# periodically check for ephemeris
    while ( $self{'stat'} ne 'done' ) {

        # Check for new ephemeris
        $self{'miner'}{$t}{'expi'} = time() + $cnf{'period'};
        $self{'miner'}{$t}{'data'} = retrieve_data(@p);
        select undef, undef, undef, $cnf{'period'};
    }