Tomographic reconstruction of stellar wavefronts from multiple laser guide stars

Christoph Baranec, Michael Lloyd-Hart, N. Mark Milton, Thomas Stalcup, Miguel Snyder, Roger Angel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

12 Scopus citations


Experiments have been carried out at the MMT telescope in June 2005 and again in April 2006 to validate open loop tomographic wavefront reconstruction using five dynamically refocused Rayleigh laser beacons (RLGS) and multiple tilt natural guide stars (NGS). Wavefront sensing in this manner is recognized as a critical precursor to the development of adaptive optics for Extremely Large Telescopes. At the MMT, wavefronts from the laser beacons are recorded by five 60-element Shack-Hartmann sensors implemented on a single CCD. A wide-field camera measures image motion from multiple field stars to calculate global tilt and distinguish effects of contributions to second order aberrations from low and high altitude turbulence. Together, the signals from these sensors are used to estimate the first 45 Zernike modes in the wavefront of a star within the LGS constellation. The reconstruction is compared off line to simultaneous wavefront measurements made of the star with a separate Shack-Hartmann sensor. We will present the results in this paper and quantify the wavefront improvement expected from tomographic adaptive optics correction.

Original languageEnglish (US)
Title of host publicationAdvances in Adaptive Optics II
StatePublished - 2006
EventAdvances in Adaptive Optics II - Orlando, FL, United States
Duration: May 24 2006May 31 2006

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume6272 I
ISSN (Print)0277-786X


OtherAdvances in Adaptive Optics II
Country/TerritoryUnited States
CityOrlando, FL


  • Adaptive optics
  • Laser guide stars
  • Multi-conjugate adaptive optics
  • Tomography
  • Wavefront sensors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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