Geomagnetic Indices Bulletin is a prompt monthly information publication that is distributed within two weeks after final geomagnetic indices are received for the observational month. For each month this 2-page circular tabulates the three hour Kp indices, daily Ap index, Cp index, An,As,Am index and provisional aa indices. Contact the Data Center for information on how to subscribe to this bulletin or go directly to the NOAA Online Store for online subscription purchase .