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Optical sparse telescope arrays and scintillation noise

Hartley, Kathryn E; Farley, Oliver J D; Townson, Matthew J; Osborn, James; Wilson, Richard W

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Kathryn E Hartley

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Ollie Farley
Post Doctoral Research Associate


Fresnel propagation of starlight after it passes through high altitude turbulence in the Earth’s atmosphere results in random fluctuations of the intensity at ground level, known as scintillation. This effect adds random noise to photometric measurements with ground-based optical telescopes. Spatial correlation of the intensity fluctuations means that the fractional photometric noise due to scintillation may be substantially smaller for a sparse array of small aperture telescopes than for a single large aperture of the same total area. Assuming that the photometric noise for each telescope is independent, averaging the light curves measured by N telescopes reduces the noise by a factor of N−−√
⁠. For example, for bright stars, the signal-to-noise ratio of a 2.54 m telescope can be achieved for an array of thirty 20 cm telescopes if the scintillation noise measured for each telescope is uncorrelated. In this paper, we present results from simulation and from observations at the Isaac Newton Telescope. These explore the impact that several parameters have on the measured correlation of the scintillation noise between neighbouring telescopes. We show that there is significant correlation between neighbouring telescopes with separations parallel to the wind direction of the dominant high altitude turbulent layer. We find that the telescopes in an array should be separated by at least twice their aperture diameter so that there is negligible correlation of the photometric noise. We discuss additional benefits of using sparse telescope arrays, including reduced cost and increased field of view.


Hartley, K. E., Farley, O. J. D., Townson, M. J., Osborn, J., & Wilson, R. W. (2023). Optical sparse telescope arrays and scintillation noise. Monthly Notices of the Royal Astronomical Society, 526(1), 1235-1245.

Journal Article Type Article
Acceptance Date Sep 13, 2023
Online Publication Date Sep 18, 2023
Publication Date 2023-11
Deposit Date Nov 2, 2023
Publicly Available Date Nov 2, 2023
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 526
Issue 1
Pages 1235-1245
Keywords Space and Planetary Science; Astronomy and Astrophysics
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Copyright Statement
The Author(s) 2023. Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium,
provided the original work is properly cited.

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