'sat_eph' now assumes reasonable default values for start time (now),…

… number of ephemeris steps (20), and step size (one hour). It also defaults to rounding to the nearest ephemeris step size, and is slightly better about outputting an error message when errors happen.

sat_eph.c

@@ -320,6 +320,8 @@ int generate_artsat_ephems( const char *path_to_tles, const ephem_t *e)
    int is_in_range = 0, id_matches = 1, start_line = 0;
 
    snprintf( buff, sizeof( buff), "%s/%s", path_to_tles, tle_list_filename);
+   if( verbose > 1)
+      printf( "Opening '%s'\n", buff);
    ifile = fopen( buff, "rb");
    if( !ifile)
       {
@@ -469,16 +471,19 @@ int dummy_main( const int argc, const char **argv)
 {
    int i;
    ephem_t e;
-   bool round_to_nearest_step = false;
+   bool round_to_nearest_step = true;
    const char *mpc_code = "500";
    const char *override_tle_filename = NULL;
 
-   if( argc < 3)
+   if( argc < 2)
       {
       error_help( );
       return( 0);
       }
    memset( &e, 0, sizeof( ephem_t));
+   e.jd_start = current_jd( );
+   e.n_steps = 20;
+   e.step_size = 1. / 24.;
    for( i = 1; i < argc; i++)
       if( argv[i][0] == '-' && argv[i][1])
          {
@@ -496,13 +501,8 @@ int dummy_main( const int argc, const char **argv)
                override_tle_filename = arg;
                break;
             case 't':
-               {
-               const double jan_1970 = 2440587.5;
-               const double curr_jd = jan_1970 + (double)time( NULL) / (double)seconds_per_day;
-
-               e.jd_start = get_time_from_string( curr_jd, arg, FULL_CTIME_YMD, NULL);
+               e.jd_start = get_time_from_string( e.jd_start, arg, FULL_CTIME_YMD, NULL);
                break;
-               }
             case 'n':
                e.n_steps = atoi( arg);
                break;