We present the results of computationsof thetrajectories(the asymptotic latitude and asymptotic longitude) and themagnetic cutoffrigidity ofgalactic cosmic ray(GCR)particlesfor the airport Deblin, Poland (geographical latitude 51°33′32′′N, geographical longitude21°50′53′′E)basedon the numerical integration of equations of motion of charged particles of cosmic raysin the Earth's magnetic field. The set of allowed trajectories at a given site on the surface of the earth is called the asymptotic cone of acceptance.The initial distance from the center of theEarth was taken to be 20 km above the Earth's surface. At about this altitude, most cosmic rays undergo nuclear collisions.