diff --git a/cosipy/response/ExtendedSourceResponse.py b/cosipy/response/ExtendedSourceResponse.py
index 425c4d62..9cf06930 100644
--- a/cosipy/response/ExtendedSourceResponse.py
+++ b/cosipy/response/ExtendedSourceResponse.py
@@ -1,5 +1,6 @@
 from histpy import Histogram, Axes, Axis
 import numpy as np
+import astropy.units as u
 
 from .functions import get_integrated_extended_model
 
@@ -84,8 +85,19 @@ def get_expectation(self, allsky_image_model):
         Histogram
             A histogram representing the calculated expectation.
         """
-        return Histogram(edges=self.axes[2:],
-                         contents=np.tensordot(allsky_image_model.contents, self.contents, axes=([0,1], [0,1])) * self.axes[0].pixarea())
+        if self.axes[0].label == allsky_image_model.axes[0].label \
+            and self.axes[1].label == allsky_image_model.axes[1].label \
+            and np.all(self.axes[0].edges == allsky_image_model.axes[0].edges) \
+            and np.all(self.axes[1].edges == allsky_image_model.axes[1].edges) \
+            and allsky_image_model.unit == u.Unit('1/(s*cm*cm*sr)'):
+            
+            contents = np.tensordot(allsky_image_model.contents, self.contents, axes=([0,1], [0,1]))
+            contents *= self.axes[0].pixarea()
+
+            return Histogram(edges=self.axes[2:], contents=contents)
+        
+        else:
+            raise ValueError(f"The input allskymodel mismatches with the extended source response.")
 
     def get_expectation_from_astromodel(self, source):
         """