Hokupa`a Anisoplanatism and Mauna Kea Turbulence Characterization

Flicker, Ralf; Rigaut, F.

doi:10.1086/342183

Cited by 10 publications

(6 citation statements)

References 15 publications

(8 reference statements)

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“…This is much lower than the assessment of the effective turbulence height of 6.5 km reported by Racine and Ellerbroek (1995). Our result is more consistent with, but still lower than, the height of 3.5 km evaluated at Gemini using the Hokupa'a AO system (Flicker, Rigaut 2002). Actual effective height of the turbulent layer may well be varying from night to night, as well as throughout the night.…”

Section: Isoplanatic Anglesupporting

confidence: 83%

Performance of Subaru Cassegrain Adaptive Optics System

Takami

Takato

Hayano

et al. 2004

Publications of the Astronomical Society of Japan

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The design and performance of the Cassegrain Adaptive Optics (AO) system for the 8.2 m Subaru Telescope are reported. The system is based on a curvature wavefront sensor with 36 photon-counting avalanche photodiode modules and a bimorph wavefront correcting deformable mirror with 36 driving electrodes. The engineering first light of the AO system took place in 2000 December. The AO system has been in service since 2002 April for two open-use instruments, an infrared camera and spectrograph and a coronagraph imager with adaptive optics. The Strehl ratio in the K-band is around 0.3 for bright guide stars under 0. 4 K-band seeing condition. The control loop performs with 2060 corrections per second. High sensitivity of the wavefront sensor allows significant improvement in the image quality, even for faint guide stars down to R = 18 mag. The FWHM of stellar images in a globular cluster was measured to derive an estimation of the isoplanatic angle and was found nearly constant out to 30 from the guide star, indicating that the height of the effective turbulent layer of that particular night was less than 1.8 km. The ongoing upgrade plans for a fivefold increase in the number of control elements and for the installation of a laser guide AO system are described.

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Section: Isoplanatic Anglesupporting

confidence: 83%

Performance of Subaru Cassegrain Adaptive Optics System

Takami

Takato

Hayano

et al. 2004

Publications of the Astronomical Society of Japan

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“…3. It can be seen how the total FWHM has a behavior consistent with what is observed for other AO PSFs (e.g., Flicker & Rigaut 2002).…”

Section: The Psf Model For Swansupporting

confidence: 82%

Accounting for the anisoplanatic point spread function in deep wide-field adaptive optics images

Cresci

Davies

Baker

et al. 2005

A&A

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Abstract. In this paper we present the approach we have used to determine and account for the anisoplanatic point spread function (PSF) in deep adaptive optics (AO) images for the Survey of a Wide Area with NACO (SWAN) at the ESO VLT. The survey comprises adaptive optics observations in the K s band totaling ∼30 arcmin 2 , assembled from 42 discrete fields centered on different bright stars suitable for AO guiding. We develop a parametric model of the PSF variations across the field of view in order to build an accurate model PSF for every galaxy detected in each of the fields. We show that this approach is particularly convenient, as it uses only easily available data and makes no uncertain assumptions about the stability of the isoplanatic angle during any given night. The model was tested using simulated galaxy profiles to check its performance in terms of recovering the correct morphological parameters; we find that the results are reliable up to K s ∼ 20.5 (K AB ∼ 22.3) in a typical SWAN field. Finally, the model obtained was used to derive the first results from five SWAN fields, and to obtain the AO morphology of 55 galaxies brighter than K s = 20. These preliminary results demonstrate the unique power of AO observations to derive the details of faint galaxy morphologies and to study galaxy evolution.

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“…Ref [15]. reports only a 7.2% underestimate of the effective turbulence vertical range by this 5/3 model.…”

mentioning

confidence: 79%

Evaluation of the on-sky performance of Altair

Stoesz

Véran

Rigaut

et al. 2004

Advancements in Adaptive Optics

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In this paper we evaluate the on-sky performance of Altair, the facility adaptive optics instrument at the Gemini North telescope. We describe the method for doing this on-sky evaluation, which includes: 1) the choice of suitable stellar fields for PSF observations that must cover a range of guide star magnitudes and angular separations from the guide star; 2) the observation strategy and data reduction pipeline; and 3) the PSF database from which the performance results are queried. The database stores observatory system parameters and performance observations such as FWHM, Strehl, encircled energy, wave front sensor flux, as well as coherence length (r o ) and outer scale (L o ) of the turbulence measured in closed loop and therefore coincident with the focal plane observations of the telescope. From the database we derive 20 to 24% Noll efficiency of the system and an estimated distribution of effective turbulence height above the summit to be 3.3 ± 0.6km. The performance evaluation strategy used on Altair is quite general and could be used for other adaptive optics systems.

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Hokupa`a Anisoplanatism and Mauna Kea Turbulence Characterization

Cited by 10 publications

References 15 publications

Performance of Subaru Cassegrain Adaptive Optics System

Performance of Subaru Cassegrain Adaptive Optics System

Accounting for the anisoplanatic point spread function in deep wide-field adaptive optics images

Evaluation of the on-sky performance of Altair

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