Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evaluation of Optical Magnitude of Deep Space Spacecraft   Optical-electric technology can measure the tangential position and velocity
of spacecraft. To know the feasibility of the use of optical-electric
technology, it is necessary to estimate the magnitude of spacecraft first.
Since the spacecrafts are non-self-illumination objects, the estimation
formulas of the optical magnitude of spacecraft is constructed according to the
radiation theory and the extra-atmospheric radiant emittance of the Sun in the
visible light wave band. Taking Chang'e-1 as an example, the magnitude of it in
different situations is calculated.

30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio