Self-adjusting data acquisition system for Low Layer SCIDAR

Authors

  • J. L. Avilés,

    Corresponding author
    1. Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro 1, Tonantzintla, Puebla 72840, Mexico
    2. Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70–264, Cd. Universitaria 04510, México D.F., Mexico
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  • R. Avila,

    1. Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apartado Postal 3-72, Morelia Michoacán, C.P. 58089, Mexico
    2. Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Santiago de Querétaro, Qro. 76000, Mexico
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  • T. Butterley,

    1. Department of Physics, Durham University, South Road, Durham DH1 3LE
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  • R. Wilson,

    1. Department of Physics, Durham University, South Road, Durham DH1 3LE
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  • M. Chun,

    1. Institute for Astronomy, University of Hawaii, 640 North A’ohoku Place, 209 Hilo, Hawaii 96720-2700, USA
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  • E. Carrasco,

    1. Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro 1, Tonantzintla, Puebla 72840, Mexico
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  • A. Farah,

    1. Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70–264, Cd. Universitaria 04510, México D.F., Mexico
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  • S. Cuevas

    1. Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 70–264, Cd. Universitaria 04510, México D.F., Mexico
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E-mail: aviles@inaoep.mx

ABSTRACT

We present a real-time, fully automated method to remove instrumental signatures from stellar scintillation images. The method was developed in connection with the Low Layer SCIDAR (Scintillation Detection and Ranging) (LOLAS), an instrument dedicated to the measurement of atmospheric optical-turbulence profiles, inline image, in the first kilometre of altitude, with high altitude-resolution. By examining the scintillation images and their correlation maps we evaluate, and then correct, image deficiencies typical of a portable telescope, such as defocus, image movement, field rotation and tracking errors, prior to processing according to the SCIDAR technique. In addition, detector spreading noise is corrected for, and flux variations caused by clouds or fog are monitored. The efficiency of the methods is demonstrated by comparing double-star scintillation autocorrelations obtained with and without the use of the self-adjusting procedures. Applying those stabilization methods, LOLAS was successfully exploited to characterize the inline image vertical profiles along the lower layer on top of Mauna Kea Observatory.

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