Aberrations of spectrographs with the correction of the Schmidt camera effected in the collimator

Of the different ways to introduce the Schmidt correction of the camera in a spectrograph, the case was studies in which it is effected in the collimator. Equations which describe the form of the wavefront at one side of the grating as function of the form at the other side were found. The sixth order terms in the correction to compensate for the deformation of the wave front in the path from the collimator to the grating and to the mirror were also found. The aberrations for a correction which is symmetrical around* the collimator axis were calculated. The limit of camera aperture for which this aberrations are tolerable is between F/D = 4 and F/D = 3 according to the size and number of lines of the grating. Este trabajo será publicado en Óptica Acta.Asociación Argentina de Astronomí