Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: PMAS: The Potsdam Multi Aperture Spectrophotometer. II. The Wide
  Integral Field Unit PPak   PPak is a new fiber-based Integral Field Unit (IFU), developed at the
Astrophysical Institute Potsdam, implemented as a module into the existing PMAS
spectrograph. The purpose of PPak is to provide both an extended field-of-view
with a large light collecting power for each spatial element, as well as an
adequate spectral resolution. The PPak system consists of a fiber bundle with
331 object, 36 sky and 15 calibration fibers. The object and sky fibers collect
the light from the focal plane behind a focal reducer lens. The object fibers
of PPak, each 2.7 arcseconds in diameter, provide a contiguous hexagonal
field-of-view of 74 times 64 arcseconds on the sky, with a filling factor of
60%. The operational wavelength range is from 400 to 900nm. The PPak-IFU,
together with the PMAS spectrograph, are intended for the study of extended,
low surface brightness objects, offering an optimization of total
light-collecting power and spectral resolution. This paper describes the
instrument design, the assembly, integration and tests, the commissioning and
operational procedures, and presents the measured performance at the telescope.

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The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
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The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg