diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e951e91..fe611c3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -28,8 +28,8 @@ Run the tests with `make test`.
 
 Update extension in a working database with:
 ```
-ALTER EXTENSION observatory VERSION TO 'current';
-ALTER EXTENSION observatory VERSION TO 'dev';
+ALTER EXTENSION observatory UPDATE TO 'current';
+ALTER EXTENSION observatory UPDATE TO 'dev';
 ```
 
 Note: we keep the current development version install as 'dev' always;
diff --git a/NEWS.md b/NEWS.md
index ee2f4f5..0c1c9f3 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,11 @@
+1.9.0 (2018-02-14)
+------------------
+
+__Improvements__
+
+* Improved `OBS_GetAvailableTimespans` for the DO Timespans project ([bigmetadata/#422](https://github.com/CartoDB/bigmetadata/issues/422))
+* Fixed documentation
+
 1.8.0 (2017-10-18)
 ------------------
 
diff --git a/src/pg/observatory.control b/src/pg/observatory.control
index 84e7094..ee7a731 100644
--- a/src/pg/observatory.control
+++ b/src/pg/observatory.control
@@ -1,5 +1,5 @@
 comment = 'CartoDB Observatory backend extension'
-default_version = '1.8.0'
+default_version = '1.9.0'
 requires = 'postgis'
 superuser = true
 schema = cdb_observatory
diff --git a/src/pg/sql/42_observatory_exploration.sql b/src/pg/sql/42_observatory_exploration.sql
index 272eec2..3a271d9 100644
--- a/src/pg/sql/42_observatory_exploration.sql
+++ b/src/pg/sql/42_observatory_exploration.sql
@@ -405,6 +405,13 @@ BEGIN
 END
 $$ LANGUAGE plpgsql;
 
+DROP FUNCTION IF EXISTS cdb_observatory.OBS_GetAvailableTimespans(
+  bounds GEOMETRY,
+  filter_tags TEXT[],
+  numer_id TEXT,
+  denom_id TEXT,
+  geom_id TEXT
+);
 CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetAvailableTimespans(
   bounds GEOMETRY DEFAULT NULL,
   filter_tags TEXT[] DEFAULT NULL,
@@ -424,7 +431,9 @@ CREATE OR REPLACE FUNCTION cdb_observatory.OBS_GetAvailableTimespans(
   timespan_tags JSONB,
   valid_numer BOOLEAN,
   valid_denom BOOLEAN,
-  valid_geom BOOLEAN
+  valid_geom BOOLEAN,
+  timespan_alias TEXT,
+  timespan_range DATERANGE
 ) AS $$
 DECLARE
   geom_clause TEXT;
@@ -448,12 +457,14 @@ BEGIN
            NULL::TEXT timespan_aggregate,
            NULL::TEXT timespan_license,
            NULL::TEXT timespan_source,
-           NULL::TEXT timespan_type,
+           timespan_type::TEXT,
            NULL::JSONB timespan_extra,
            NULL::JSONB timespan_tags,
-    $1 = ANY(numers) valid_numer,
-    $2 = ANY(denoms) valid_denom,
-    $3 = ANY(geoms) valid_geom_id
+    COALESCE($1 = ANY(numers), false) valid_numer,
+    COALESCE($2 = ANY(denoms), false) valid_denom,
+    COALESCE($3 = ANY(geoms), false) valid_geom_id,
+           timespan_alias::TEXT,
+           timespan_range::DATERANGE
     FROM observatory.obs_meta_timespan
     WHERE %s (timespan_tags ?& $4 OR CARDINALITY($4) = 0)
   $string$, geom_clause)