diff --git a/heracles/catalog/filters.py b/heracles/catalog/filters.py
index c1e6dbb..cddafac 100644
--- a/heracles/catalog/filters.py
+++ b/heracles/catalog/filters.py
@@ -61,9 +61,9 @@ def __call__(self, page):
 
 class FootprintFilter:
     """Filter a catalogue using a footprint map.
-        This rempoves the pixels that are not in the footprint map.
-        Moreover, it removes the pixels which have NaN values in the
-        longitude and latitude columns."""
+    This rempoves the pixels that are not in the footprint map.
+    Moreover, it removes the pixels which have NaN values in the
+    longitude and latitude columns."""
 
     def __init__(self, footprint, lon, lat):
         """Filter using the given footprint map and position columns."""