diff --git a/src/ctselect/ctselect.cpp b/src/ctselect/ctselect.cpp
index 4b19f34..f646b76 100644
--- a/src/ctselect/ctselect.cpp
+++ b/src/ctselect/ctselect.cpp
@@ -548,6 +548,7 @@ void ctselect::select_events(GCTAObservation* obs, const std::string& filename)
         //double tmin = gti.tstart().convert(m_cta_ref);
         //double tmax = gti.tstop().convert(m_cta_ref);
         GTimeReference ref = gti.tstart().reference() ;
+        printf("ctselect::select_events() NKH convert timref %f\n", ref.mjdref() ) ;
         double tmin = gti.tstart().convert( ref ) ;
         double tmax = gti.tstop( ).convert( ref ) ;