diff --git a/defdap/crystal.py b/defdap/crystal.py
index 7fe47d2..e6e4fa7 100755
--- a/defdap/crystal.py
+++ b/defdap/crystal.py
@@ -296,7 +296,7 @@ def __init__(self, slip_plane, slip_dir, crystal_structure, c_over_a=None):
 
         Parameters
         ----------
-        slip_plane: nunpy.ndarray
+        slip_plane: numpy.ndarray
             Slip plane.
         slip_dir: numpy.ndarray
             Slip direction.
diff --git a/docs/source/conf.py b/docs/source/conf.py
index a1cafa6..3d79157 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -79,6 +79,8 @@ def get_version():
 
 nbsphinx_allow_errors = True
 nbsphinx_execute = 'always'
+nbsphinx_kernel_name = 'python3'
+
 nbsphinx_prolog = """
 This page was built from the example_notebook Jupyter notebook available on `Github <https://github.com/MechMicroMan/DefDAP>`_