diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/migrations/0048_indices.py b/SAS/TMSS/backend/src/tmss/tmssapp/migrations/0048_indices.py
new file mode 100644
index 0000000000000000000000000000000000000000..45953a20e3c9a3ee8817d42e4ae0ef6ec53cc8a8
--- /dev/null
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/migrations/0048_indices.py
@@ -0,0 +1,53 @@
+# Generated by Django 3.0.9 on 2023-09-13 15:53
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('tmssapp', '0047_schedulingconstraintsweightfactor'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='observed_start_time',
+            field=models.DateTimeField(db_index=True, default=None, editable=False, help_text='The earliest on_sky_start_time of all the finished/observed observation tasks.', null=True),
+        ),
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='observed_stop_time',
+            field=models.DateTimeField(db_index=True, default=None, editable=False, help_text='The latest on_sky_stop_time of all the finished/observed observation tasks.', null=True),
+        ),
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='obsolete_since',
+            field=models.DateTimeField(db_index=True, default=None, editable=False, help_text='When was the first of the subtask(s) marked obsolete, or NULL if not obsolete (NULLable).', null=True),
+        ),
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='on_sky_start_time',
+            field=models.DateTimeField(db_index=True, default=None, editable=False, help_text='The earliest on_sky_start_time of all the observation tasks.', null=True),
+        ),
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='on_sky_stop_time',
+            field=models.DateTimeField(db_index=True, default=None, editable=False, help_text='The latest on_sky_stop_time of all the observation tasks.', null=True),
+        ),
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='process_start_time',
+            field=models.DateTimeField(db_index=True, default=None, editable=False, help_text='The earliest process_start_time of all the tasks.', null=True),
+        ),
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='process_stop_time',
+            field=models.DateTimeField(db_index=True, default=None, editable=False, help_text='The latest process_stop_time of all the tasks.', null=True),
+        ),
+        migrations.AlterField(
+            model_name='schedulingunitblueprint',
+            name='results_accepted',
+            field=models.BooleanField(db_index=True, default=None, help_text='boolean (default None) which indicates whether this unit was accepted as successful or not.', null=True),
+        ),
+    ]
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/models/specification.py b/SAS/TMSS/backend/src/tmss/tmssapp/models/specification.py
index 5ac21bcca828a7eb3abed22fd8fc343b3033dd9d..5edd16e6c822a04b35994341fa6518cf7bcf9b2c 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/models/specification.py
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/models/specification.py
@@ -1242,18 +1242,18 @@ class SchedulingUnitBlueprint(ProjectPropertyMixin, TemplateSchemaMixin, Schedul
 
     # these start/stop times are aggregated results over this task's start/stop times
     # they are computed/updated in the database using sql triggers upon subtask inserts/updates.
-    process_start_time = DateTimeField(null=True, default=None, editable=False, help_text='The earliest process_start_time of all the tasks.')
-    process_stop_time = DateTimeField(null=True, default=None, editable=False, help_text='The latest process_stop_time of all the tasks.')
-    on_sky_start_time = DateTimeField(null=True, default=None, editable=False, help_text='The earliest on_sky_start_time of all the observation tasks.')
-    on_sky_stop_time = DateTimeField(null=True, default=None, editable=False, help_text='The latest on_sky_stop_time of all the observation tasks.')
-    observed_start_time = DateTimeField(null=True, default=None, editable=False, help_text='The earliest on_sky_start_time of all the finished/observed observation tasks.')
-    observed_stop_time = DateTimeField(null=True, default=None, editable=False, help_text='The latest on_sky_stop_time of all the finished/observed observation tasks.')
+    process_start_time = DateTimeField(null=True, default=None, editable=False, db_index=True, help_text='The earliest process_start_time of all the tasks.')
+    process_stop_time = DateTimeField(null=True, default=None, editable=False, db_index=True, help_text='The latest process_stop_time of all the tasks.')
+    on_sky_start_time = DateTimeField(null=True, default=None, editable=False, db_index=True, help_text='The earliest on_sky_start_time of all the observation tasks.')
+    on_sky_stop_time = DateTimeField(null=True, default=None, editable=False, db_index=True, help_text='The latest on_sky_stop_time of all the observation tasks.')
+    observed_start_time = DateTimeField(null=True, default=None, editable=False, db_index=True, help_text='The earliest on_sky_start_time of all the finished/observed observation tasks.')
+    observed_stop_time = DateTimeField(null=True, default=None, editable=False, db_index=True, help_text='The latest on_sky_stop_time of all the finished/observed observation tasks.')
     on_sky_duration = DurationField(null=True, editable=False, help_text='The total scheduled/actual duration the observation tasks were on sky (NULLable).')
     observed_duration = DurationField(null=True, editable=False, help_text='The total actual duration that the finished/observed observation tasks were on sky (NULLable).')
     duration = DurationField(null=True, editable=False, help_text='The scheduled/actual duration for the full task (NULLable).')
 
