Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two hundred years of galactic studies in Tartu Observatory   An overview is provided for 200 years of galactic studies at the Tartu
Observatory. Galactic studies have been one of the main topics of studies in
Tartu over the whole period of the history of the Observatory, starting from
F.G.W. Struve and J.H. M"adler, followed by Ernst "Opik and Grigori Kuzmin, and
continuing with the present generation of astronomers. Our goal was to
understand better the structure, origin and evolution of stars, galaxies and
the Universe.

31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con