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

Shepherd, H.; Osborn, J.; Wilson, R.W.; Butterley, T.; Avila, R.; Dhillon, V.; Morris, T.J.

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H. Shepherd

T. Butterley

R. Avila

V. Dhillon


The next generation of adaptive optics 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 utilizes the generalized 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 normalization errors usually associated with SCIDAR; an increase of at least a factor of 2 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 mag 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.


Shepherd, H., Osborn, J., Wilson, R., Butterley, T., Avila, R., Dhillon, V., & Morris, T. (2014). Stereo-SCIDAR: optical turbulence profiling with high sensitivity using a modified SCIDAR instrument. Monthly Notices of the Royal Astronomical Society, 437(4), 3568-3577.

Journal Article Type Article
Acceptance Date Nov 5, 2013
Online Publication Date Nov 28, 2013
Publication Date Feb 1, 2014
Deposit Date Nov 24, 2014
Publicly Available Date Apr 15, 2015
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 437
Issue 4
Pages 3568-3577
Keywords Atmospheric effects, Instrumentation: adaptive optics, Site testing.


Published Journal Article (3.3 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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