diff --git a/poppy/optics.py b/poppy/optics.py
index 66ffd009..06771549 100644
--- a/poppy/optics.py
+++ b/poppy/optics.py
@@ -566,7 +566,7 @@ def get_transmission(self, wave):
             else:
                 raise NotImplemented("No defined NIRCam wedge BLC mask for that wavelength?  ")
 
-            sigmas = scipy.poly1d(polyfitcoeffs)(scalefact)
+            sigmas = numpy.poly1d(polyfitcoeffs)(scalefact)
 
             sigmar = sigmas * np.abs(y)
             sigmar.clip(np.finfo(sigmar.dtype).tiny, out=sigmar)  # avoid divide by zero -> NaNs