Neil Clifford has kindly added the file "n21_desc" to his subdirectory that contains Ted Molczan's elsets. It describes the format used the elset files. Thanks Neil ftp://ftp.physics.ox.ac.uk/pub/sat/mirrors/molc/ Jeff Hunt<jhunt@eagle1.eaglenet.com> A summary of links for sat tracking programs and elsets can be found at: http://www.physics.ox.ac.uk/sat/tletools.htm