A high-Strehl low-resolution optical imager (BESSEL): A measurement of the inner scale of turbulence

Mary Anne Peters, Laird M. Close, Tom Stalcup, Matt Rademacher, Grover A. Swartzlander, Erin L. Ford, Rukiah S. Abdul-Malik

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


We have constructed a high-speed image stabilization system, BESSEL, that is capable of performing wavefront correction at a rate exceeding 1 kHz. BESSEL achieved on-sky Strehl ratios of 98-99% at 800 nm as we approached the inner scale of atmospheric turbulence when the refractor telescope aperture was stopped down to 25.4 mm (̃r0/2). This is better than expected from Kolmogorov theory, indicating that at D ̃r0/2 we are within the inner scale of turbulence. Utilizing high Strehls and the technique of roll subtraction enabled BESSEL to resolve the binary, ADS 10418AB, with separation of only 0.71 ?/D and a delta magnitude of ̃3 mags at 800 nm. BESSEL's capability to produce high Strehls ratios means that the instrument can be used to test the performance of interference/phase coronagraphs on-sky for the first time. Integrated with an optical vortex coronagraph, BESSEL is capable of nulling the first airy ring of Betelgeuse by more then a factor of ten.

Original languageEnglish (US)
Title of host publicationAdaptive Optics Systems
StatePublished - 2008
EventAdaptive Optics Systems - Marseille, France
Duration: Jun 23 2008Jun 26 2008

Publication series

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


OtherAdaptive Optics Systems


  • Coronagraphy
  • Instrumentation: adaptive optics
  • Stars: binaries
  • Stars: planetary systems

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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