Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Introduction to pinhole astronomy   The observation of the Sun with a pinhole in order to check the first and the
second Kepler's law has been realized for high school students. The settling of
the experiment in order to minimize the errors of measure has permitted to
verify the Rayleigh formula for obtaining sharpest images given the diameter of
the pinhole.

9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
21
The categories of this paper are: adap-org