be assumed to depend linearly on the count rate of gamma-quanta detected by NEGA- 1. In this case, the initial count rates in the analyzed time series $N_x$ can be represented as a superposition of the X-ray count rate proper $N_{x}^*$, which characterizes the photon flux under study, and the additional count rate $\alpha N_{\gamma}$ attributable to the local gamma- emission: $$N_{x} = N_{x}^{*} + \alpha N_{\gamma}.$$ The linear regression coefficients $\alpha$ were determined over the entire observation interval when there were no bright sources of hard emission within the PX-2 field of view. The $\alpha$ coefficient values were used to obtain the time series of count rates $N_{x}^{*} = N_{x} - \alpha 
N_{\gamma}$ for the subsequent analysis. The suppression of background variations with the use of readings in the 150-500 keV gamma-quanta channel yielded the most significant result. After applying the regression procedure, the residual variations in the X-ray channels attributable to the latitudinal variations accounted for no more than $\sim 3\%$ of the corresponding means, which is several times less than the expected amplitude of the variations attributable to the emission from the most intense Galactic source.

In the search for periodicities, the time series of count rates 