diff --git a/CAL/CalibrationCommon/lib/datacontainers/holography_measurementset.py b/CAL/CalibrationCommon/lib/datacontainers/holography_measurementset.py
index 7446bf3c9c69a9e515a1f3e37b2e6334b66f3764..0c136e995909b25a5dcf2951744009332d85fa6d 100644
--- a/CAL/CalibrationCommon/lib/datacontainers/holography_measurementset.py
+++ b/CAL/CalibrationCommon/lib/datacontainers/holography_measurementset.py
@@ -215,7 +215,7 @@ class HolographyMeasurementSet(object):
         if not HolographyMeasurementSet.is_a_valid_ms_name(ms_name):
             raise ValueError('The measurement set %s has not a valid name' % ms_name,)
         match = re.match(HolographyMeasurementSet.ms_name_pattern, ms_name)
-        return (int(match.group('sas_id')), int(match.group('sub_band_id')))
+        return (str(match.group('sas_id')), int(match.group('sub_band_id')))
 
 
     @staticmethod
diff --git a/CAL/CalibrationCommon/lib/datacontainers/holography_observation.py b/CAL/CalibrationCommon/lib/datacontainers/holography_observation.py
index 71aeef558c68f2da6af93b644b67a7532e278e1a..3af56f86790a199913cfa149d9a522a537aeecef 100644
--- a/CAL/CalibrationCommon/lib/datacontainers/holography_observation.py
+++ b/CAL/CalibrationCommon/lib/datacontainers/holography_observation.py
@@ -99,7 +99,7 @@ class HolographyObservation():
         for root, dirnames, filenames in os.walk(path):
             match = re.match(ms_dirs_path_pattern, root)
             if match:
-                sas_id = int(match.group('sas_id'))
+                sas_id = match.group('sas_id')
 
                 ms_indexed_per_beamlet_number = HolographyObservation. \
                     create_ms_dict_from_ms_name_list_and_path(dirnames, root)