diff --git a/tangostationcontrol/tangostationcontrol/test/beam/test_delays.py b/tangostationcontrol/tangostationcontrol/test/beam/test_delays.py
index 1eb036b7d2a77631e06565a4e44023ab1dee432a..4275b3e36c917e303cf82e2e42718d28c499054b 100644
--- a/tangostationcontrol/tangostationcontrol/test/beam/test_delays.py
+++ b/tangostationcontrol/tangostationcontrol/test/beam/test_delays.py
@@ -64,12 +64,16 @@ class TestAttributeTypes(base.TestCase):
         self.assertTrue(delays == [0.0])
 
     def test_light_second_delay(self):
+        """
+        This test measures the delay between 2 positions 1 light second apart.
+        """
+
         # # create a frame tied to the reference position
         reference_itrf = [3826577.066, 461022.948, 5064892.786]  # CS002LBA, in ITRF2005 epoch 2012.5
         d = delay_calculator(reference_itrf)
 
         # set the antenna position identical to the reference position
-        speed_of_light = 304389329.123#299792458.0
+        speed_of_light = 299792458.0
         antenna_itrf = [[reference_itrf[0], reference_itrf[1] - speed_of_light, reference_itrf[2]]]  # CS001LBA, in ITRF2005 epoch 2012.5
 
         # # set the timestamp to solve for
@@ -85,5 +89,5 @@ class TestAttributeTypes(base.TestCase):
         delays = d.convert(direction, antenna_itrf)
 
 
-        self.assertTrue(0.98 <= delays[0] <= 1.02)
+        self.assertTrue(0.98 <= delays[0] <= 1.02, f"delays[0] = {delays[0]}")