NAME: geo2mag PURPOSE: Convert from geographic to geomagnetic coordinates CALLING SEQUENCE: geo2mag, time, data_in, data_out INPUT: time = an array [n] of double precision time in seconds from 1970-Jan-01/00:00:00.000 data_in = an array [n,3] of position data in km. in GEO coordinates or a tplot variable KEYWORD INPUTS: None OUTPUT: data_out = an array [n,3] of the input data in MAG coordinates EXAMPLE: IDL> geo2mag, data_in data_out NOTES: The algorithm and rotational matrices were developed by Pascal Saint-Hilaire (Saint-Hilaire@astro.phys.ethz.ch), May 2002 MODIFICATION HISTORY: