Handle zero length arrays.

desihub · Jan 19, 2021 · 843f799 · 843f799
1 parent f551578
commit 843f799
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/py/desisurvey/tiles.py b/py/desisurvey/tiles.py
@@ -183,6 +183,8 @@ def airmass_at_mjd(self, mjd, mask=None):
         array
             Array of airmasses corresponding to each input hour angle.
         """
+        if len(mjd) == 0:
+            return np.zeros(0, dtype='f8')
         tt = Time(mjd, format='mjd', location=desisurvey.utils.get_location())
         lst = tt.sidereal_time('apparent').to(u.deg).value