edited error message

nataliekorzh · nataliekorzh · commit e3379b29fc63 · 2021-01-08T12:16:21.000-05:00
diff --git a/astroquery/mast/observations.py b/astroquery/mast/observations.py
@@ -428,7 +428,7 @@ def get_product_list_async(self, observations):
             response : list of `~requests.Response`
         """
         if len(observations) == 0 or not observations["obsid"]:
-            raise InvalidQueryError("Observation list is empty.")
+            raise InvalidQueryError("Observation list is empty, no associated products.")
 
         # getting the obsid list
         if isinstance(observations, Row):
