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December 4, 2006

Bachmann Fellowship supports graduate student's work on astronomical instumentation

By Tim Stephens

Mark Ammons, a graduate student in astronomy and astrophysics, has received a Bachmann graduate fellowship to support his research at the Laboratory for Adaptive Optics.

Photo of Mark Ammons

Bachmann Fellow Mark Ammons works in the Laboratory for Adaptive Optics.
Photo: T. Stephens

The fellowship is funded by the Henry Bachmann Endowed Chair for Astronomical Instrumentation, established in 2000 with a gift from Donald C. and Sally Allen in honor of Sally Allen's grandfather, Henry Bachmann, who was an instrument maker at Lick Observatory in the early 20th century.

Michael Bolte, as director of UC Observatories/Lick Observatory (UCO/Lick), holds the Bachmann Chair and selected Ammons to receive the fellowship.

"UC Santa Cruz is one of only a few institutions in the U.S. where students can get hands-on training in forefront astronomical instrumentation," Bolte said. "The Bachmann Fellowship is wonderful for helping to attract the very best young instrumentalists to Santa Cruz for their studies."

Ammons is currently working on several projects, including adaptive optics instrumentation for extremely large telescopes. Adaptive optics (AO) sharpens the vision of ground-based telescopes by counteracting the blurring effects of turbulence in the Earth's atmosphere. UC is one of three partners currently designing a 30-meter telescope that will be equipped with an advanced AO system. It will have a view of the heavens that is more than 10 times sharper than that of the Hubble Space Telescope, Bolte said.

"In the Laboratory for Adaptive Optics, we have a mockup of a 30-meter telescope that has been scaled down to fit in the lab, and we have been testing different adaptive optics techniques for future telescopes," Ammons said.

Current AO systems use a single point-source of light -- either a bright star or an "artificial guide star" created by a laser -- as a reference for measuring atmospheric blurring. The system then calculates the corrections needed to counteract that distortion and applies the corrections by bouncing the light gathered by the telescope off a deformable mirror. This process is repeated hundreds of times per second to keep up with the constantly changing distortions caused by atmospheric turbulence. With the systems now in use, the correction is only applied over a small area of the sky.

Ammons is working on a project to develop advanced AO technology for the giant telescopes of the future using an approach called "multiconjugate" AO. The goal is to extend the corrections over a wide field of view by using multiple laser guide stars. This technique will be needed for the giant telescopes now in the planning stages.

Ammons also plans to use adaptive optics on existing telescopes to address questions regarding star formation and the buildup of galaxies in the early universe. His adviser is Claire Max, professor of astronomy and astrophysics, director of the Center for Adaptive Optics, and principal investigator of the Laboratory for Adaptive Optics.

The first Bachmann Graduate Fellow was Andrew Sheinis, who worked on instruments for the Keck Observatory under the guidance of Joseph Miller, professor of astronomy and astrophysics and former director of UCO/Lick. Sheinis is now a faculty member leading the instrumentation program at the University of Wisconsin.

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