  In this note we derive the descriptions of the system of Euler-Poisson
equations which governs the hydrodynamic evolution of gaseous stars in various
co-ordinate systems. This note does not contain essentially new results for
astrophysicists, but mathematically rigorous derivations cannot be found in the
literatures written by physicists so that it will be useful to prepare details
of rather stupidly honest derivations of the equations in various flames when
we are going to push forward the mathematical research of the problem.
