Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Seeing, Wind and Outer Scale Effects on Image Quality at the Magellan
  Telescopes   We present an analysis of the science image quality obtained on the twin 6.5
metre Magellan telescopes over a 1.5 year period, using images of ~10^5 stars.
We find that the telescopes generally obtain significantly better image quality
than the DIMM-measured seeing. This is qualitatively consistent with
expectations for large telescopes, where the wavefront outer scale of the
turbulence spectrum plays a significant role. However, the dominant effect is
found to be wind speed with Magellan outperforming the DIMMs most markedly when
the wind is strongest. Excluding data taken during strong wind conditions (>10
m/s), we find that the Magellan telescopes still significantly outperform the
DIMM seeing, and we estimate the site to have L_0 ~ 25 m on average. We also
report on the first detection of a negative bias in DIMM data. This is found to
occur, as predicted, when the DIMM is affected by certain optical aberrations
and the turbulence profile is dominated by the upper layers of the atmosphere.

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The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph