1 files changed, 28 insertions, 0 deletions
diff --git a/lib/stwcs/updatewcs/utils.py b/lib/stwcs/updatewcs/utils.py
new file mode 100644
index 0000000..29ba5f3
--- /dev/null
+++ b/lib/stwcs/updatewcs/utils.py
@@ -0,0 +1,28 @@
+from __future__ import division # confidence high
+
+def diff_angles(a,b):
+    """ 
+    Perform angle subtraction a-b taking into account
+    small-angle differences across 360degree line. 
+    """
+    
+    diff = a - b
+    
+    if diff > 180.0:
+        diff -= 360.0
+
+    if diff < -180.0:
+        diff += 360.0
+    
+    return diff
+
+def getBinning(fobj, extver=1):
+    # Return the binning factor
+    binned = 1
+    if fobj[0].header['INSTRUME'] == 'WFPC2':
+        mode = fobj[0].header.get('MODE', "")
+        if mode == 'AREA': binned = 2
+    else:
+        binned = fobj['SCI', extver].header.get('BINAXIS',1)
+    return binned
+