diff --git a/ChangeLog b/ChangeLog
index 8dd8a12..1c64727 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,8 +1,10 @@
-2018-01-12
+2018-01-22
 
         * Version 1.5.0 released
         ========================
 
+        Change DATE_OBS, DATE_END, TIME_OBS and TIME_END FITS keywords into DATA-OBS,
+          DATE-END, TIME-OBS and TIME-END
         Add CUSTOM background method to csphagen script (#2284)
         Add csresspec script (#2289)
         Add ctools::time_reference constant and remove ctools::time_reference() method (#2295)
diff --git a/NEWS b/NEWS
index 5f1f60d..85d9a7a 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,4 @@
-12 January 2018
+22 January 2018
 
 
 Introduction
@@ -136,6 +136,9 @@ Add "statistic" parameter to allow setting of optimizer statistic (#2237).
 
 support - Support classes
 -------------------------
+Change DATE_OBS, DATE_END, TIME_OBS and TIME_END FITS keywords into DATA-OBS,
+DATE-END, TIME-OBS and TIME-END.
+
 Add ctobservation.obs() method to set an observation container.
 
 
diff --git a/doc/source/admin/release_history/1.5.rst b/doc/source/admin/release_history/1.5.rst
index 5d6249e..7eebbd6 100644
--- a/doc/source/admin/release_history/1.5.rst
+++ b/doc/source/admin/release_history/1.5.rst
@@ -17,6 +17,8 @@ In particular, this release provides:
 Bug fixes
 ---------
 
+* Change ``DATE_OBS``, ``DATE_END``, ``TIME_OBS`` and ``TIME_END`` FITS keywords
+  into ``DATA-OBS``, ``DATE-END``, ``TIME-OBS`` and ``TIME-END``
 * [`2287 <https://cta-redmine.irap.omp.eu/issues/2287>`_] -
   Correctly strip .gz suffix from output filenames
 * [`2262 <https://cta-redmine.irap.omp.eu/issues/2262>`_] -
diff --git a/src/support/ctobservation.cpp b/src/support/ctobservation.cpp
index d65304c..d15ee6f 100644
--- a/src/support/ctobservation.cpp
+++ b/src/support/ctobservation.cpp
@@ -1,7 +1,7 @@
 /***************************************************************************
  *             ctobservation - Base class for observation tools            *
  * ----------------------------------------------------------------------- *
- *  copyright (C) 2016-2017 by Juergen Knoedlseder                         *
+ *  copyright (C) 2016-2018 by Juergen Knoedlseder                         *
  * ----------------------------------------------------------------------- *
  *                                                                         *
  *  This program is free software: you can redistribute it and/or modify   *
@@ -349,10 +349,10 @@ void ctobservation::write_ogip_keywords(GFitsHDU* hdu) const
         hdu->card("TELESCOP", m_ogip_telescope, "Telescope");
 
         // Set observation time information
-        hdu->card("DATE_OBS", date_obs,        "Observation start date");
-        hdu->card("TIME_OBS", time_obs,        "Observation start time");
-        hdu->card("DATE_END", date_end,        "Observation end date");
-        hdu->card("TIME_END", time_end,        "Observation end time");
+        hdu->card("DATE-OBS", date_obs,        "Observation start date");
+        hdu->card("TIME-OBS", time_obs,        "Observation start time");
+        hdu->card("DATE-END", date_end,        "Observation end date");
+        hdu->card("TIME-END", time_end,        "Observation end time");
         hdu->card("TELAPSE",  m_ogip_telapse,  "[s] Elapsed time");
         hdu->card("ONTIME",   m_ogip_ontime,   "[s] Total good time including deadtime");
         hdu->card("LIVETIME", m_ogip_livetime, "[s] Total livetime");