DISPLACEMENTS OF THE RADIANT POINT DURING THE AURORAL DISTURBANCE OF SEPTEMBER 22, 1957

Abstract

Three detailed photographs of the corona on a well-defined star field taken during the display of September 22, 1957, render possible determination of the position of the radiant point and measurement of its displacements. The photographs cover an interval of 21 minutes and the measured displacement, assumed to be continuous, divided by this interval gives an average rate of motion of about 12 minutes of arc per minute of time. The variation of the magnetic elements in the same interval is such as to indicate displacements of the magnetic zenith which, viewed from ground level, appear unrelated to the displacements of the radiant point.