A calculation of the magnetic field in the solar corona during the total solar eclipse on 1 August 2008 was performed using a PFSS model in classic and radial approach. The potential model for calculation of the magnetic field in the solar corona on the basis of field expansion using spherical functions and the procedure for visualization of magnetic lines of force are shortly described. Some observations of photospheric magnetic fields made at the WSO were used to find harmonic coefficients. Maps of coronal magnetic field at the source sur face were constructed and configurations of magnetic field lines in the solar corona were drawn. The obtained results were compared with the coronal structure observed during the eclipse.