diff --git a/Cargo.toml b/Cargo.toml
index 5af6460..885501b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,7 +32,7 @@ version = "0.22"
 features = ["extension-module"]
 
 [dependencies.ndarray]
-version = "0.15.6"
+version = "0.16"
 default-features = false # do not include the default features, and optionally
                          # cherry-pick individual features
 features = ["rayon"]
diff --git a/src/lib.rs b/src/lib.rs
index 81241ea..c4912e4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,12 +1,3 @@
-extern crate healpix;
-
-extern crate rayon;
-
-extern crate ndarray;
-
-extern crate numpy;
-extern crate pyo3;
-
 use ndarray::{Array1, Zip};
 use numpy::{IntoPyArray, PyArray1, PyArrayDyn, PyArrayMethods, PyReadonlyArrayDyn};
 use pyo3::{