... For high spectral resolution observations the devices permanently located at the N2 focus of the BTA are used (Klochkova, 1995, Panchuk, 1995). However for a number of tasks to be performed, it is needed to rule out the influence of the second and third mirrors, i.e. to realize the high spectral resolution ( ) directly at the prime focus. ... Examine the principal parameters of the PF echelle spectrometer, which is equivalent in spectral resolution to the CCD-equipped MSS (Panchuk, 1995). ...