Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Design Differences between the Pan-STARRS PS1 and PS2 Telescopes   The PS2 telescope is the second in an array of wide-field telescopes that is
being built for the Panoramic-Survey Telescope and Rapid Response System
(Pan-STARRS) on Haleakala. The PS2 design has evolved incrementally based on
lessons learned from PS1, but these changes should result in significant
improvements in image quality, tracking performance in windy conditions, and
reductions in scattered light. The optics for this telescope are finished save
for their coatings and the fabrication for the telescope structure itself is
well on the way towards completion and installation on-site late this year
(2012). The most significant differences between the two telescopes include the
following: secondary mirror support changes, improvements in the optical
polishing, changes in the optical coatings to improve throughput and decrease
ghosting, removal of heat sources inside the mirror cell, expansion of the
primary mirror figure control system, changes in the baffle designs, and an
improved cable wrap design. This paper gives a description of each of these
design changes and discusses the motivations for making them.

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The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
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The categories of this paper are: nlin
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The categories of this paper are: math
37
The categories of this paper are: supr-con
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The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg