diff --git a/sapphire/analysis/reconstructions.py b/sapphire/analysis/reconstructions.py
index f4525f97..d50813b0 100644
--- a/sapphire/analysis/reconstructions.py
+++ b/sapphire/analysis/reconstructions.py
@@ -98,7 +98,7 @@ def _reconstruct_direction(self, event, detector_ids=None):
         valid_ids = [id for id in range(4)
                      if event['t%d' % (id + 1)] not in ERR]
         if detector_ids is not None:
-           detector_ids = [d for d in detector_ids if d in valid_ids]
+            detector_ids = [d for d in detector_ids if d in valid_ids]
         else:
             detector_ids = valid_ids