diff --git a/star_chart_spherical_projection/declination_r_axis.py b/star_chart_spherical_projection/declination_r_axis.py
index 9bd75fc..0aac0e9 100644
--- a/star_chart_spherical_projection/declination_r_axis.py
+++ b/star_chart_spherical_projection/declination_r_axis.py
@@ -29,7 +29,7 @@ def _calculate_ruler(declination_min, declination_max, increment, pole):
     # define the length of each segment in ruler when radius = 1
 
     x_angle_of_declination = np.arange(-90, 90+1,increment) # declination max range from -90 to 90
-    y_lengthSegments = []
+    y_length_segments = []
 
     declination_angles_ruler = np.arange(-90, 90+1, increment) # declination max range from -90 to 90
 
@@ -41,12 +41,12 @@ def _calculate_ruler(declination_min, declination_max, increment, pole):
     for n_angle in declination_angles_ruler:
         if pole == "North":
             ruler_position = _calculate_length(n_angle, radius_of_circle, "North")
-            y_lengthSegments.append(ruler_position)
+            y_length_segments.append(ruler_position)
             if n_angle >= declination_min and n_angle <= declination_max: # North
                 ruler_position_dict[n_angle] = round(ruler_position, 4)
         if pole == "South":
             ruler_position = _calculate_length(n_angle, radius_of_circle, "South")
-            y_lengthSegments.append(ruler_position)
+            y_length_segments.append(ruler_position)
             if n_angle <= declination_min and n_angle >= declination_max: # South
                 ruler_position_dict[n_angle] = round(ruler_position, 4)