prompt> gtephem strict=yes This is gtephem version v8r2 Pulsar ephemerides database file name[] master_pulsardb_v3.fits Pulsar name[ANY] PSR B0540-69 Reference time at which to find/compute ephemeris[0.] 54369.3 Time format for the reference time of this ephemeris computation (MJD|ISO|GLAST) [MJD] MJD Time system for the reference time of this ephemeris computation (TAI|TDB|TT|UTC)) [TDB] TDB gtephem: No spin ephemeris was found in database: StrictEphChooser::choose: Could not find a spin ephemeris for 25920 seconds after 54369.0 MJD (TDB) prompt>