Daylight operation of a sodium laser guide star

Michael Hart, Stuart Jefferies, Neil Murphy

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

2 Scopus citations


We report photometric measurements of a sodium resonance guide star against the daylight sky when observed through a tuned magneto-optical filter (MOF). The MOF comprises a sodium vapor cell in a kilogauss-level magnetic field between crossed polarizers and has a very narrow transmission profile at the sodium D2 resonance of approximately 0.008 nm. Our observations were made with the 1.5 m Kuiper telescope on Mt. Bigelow, AZ, which has a separately mounted guide star laser projecting a circularly polarized single-frequency beam of approximately 6.5 W at 589.16 nm. Both the beam projector and the 1.5 m telescope were pointed close to zenith; the baseline between them is approximately 5 m. Measurements of the guide star were made on the morning of 2016 March 24 using an imaging camera focused on the beacon and looking through the full aperture of the telescope. The guide star flux was estimated at 1.20×106 photon/m2/s while at approximately 45 minutes after sunrise, the sky background through the MOF was 1100 photon/m2/s/arcsec2. We interpret our results in terms of thermal infrared observations with adaptive optics on the next generation of extremely large telescopes now being built.

Original languageEnglish (US)
Title of host publicationAdaptive Optics Systems V
EditorsEnrico Marchetti, Jean-Pierre Veran, Laird M. Close
ISBN (Electronic)9781510601970
StatePublished - 2016
EventAdaptive Optics Systems V - Edinburgh, United Kingdom
Duration: Jun 26 2016Jul 1 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherAdaptive Optics Systems V
Country/TerritoryUnited Kingdom


  • Daylight observing
  • Extremely large telescopes
  • Sodium laser guide star
  • Thermal infrared
  • Wave-front sensing

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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