Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new approach for the heliometric optics   The heliometer of Fraunhofer in Koenigsberg (1824) is a refractor in which
the lens is split into two halves to which is applied a linear displacement
along the cut. Later in 1890s a variation of the heliometer has been realized
in Goettingen using a beam splitting wedge: these methods were both subjected
to chromatic and refractive aberrations; the second configuration being much
less affected by thermal fluctuations. The mirrored version of the heliometer
conceived at the Observatorio Nacional of Rio de Janeiro overcome these
problems: the two halves of the vitrified ceramic mirror split at a fixed
heliometric angle produce the two images of the Sun exempt of chromatisms and
distortions. The heliometer of Rio is a telescope which can rotate around its
axis, to measure the solar diameter at all heliolatitudes. A further
development of that heliometer, now under construction, is the annular
heliometer, in which the mirrors are concentric, with symmetrical Point Spread
Functions. Moreover the location of the Observatory of Rio de Janeiro allows
zenithal observations, with no atmospheric refraction at all heliolatitudes, in
December and January.

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The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys