diff --git a/src/sorcha/ephemeris/simulation_driver.py b/src/sorcha/ephemeris/simulation_driver.py
index cb742c92..0417522d 100644
--- a/src/sorcha/ephemeris/simulation_driver.py
+++ b/src/sorcha/ephemeris/simulation_driver.py
@@ -80,6 +80,8 @@ def create_ephemeris(orbits_df, pointings_df, args, sconfigs):
         nside : integer
             The nside value used for the HEALPIx calculations.  Must be a
             power of 2 (1, 2, 4, ...)  nside=64 is current default.
+        n_sub_intervals: int
+            Number of sub-intervals for the Lagrange interpolation (default: 101)
 
     Returns
     -------
@@ -109,7 +111,7 @@ def create_ephemeris(orbits_df, pointings_df, args, sconfigs):
     picket_interval = sconfigs.simulation.ar_picket
     obsCode = sconfigs.simulation.ar_obs_code
     nside = 2**sconfigs.simulation.ar_healpix_order
-    n_sub_intervals = 101  # configs["n_sub_intervals"]
+    n_sub_intervals = sconfigs.simulation.ar_n_sub_intervals
 
     ephemeris_csv_filename = None
     if args.output_ephemeris_file and args.outpath:
diff --git a/src/sorcha/utilities/sorchaConfigs.py b/src/sorcha/utilities/sorchaConfigs.py
index db9c1e74..e138d559 100644
--- a/src/sorcha/utilities/sorchaConfigs.py
+++ b/src/sorcha/utilities/sorchaConfigs.py
@@ -77,6 +77,9 @@ class simulationConfigs:
     ar_healpix_order: int = None
     """the order of healpix which we will use for the healpy portions of the code."""
 
+    ar_n_sub_intervals: int = 101
+    """Number of sub-intervals for the Lagrange ephemerides interpolation (default: 101)"""
+
     _ephemerides_type: str = None
     """Simulation used for ephemeris input."""
 
@@ -111,6 +114,7 @@ def _validate_simulation_configs(self):
             self.ar_fov_buffer = cast_as_float(self.ar_fov_buffer, "ar_fov_buffer")
             self.ar_picket = cast_as_int(self.ar_picket, "ar_picket")
             self.ar_healpix_order = cast_as_int(self.ar_healpix_order, "ar_healpix_order")
+            self.ar_n_sub_intervals = cast_as_int(self.ar_n_sub_intervals, "ar_n_sub_intervals")
         elif self._ephemerides_type == "external":
             # makes sure when these are not needed that they are not populated
             check_key_doesnt_exist(self.ar_ang_fov, "ar_ang_fov", "but ephemerides type is external")
@@ -1512,6 +1516,7 @@ def PrintConfigsToLog(sconfigs, cmd_args):
         pplogger.info("...the picket interval is: " + str(sconfigs.simulation.ar_picket))
         pplogger.info("...the observatory code is: " + str(sconfigs.simulation.ar_obs_code))
         pplogger.info("...the healpix order is: " + str(sconfigs.simulation.ar_healpix_order))
+        pplogger.info("...the number of sub-intervals is: " + str(sconfigs.simulation.ar_n_sub_intervals))
     else:
         pplogger.info("ASSIST+REBOUND Simulation is turned OFF.")
 
diff --git a/tests/data/test_PrintConfigsToLog.txt b/tests/data/test_PrintConfigsToLog.txt
index 49f5cf28..ad619826 100644
--- a/tests/data/test_PrintConfigsToLog.txt
+++ b/tests/data/test_PrintConfigsToLog.txt
@@ -224,6 +224,7 @@ sorcha.utilities.sorchaConfigs INFO     ...the buffer around the FOV is: 0.2
 sorcha.utilities.sorchaConfigs INFO     ...the picket interval is: 1 
 sorcha.utilities.sorchaConfigs INFO     ...the observatory code is: X05 
 sorcha.utilities.sorchaConfigs INFO     ...the healpix order is: 6 
+sorcha.utilities.sorchaConfigs INFO     ...the number of sub-intervals is: 101 
 sorcha.utilities.sorchaConfigs INFO     No lightcurve model is being applied. 
 sorcha.utilities.sorchaConfigs INFO     Output files will be saved in path: ./ with filestem testout 
 sorcha.utilities.sorchaConfigs INFO     Output files will be saved as format: csv 
diff --git a/tests/sorcha/test_sorchaConfigs.py b/tests/sorcha/test_sorchaConfigs.py
index 4d6f8bb3..59bfcde7 100644
--- a/tests/sorcha/test_sorchaConfigs.py
+++ b/tests/sorcha/test_sorchaConfigs.py
@@ -35,6 +35,7 @@
     "ar_picket": 1,
     "ar_obs_code": "X05",
     "ar_healpix_order": 6,
+    "ar_n_sub_intervals": 101
 }
 
 correct_filters_read = {"observing_filters": "r,g,i,z,u,y", "survey_name": "rubin_sim"}
@@ -261,7 +262,7 @@ def test_simulationConfigs_float(key_name):
     )
 
 
-@pytest.mark.parametrize("key_name", ["ar_picket", "ar_healpix_order"])
+@pytest.mark.parametrize("key_name", ["ar_picket", "ar_healpix_order","ar_n_sub_intervals"])
 def test_simulationConfigs_int(key_name):
     """
     Tests that wrong inputs for simulationConfigs int attributes is caught correctly