Project for bidimensional spectroscopy of solar chromospheric active regions with the universal birefringent filter

In the present work, the universal birefringent filter of the Sacramento Peak Observatory, which can operate effectively over a wide range of wavelengths and whose bandwidth is comparable to that of the instrumental profile of a low-resolution spectrograph, was used to obtain a sequence of monochromatic images of a solar active region at selected points along the profile of a strong Fraunhofer line, i.e., at different wavelengths from the line center. A series of observations is proposed to cover exhaustively a wide range of depths in the solar atmosphere.