After the course the student knows basic radiation terms. Student can write the radiative transfer equation and solve it using different approximations. Students can compute the ionization state of matter. Student knows basic methods to compute stellar atmospheres, can compute emission and absorption coefficients and use them in the radiative transfer equation. Student is able to explain what is the Rosseland mean opacity and why it is important. Student is able to explain the meaning of Einstein coefficients and how using them to explain the existence of lasers and masers. Student is aware of the basic mechanisms that widen spectral lines, knows how to use the curve of growth to compute the abundance of elements. Student is able to explain the difference between degenerate and ideal gas. Student is capable of writing the main equation describing stellar structure and knows the main nuclear reactions.