diff --git a/p2obp/backend/compose.py b/p2obp/backend/compose.py
index 0d9ca52..b9e0585 100644
--- a/p2obp/backend/compose.py
+++ b/p2obp/backend/compose.py
@@ -214,14 +214,14 @@ def fill_header(target: Dict,
     header : dict
     """
     header = {}
-    header_user = load_template(TEMPLATE_FILE,
-                                "header", sub_header="user")
-    header_target = load_template(TEMPLATE_FILE,
-                                  "header", sub_header="target")
-    header_constraints = load_template(TEMPLATE_FILE,
-                                       "header", sub_header="constraints")
-    header_observation = load_template(TEMPLATE_FILE,
-                                       "header", sub_header="observation")
+    header_user = load_template(
+            TEMPLATE_FILE, "header", sub_header="user")
+    header_target = load_template(
+            TEMPLATE_FILE, "header", sub_header="target")
+    header_constraints = load_template(
+            TEMPLATE_FILE, "header", sub_header="constraints")
+    header_observation = load_template(
+            TEMPLATE_FILE, "header", sub_header="observation")
     ob_name = set_ob_name(target, observation_type, sci_name, tag)
     ra_hms, dec_dms = format_ra_and_dec(target)
     prop_ra, prop_dec = format_proper_motions(target)
@@ -242,6 +242,7 @@ def fill_header(target: Dict,
     header_constraints["atm"] = TURBULENCE[OPTIONS["constraints.turbulence"]]
     header_constraints["sky_transparency"] =\
         SKY_TRANSPARENCY[OPTIONS["constraints.transparency"]]
+    header_constraints["watervapour"] = OPTIONS["constraints.pwv"]
     if "ut" in array_configuration:
         header_constraints["moon_angular_distance"] = 10
 
diff --git a/p2obp/backend/options.py b/p2obp/backend/options.py
index 3da2c37..91c7ba1 100644
--- a/p2obp/backend/options.py
+++ b/p2obp/backend/options.py
@@ -66,8 +66,9 @@
 OPTIONS["dit.gra4mat.uts.high"] = 0.6
 
 # NOTE: Set the weather constraints.
-OPTIONS["constraints.turbulence"] = 70
-OPTIONS["constraints.transparency"] = "thin"
+OPTIONS["constraints.pwv"] = 10
+OPTIONS["constraints.turbulence"] = 30
+OPTIONS["constraints.transparency"] = "clear"
 
 # NOTE: The settings for the `query`-script.
 OPTIONS["catalogs"] = ["gaia", "tycho", "nomad",