diff --git a/gwemopt/scheduler.py b/gwemopt/scheduler.py
index 17d2bc5..9ce50c8 100644
--- a/gwemopt/scheduler.py
+++ b/gwemopt/scheduler.py
@@ -100,6 +100,7 @@ def get_order_heuristic(
         being the exposure time.
     Returns a list of tile indices in the order of observation.
     """
+
     keys = tile_struct.keys()
 
     exposureids_tiles = {}
@@ -205,7 +206,7 @@ def get_order_heuristic(
     idxs = -1 * np.ones((len(exposureids_tiles.keys()),))
     filts = ["n"] * len(exposureids_tiles.keys())
 
-    if nexps == 0:
+    if (nexps == 0) or (len(exposurelist) == 0):
         return idxs, filts
 
     if params["scheduleType"] == "airmass_weighted":
diff --git a/gwemopt/segments.py b/gwemopt/segments.py
index a51bfc2..1434c79 100644
--- a/gwemopt/segments.py
+++ b/gwemopt/segments.py
@@ -46,6 +46,9 @@ def get_telescope_segments(params):
 
 def get_moon_radecs(segmentlist, observer):
     dt = 1.0 / 24.0
+    if len(segmentlist) == 0:
+        return []
+
     tt = np.arange(segmentlist[0][0], segmentlist[-1][1] + dt, dt)
     tt_DJD = tt - MJD_TO_DJD
 
diff --git a/gwemopt/utils/parallel.py b/gwemopt/utils/parallel.py
new file mode 100644
index 0000000..b51e2f7
--- /dev/null
+++ b/gwemopt/utils/parallel.py
@@ -0,0 +1,22 @@
+import contextlib
+
+import joblib
+from tqdm import tqdm
+
+
+@contextlib.contextmanager
+def tqdm_joblib(tqdm_object):
+    """Context manager to patch joblib to report into tqdm progress bar given as argument"""
+
+    class TqdmBatchCompletionCallback(joblib.parallel.BatchCompletionCallBack):
+        def __call__(self, *args, **kwargs):
+            tqdm_object.update(n=self.batch_size)
+            return super().__call__(*args, **kwargs)
+
+    old_batch_callback = joblib.parallel.BatchCompletionCallBack
+    joblib.parallel.BatchCompletionCallBack = TqdmBatchCompletionCallback
+    try:
+        yield tqdm_object
+    finally:
+        joblib.parallel.BatchCompletionCallBack = old_batch_callback
+        tqdm_object.close()