Resolution No.5 (1963): R-index

The IAGA notes that for some observatories in geomagnetic latitudes higher than about 65 degrees, an additional index will be available, namely an hourly R-index, indicating the absolute hourly range in each horizontal component expressed in tens of gamma. A circular concerning these data will be distributed soon to observatories wishing to take part in such a tentative scheme which is to start on January 1st, 1964.