Merge pull request #509 from kammerje/develop

Updating bar mask offsets directly from pySIAF

webbpsf/optics.py

@@ -19,6 +19,8 @@
 
 _log = logging.getLogger('webbpsf')
 
+import pysiaf
+
 
 #######  Classes for modeling aspects of JWST's segmented active primary #####
 
@@ -706,31 +708,6 @@ class NIRCam_BandLimitedCoron(poppy.BandLimitedCoron):
     allowable_kinds = ['nircamcircular', 'nircamwedge']
     """ Allowable types of BLC supported by this class"""
 
-    # Offsets along the bar occulters are based on
-    # outputs from John Stansberry's filt_baroffset.pro
-    # See https://github.com/mperrin/webbpsf/issues/63
-    offset_swb = {"F182M": -1.856,
-                  "F187N": -1.571,
-                  "F210M": -0.071,
-                  "F212N": 0.143,
-                  "F200W": 0.232,
-                  'narrow': -8.00}
-    """ Offsets per filter along SWB occulter for module A, in arcsec"""
-
-    offset_lwb = {"F250M": 6.846,
-                  "F300M": 5.249,
-                  "F277W": 5.078,
-                  "F335M": 4.075,
-                  "F360M": 3.195,
-                  "F356W": 2.455,
-                  "F410M": 1.663,
-                  "F430M": 1.043,
-                  "F460M": -0.098,
-                  "F480M": -0.619,
-                  "F444W": -0.768,
-                  'narrow': 8.0}
-    """ Offsets per filter along LWB occulter for module A, in arcsec"""
-
     def __init__(self, name="unnamed BLC", kind='nircamcircular', module='A', nd_squares=True,
                  bar_offset=None, auto_offset=None, **kwargs):
         super(NIRCam_BandLimitedCoron, self).__init__(name=name, kind=kind, **kwargs)
@@ -757,6 +734,13 @@ def __init__(self, name="unnamed BLC", kind='nircamcircular', module='A', nd_squ
         else:
             raise NotImplementedError("invalid name for NIRCam occulter: " + self.name)
 
+        # EDIT: updated on 8 Dec 2021 to grab offsets directly from pySIAF
+        self.siaf = pysiaf.Siaf('NIRCAM')
+        self.offset_swb = {filt: self.get_bar_offset_from_siaf(filt, channel='SW')
+                           for filt in ["F182M", "F187N", "F210M", "F212N", "F200W", 'narrow']}
+        self.offset_lwb = {filt: self.get_bar_offset_from_siaf(filt, channel='LW')
+                           for filt in ["F250M", "F300M", "F277W", "F335M", "F360M", "F356W", "F410M", "F430M", "F460M", "F480M", "F444W", 'narrow']}
+
         if bar_offset is None and auto_offset is not None:
             offsets = self.offset_swb if self.name.lower() == 'maskswb' else self.offset_lwb
             try:
@@ -773,6 +757,22 @@ def __init__(self, name="unnamed BLC", kind='nircamcircular', module='A', nd_squ
         else:
             self.bar_offset = None
 
+    def get_bar_offset_from_siaf(self, filt, channel='LW'):
+        """ Get bar offset directly from SIAF.
+        
+        """
+
+        if channel == 'SW':
+            refapername = 'NRCA4_MASKSWB'
+            apername = 'NRCA4_MASKSWB_' + filt.upper()
+        else: # otherwise default to LW
+            refapername = 'NRCA5_MASKLWB'
+            apername = 'NRCA5_MASKLWB_' + filt.upper()
+        offset_arcsec = np.sqrt((self.siaf.apertures[refapername].V2Ref - self.siaf.apertures[apername].V2Ref)**2 + (self.siaf.apertures[refapername].V3Ref - self.siaf.apertures[apername].V3Ref)**2)
+        sign = np.sign(self.siaf.apertures[refapername].V2Ref - self.siaf.apertures[apername].V2Ref)
+
+        return sign * offset_arcsec
+
     def get_transmission(self, wave):
         """ Compute the amplitude transmission appropriate for a BLC for some given pixel spacing
         corresponding to the supplied Wavefront.