diff --git a/adsmp/solr_updater.py b/adsmp/solr_updater.py
index d8c103a..eb3a988 100644
--- a/adsmp/solr_updater.py
+++ b/adsmp/solr_updater.py
@@ -179,7 +179,7 @@ def extract_classifications_pipeline(db_classifications, solrdoc):
     """retrieve expected classifier collections
 
     classifications is a solr virtual field so it should never be set"""
-    db_classifications = [element for element in (db_classifications or []) if element] # remove empty strings
+    db_classifications = [element for element in (db_classifications or []) if element in config.get("EXPOSE_COLLECTIONS")] # remove empty strings
     if db_classifications is None or len(db_classifications) == 0:
         return {"database" : solrdoc.get("database", None)}
 
diff --git a/config.py b/config.py
index b4934cb..dcb4066 100644
--- a/config.py
+++ b/config.py
@@ -150,4 +150,10 @@
     "title",
     "doctype",
     "pub_raw"
-]
\ No newline at end of file
+]
+
+EXPOSE_COLLECTIONS = [
+    "astrophysics",
+    "heliophysics",
+    "planetary"
+    ]