Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical turbulence characterization at the SAAO Sutherland site   We present results from the first year of a campaign to characterize and
monitor the optical turbulence profile at the SAAO Sutherland observing station
in South Africa. A MASS-DIMM (MultiAperture Scintillation Sensor - Differential
Image Motion Monitor) was commissioned in March 2010 to provide continuous
monitoring of the seeing conditions. Over the first month of the campaign, a
SLODAR (SLOpe Detection And Ranging) from Durham University was also installed
allowing an independent verification of the performance of the MASS-DIMM
device. After the first year of data collection, the overall median seeing
value is found to be 1.32" as measured at ground level. The ground layer which
includes all layers below 1 km accounts for 84% of the turbulence, while the
free atmosphere above 1 km accounts for 16% with a median value of 0.41". The
median isoplanatic angle value is 1.92", which is similar to other major
astronomical sites. The median coherence time, calculated from corrected MASS
measurements, is 2.85 ms. The seeing conditions at the site do show a strong
correlation with wind direction with bad seeing conditions being associated
with winds from the South-East.

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The categories of this paper are: stat
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: mtrl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: cs
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The categories of this paper are: physics
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga