A radial shear interferometer for studying the shape of the wave front and aberrations of the optical system of the Luch setup were designed and created. To improve the interferometric pattern, the interferometer was simulated numerically by using the Fresnel software package. The parameters of the interferometer were optimized. The interferometer allows one to record interferograms of pulsed radiation at the first and second harmonics of a neodymium laser, as well as of continuous IR radiation with a short coherence length. A new method was developed for recovering the wave front by using the WinFringe software for interferograms with a reference front. Aberrations introduced by different parts and the entire optical system of the setup were measured. The wave fronts of the first and second harmonics obtained in full-scale experiments are presented. The experimental results agree with the radiation divergence measured by other methods.