[en] A wide-aperture magnetic pair spectrometer (MPS) used to obtain the spectral characteristics of radiation in planar and axial channeling of electrons of the Yerevan synchrotron extracted beam is described. The design and characteristics of the wide-aperture MPS consisting of the SP-57 magnet and multiwire proportional chambers located along the magnet poles are described. From 30 to 1000 MeV gamma quanta are registered at the magnet current of 50 and 150 A. The results of measurements carried out for axial channeling of 4.5 GeV electrons on a 1 mm thick diamond crystal are also presented. The emission spectrum obtained by means of the MPS is compared with that measured by a NaI(Tl) detector. 3 refs.; 9 figs