BUG: fix handling of nan input for Time properties

CHANGES.rst

@@ -28,6 +28,9 @@
 
 - Fixed TapResults to inherit session. [#447]
 
+- Fix handling of nan values for Time properties in SIA2 records. [#463]
+
+
 1.4.1 (2023-03-07)
 ==================
 

pyvo/dal/sia2.py

@@ -11,6 +11,7 @@
 """
 
 import warnings
+import numpy as np
 
 from astropy import units as u
 from astropy.time import Time
@@ -880,20 +881,30 @@ def t_ref_pos(self):
     @property
     def t_min(self):
         """
-        The start time of the observation specified in MJD. In case of data
-        products result of the combination of multiple frames, min time must
-        be the minimum of the start times
+        The start time of the observation specified in MJD as an
+        `~astropy.time.Time` instance. In case of data products result of the
+        combination of multiple frames, min time must be the minimum of the
+        start times. ``None`` is used for NaN response values.
         """
-        return Time(self.get('t_min'), format='mjd')
+        t_min = self.get('t_min')
+        if np.isfinite(t_min):
+            return Time(t_min, format='mjd')
+        else:
+            return None
 
     @property
     def t_max(self):
         """
-        The stop time of the observation specified in MJD. In case of data
-        products result of the combination of multiple frames, t_max must
-        be the maximum of the stop times
+        The stop time of the observation specified in MJD as an
+        `~astropy.time.Time` instance. In case of data products result of the
+        combination of multiple frames, t_max must be the maximum of the
+        stop times. ``None`` is used for NaN response values.
         """
-        return Time(self.get('t_min'), format='mjd')
+        t_max = self.get('t_max')
+        if np.isfinite(t_max):
+            return Time(t_max, format='mjd')
+        else:
+            return None
 
     @property
     def t_exptime(self):