Stereo-SCIDAR: Optical turbulence profiling with high sensitivity using a modified SCIDAR instrument

Abstract

The next generation of adaptive optics (AO) systems will require tomographic reconstruction techniques to map the optical refractive index fluctuations, generated by the atmospheric turbulence, along the line of sight to the astronomical target. These systems can be enhanced with data from an external atmospheric profiler. This is important for Extremely Large Telescope scale tomography. Here we propose a new instrument which utilises the generalised SCIntillation Detection And Ranging (SCIDAR) technique to allow high sensitivity vertical profiles of the atmospheric optical turbulence and wind velocity profile above astronomical observatories. The new approach, which we refer to as 'Stereo-SCIDAR', uses a stereoscopic system with the scintillation pattern from each star of a double-star target incident on a separate detector. Separating the pupil images for each star has several advantages including: increased magnitude difference tolerance for the target stars; negating the need for re-calibration due to the normalisation errors usually associated with SCIDAR; an increase of at least a factor of two in the signal-to-noise ratio of the cross-covariance function and hence the profile for equal magnitude target stars and up to a factor of 16 improvement for targets of 3 magnitudes difference; and easier real-time reconstruction of the wind-velocity profile. Theoretical response functions are calculated for the instrument, and the performance is investigated using a Monte-Carlo simulation. The technique is demonstrated using data recorded at the 2.5 m Nordic Optical Telescope and the 1.0 m Jacobus Kapteyn Telescope, both on La Palma.

11 pages, 11 figures, accepted by MNRAS 27/11/13

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Cited by in corpus (18)

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• Scintillation correction for astronomical photometry on large and extremely large telescopes with tomographic atmospheric reconstruction
• Turbulence velocity profiling for high sensitivity and vertical-resolution atmospheric characterization with Stereo-SCIDAR
• PSF--NET: A Non-parametric Point Spread Function Model for Ground Based Optical Telescopes
• A comparison of next-generation turbulence profiling instruments at Paranal
• The wind-driven halo in high-contrast images I: analysis from the focal plane images of SPHERE
• Optimizing the accuracy and efficiency of optical turbulence profiling using adaptive optics telemetry for extremely large telescopes
• Limitations imposed by optical turbulence profile structure and evolution on tomographic reconstruction for the ELT
• Near ground horizontal high resolution $C_n^2$ profiling from Shack-Hartmann slope and scintillation data
• Atmospheric Scintillation Noise in Ground-Based Exoplanet Photometry
• Simultaneous Generalized and Low-Layer SCIDAR turbulence profiles at San Pedro Mártir Observatory
• Representative optical turbulence profiles for ESO Paranal by hierarchical clustering
• A tomographic algorithm to determine tip-tilt information from laser guide stars
• William Herschel Telescope site characterization using the MOAO pathfinder CANARY on-sky data
• Optical Turbulence forecast: new perspectives