Analysis of anisotropy of cosmic rays with the energy of about 1017 eV by Yakutsk EAS array data

A harmonic analysis of the directions of arrival of cosmic-ray particles with an energy of about 1017 eV in the vicinity of the registration threshold of the Yakutsk extensive air showers (EAS) array is given. A method for determining the contribution of inhomogeneous observation conditions and seasonal variations of the frequency of extensive air showers to the observed anisotropy is suggested. Taking into account these factors results in a considerable decrease of the amplitude characterizing the degree of anisotropy of cosmic-ray primaries. The amplitude of the first harmonic with respect to the right ascension is (0.45 ± 0.55)%, which shows that no probably significant anisotropy of the primary radiation is observed at 1017 eV.