diff --git a/python/lsst/ap/association/loadDiaCatalogs.py b/python/lsst/ap/association/loadDiaCatalogs.py
index 01204ee4..8c196c2d 100644
--- a/python/lsst/ap/association/loadDiaCatalogs.py
+++ b/python/lsst/ap/association/loadDiaCatalogs.py
@@ -157,7 +157,7 @@ def run(self, regionTime):
         # Load diaSources and forced sources up to the time of the exposure
         # The timespan may include significant padding, so use the midpoint to
         #  avoid missing valid recent diaSources.
-        visitTime = getMidpointFromTimespan(regionTime.timespan).tai
+        visitTime = getMidpointFromTimespan(regionTime.timespan)
 
         diaSources = self.loadDiaSources(diaObjects, region, visitTime, schema)
 
diff --git a/python/lsst/ap/association/mpSkyEphemerisQuery.py b/python/lsst/ap/association/mpSkyEphemerisQuery.py
index 5dfc8362..ab532eff 100644
--- a/python/lsst/ap/association/mpSkyEphemerisQuery.py
+++ b/python/lsst/ap/association/mpSkyEphemerisQuery.py
@@ -125,7 +125,7 @@ def run(self, predictedRegionTime):
         timespan = predictedRegionTime.timespan
         expCenter = SpherePoint(region.getBoundingCircle().getCenter())
         expRadius = region.getBoundingCircle().getOpeningAngle().asDegrees()
-        expMidPointEPOCH = getMidpointFromTimespan(timespan, allowUnbounded=False).utc.mjd
+        expMidPointEPOCH = getMidpointFromTimespan(timespan, allowUnbounded=False).mjd
 
         # MPSky service query
         mpSkyURL = os.environ.get('MP_SKY_URL', '')
diff --git a/python/lsst/ap/association/utils.py b/python/lsst/ap/association/utils.py
index 8ea62c9c..dc87f740 100644
--- a/python/lsst/ap/association/utils.py
+++ b/python/lsst/ap/association/utils.py
@@ -250,13 +250,13 @@ def getMidpointFromTimespan(timespan, allowUnbounded=True):
 
     try:
         interval = timespan.end - timespan.begin
-        return timespan.begin + interval/2
+        return (timespan.begin + interval/2).tai
     except TypeError as e:
         if allowUnbounded:
             if timespan.end is not None:
-                return timespan.end
+                return timespan.end.tai
             elif timespan.begin is not None:
-                return timespan.begin
+                return timespan.begin.tai
             else:
                 raise ValueError("Cannot compute midpoint: unbounded timespan.") from e
         else:
diff --git a/tests/test_loadDiaCatalogs.py b/tests/test_loadDiaCatalogs.py
index 41883137..2a64013c 100644
--- a/tests/test_loadDiaCatalogs.py
+++ b/tests/test_loadDiaCatalogs.py
@@ -74,7 +74,7 @@ def setUp(self):
 
         self.exposure = makeExposure(False, False)
         self.regionTime = makeRegionTime(exposure=self.exposure)
-        self.dateTime = getMidpointFromTimespan(self.regionTime.timespan).tai
+        self.dateTime = getMidpointFromTimespan(self.regionTime.timespan)
 
         self.diaObjects = makeDiaObjects(20, self.exposure, rng)
         self.diaSources = makeDiaSources(
diff --git a/tests/test_utils.py b/tests/test_utils.py
index b8efd40f..7ae843f0 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -65,7 +65,7 @@ def test_regionTime_timespan(self):
         exposure = makeExposure()
         regionTime = makeRegionTime(exposure)
         visitTime = exposure.visitInfo.date.toAstropy()
-        midpoint = getMidpointFromTimespan(regionTime.timespan).tai
+        midpoint = getMidpointFromTimespan(regionTime.timespan)
         self.assertEqual(visitTime.jd, midpoint.jd)
 
     def test_invalidTimespan(self):