     # obsolete_since and status are also computed/updated in the database using sql triggers upon subtask inserts/updates.
-    obsolete_since = DateTimeField(null=True, default=None, editable=False, help_text='When was the first of the subtask(s) marked obsolete, or NULL if not obsolete (NULLable).')
+    obsolete_since = DateTimeField(null=True, default=None, editable=False, db_index=True, help_text='When was the first of the subtask(s) marked obsolete, or NULL if not obsolete (NULLable).')
     status = ForeignKey('SchedulingUnitStatus', null=False, editable=False, default='defined', on_delete=PROTECT, help_text='The SchedulingUnit status - derived from the combined task statuses.')
 
     # please note that the most fields below are immutable at db level (See SQL triggers)
@@ -1269,7 +1269,7 @@ class SchedulingUnitBlueprint(ProjectPropertyMixin, TemplateSchemaMixin, Schedul
     scheduling_constraints_doc = JSONField(help_text='Scheduling Constraints for this run.', null=True)
     scheduling_constraints_template = ForeignKey('SchedulingConstraintsTemplate', on_delete=CASCADE, null=True, help_text='Schema used for scheduling_constraints_doc.')
     interrupts_telescope = BooleanField(default=False, null=False, help_text='boolean (default FALSE), which indicates whether this observation was triggered (responsive telescope)')
-    results_accepted = BooleanField(default=None, null=True, help_text='boolean (default None) which indicates whether this unit was accepted as successful or not.')
+    results_accepted = BooleanField(default=None, null=True, db_index=True, help_text='boolean (default None) which indicates whether this unit was accepted as successful or not.')
     global_identifier = OneToOneField('SIPidentifier', null=False, editable=False, on_delete=PROTECT, help_text='The global unique identifier for LTA SIP.')
     path_to_project = 'draft__scheduling_set__project'
     placed = BooleanField(default=False, db_index=True, null=False, help_text='Was this unit placed by the scheduler, or are the scheduled_start/stop_time just best guesses?')
diff --git a/SAS/TMSS/backend/src/tmss/tmssapp/viewsets/specification.py b/SAS/TMSS/backend/src/tmss/tmssapp/viewsets/specification.py
index 5906a898d156ab56da522877128ef62baa655a65..b3f5710d0e33c6d73082151af2b651a62d7f67cb 100644
--- a/SAS/TMSS/backend/src/tmss/tmssapp/viewsets/specification.py
+++ b/SAS/TMSS/backend/src/tmss/tmssapp/viewsets/specification.py
@@ -311,10 +311,8 @@ class ReservationPropertyFilter(property_filters.PropertyFilterSet):
     id_min = filters.NumberFilter(field_name='id', lookup_expr='gte')
     id_max = filters.NumberFilter(field_name='id', lookup_expr='lte')
     project = filters.CharFilter(field_name='project__name', lookup_expr='icontains')
-    start_time_min = filters.DateTimeFilter(field_name='start_time', lookup_expr='gte')
-    start_time_max = filters.DateTimeFilter(field_name='start_time', lookup_expr='lte')
-    stop_time_min = filters.DateTimeFilter(field_name='stop_time', lookup_expr='gte')
-    stop_time_max = filters.DateTimeFilter(field_name='stop_time', lookup_expr='lte')
+    start_time = filters.IsoDateTimeFromToRangeFilter(field_name='start_time')
+    stop_time = filters.IsoDateTimeFromToRangeFilter(field_name='stop_time')
     stop_time_isnull = filters.BooleanFilter(field_name='stop_time', lookup_expr='isnull')
     duration_min = property_filters.PropertyNumberFilter(field_name='duration', lookup_expr='gte')
     duration_max = property_filters.PropertyNumberFilter(field_name='duration', lookup_expr='lte')
@@ -923,8 +921,8 @@ class SchedulingUnitBlueprintSlimPropertyFilter(property_filters.PropertyFilterS
     '''A small 'slim' PropertyFilterSet for the most relevant properties.'''
     on_sky_start_time = filters.IsoDateTimeFromToRangeFilter(field_name='on_sky_start_time')
     on_sky_stop_time = filters.IsoDateTimeFromToRangeFilter(field_name='on_sky_stop_time')
-    scheduled_start_time = filters.IsoDateTimeFromToRangeFilter(field_name='scheduled_start_time')
-    scheduled_stop_time = filters.IsoDateTimeFromToRangeFilter(field_name='scheduled_stop_time')
+    process_start_time = filters.IsoDateTimeFromToRangeFilter(field_name='process_start_time')
+    process_stop_time = filters.IsoDateTimeFromToRangeFilter(field_name='process_stop_time')
     project = filters.CharFilter(field_name='draft__scheduling_set__project__name', lookup_expr='icontains')
     status = filters.MultipleChoiceFilter(field_name='status', choices=[(c.value, c.value) for c in models.SchedulingUnitStatus.Choices])
     id = NumberInFilter(field_name='id', lookup_expr='in')