Astrophysical opacities and moment methods in the interpretation of spectral observation in atomic spectra

The calculation of astrophysical opacities involves an understanding of atomic and electronic processes. For the most part these processes are well known. While the fundamentals are well known the practical matter of obtaining cross sections and spectral information is a difficult and time-consuming task. The most important physical processes which need to be considered for opacity calculations are given. A table is also included so that the reader can see the types of mixtures used in astrophysical structural calculations. This particular one has been used for calculating the solar neutrino flux