring caused by Earth’s atmosphere, a 10-inch or a 10-meter telescope see about the same amount of detail.”
There are two solutions to this problem, Wizinowich said: put a telescope in space or use adaptive optics technology to cancel out the distortions of the atmosphere. W. M. Keck Observatory helped pioneer the astronomical use of adaptive optics in the 1990’s, and now delivers images three to four times sharper than the Hubble Space Telescope.
Laser Guide Star Adaptive Optics, or LGS AO, uses a laser beam generated from within the Observatory to excite a layer of sodium atoms 60 miles (90 km) up, above most of Earth’s atmosphere. The sodium atoms are remnants of micro-meteors which have burned away as they hit the atmosphere. Once the specially-tuned laser hits these atoms, they light up and create an artificial star or beacon that can be used to precisely measure atmospheric turbulence and cancel out the distortions in real time.
The new laser will improve on the current laser system at Keck in several ways. Most importantly, it will be brighter. But it will also differ by being a non-pulsed laser. Researchers have discovered that non-pulsed lasers do a better job kicking sodium atoms into action and result in a more capable and efficient system.
The advanced Keck II laser will be blazing a trail for the adaptive optics system for use on the Thirty Meter Telescope, or TMT, currently in development.
“Keck can make the use of this laser routine, so that TMT can use it efficiently at first light,” said TMT Project Manager Gary Sanders. For this reason, the TMT has committed a modest amount of engineering and technical support for the Keck laser project.
The new Keck II Laser is also one of the first steps in a $50-million Next Generation Adaptive Optics system in design at Keck Observatory that will go far beyond what is currently possible. Just what will be discovered is anyone’s guess. Astronomers often find the unexpected when they gain new views into the cosmos.
Among the scientific breakthroughs which have come from the original Keck II LGS AO system is the definitive evidence of a supermassive black hole at the center of the Milky Way galaxy.
“Thanks to the resolving power of the Keck Telescopes, you can get the clearest view of the center of our galaxy and see the stars that are residing at its heart,” said Andrea Ghez, an astronomy professor at UCLA who was recently awarded the Crafoord Prize for her research involving Keck. Ghez and her team have been observing the galactic center of the Milky Way for the last 17 years to see how these stars move. Their data helped prove the existence of the black hole, and their research is far from over.
“New mysteries are being revealed to help us understand how our galaxy formed, how black holes form, how they interact with their surroundings and influence the evolution of galaxies, the fundamental building blocks of our Universe. We are seeing things that no one expected,” said Ghez.
The new laser will improve their black hole research by at least a factor of two, she said.
“The Gordon and Betty Moore Foundation is tasked to fund fundamental scientific research and Keck Observatory is an undisputed leader in revolutionizing astronomy with adaptive optics technology,” said Foundation Science Program Director Cynthia Atherton. “This project resonates with what we say on our external website: we like to take smart risks because major leaps forward in science won’t happen otherwise.”
The confidence that the Keck Foundation and the Moore Foundation have shown in Keck Observatory by partnering with us on the new laser is very significant, said Observatory Director Taft Armandroff.
“These two Foundations are the most sophisticated private funders of science today,” Armandroff said.