diff --git a/setup.cfg b/setup.cfg
index 75ed4d1..85e51a9 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -32,7 +32,8 @@ test_require =
     tox:tox
 
 [options.extras_require]
-relalt =
+optional =
+    pandas
     cf-units
     xarray
     netcdf4
diff --git a/src/pyaro/timeseries/Filter.py b/src/pyaro/timeseries/Filter.py
index 963c5df..8e8ac8e 100644
--- a/src/pyaro/timeseries/Filter.py
+++ b/src/pyaro/timeseries/Filter.py
@@ -895,7 +895,7 @@ def __init__(self, topo_file: str | None = None, topo_var: str = "topography", r
         Note:
         -----
         This filter requires additional dependencies (xarray, netcdf4, cf-units) to function. These can be installed
-        with `pip install .[relalt] 
+        with `pip install .[optional] 
         """
         if "cf_units" not in sys.modules:
             logger.warning("relaltitude filter is missing required dependency 'cf-units'. Please install to use this filter.")