Merge pull request #229 from shanosborne/distortion

Shift distorted PSFs back to correct detector position

webbpsf/distortion.py

@@ -1,14 +1,12 @@
-import copy
-
 import astropy.convolution
 import astropy.io.fits as fits
+import copy
 import numpy as np
+import poppy
 import pysiaf
 from scipy.interpolate import griddata
 from scipy.ndimage.interpolation import rotate
 
-import poppy
-
 
 def _get_default_siaf(instrument, aper_name):
     """ Store the default SIAF values for distortion and rotation """
@@ -98,6 +96,10 @@ def apply_distortion(hdulist_or_filename=None, fill_value=0):
     # Going from Idl to Sci this way allows us to add in the distortion
     xsci, ysci = aper.idl_to_sci(xidl, yidl)
 
+    # 6) Shift the sci indices so they match the PSF's position again (moved slightly off from pysiaf calculation)
+    xsci += xpix_center - np.median(xsci)
+    ysci += ypix_center - np.median(ysci)
+
     # ###############################################
     # Create an array of indices (in pixels) that the final data will be interpolated on to
     # 1) Set up blank indices (in pixels)