  The application of sodium laser guide star is the key difference between
modern adaptive optics system and traditional adaptive optics system.
Especially in system like multi-conjugate adaptive optics, sodium laser guide
star asterism which is formed by several laser guide stars in certain pattern
is required to probe more atmospheric turbulence in different directions. To
achieve this, a sodium laser guide star asterism launching platform is
required. In this paper, we will introduce the sodium laser guide star asterism
launching platform built and tested on the 1.8m telescope of the Gaomeigu
Observatory. The platform has two functions: one is to compare the performance
of sodium laser guide stars generated by different lasers at the same place;
the other is to generate sodium laser guide star asterism with adjustable
shape. The field test results at the beginning of 2021 verify the important
role of the platform, which is also the first time to realize sodium laser
guide star asterism in China.
