diff --git a/src/aare/daq/operations/raster/service.py b/src/aare/daq/operations/raster/service.py
index 53204387..02561827 100644
--- a/src/aare/daq/operations/raster/service.py
+++ b/src/aare/daq/operations/raster/service.py
@@ -362,8 +362,6 @@ class RasterService:
                 )
             else:
                 scan_result = self.ctx.jfjoch.wait_till_done(60)
-                com = None
-
                 if scan_result is None:
                     self.logger.error(
                         "JFJoch returned no ScanResult for raster",
@@ -373,32 +371,46 @@ class RasterService:
                             {"exp_time_s": request.exp_time_s},
                         ),
                     )
+                    raise RasterScanException("JFJoch returned no ScanResult for raster")
 
-                if request.n_x == 1:
-                    x = request.grid_size_mm.x / 2.0
-                else:
-                    x = ((request.n_x - 1) * request.grid_size_mm.x) / 2.0
-                y = ((request.n_y - 1) * request.grid_size_mm.y) / 2.0
-
-                target_coor_offset = self.ctx.sample_geometry.smargon_nudge(Coordinate(x=x, y=y))
-
-                self.logger.info(
-                    "Calculated raster centre offset",
-                    extra=merge_log_context(
-                        sample_log_context(self.ctx.sample),
-                        raster_request_log_context(request),
-                        {
-                            "centre_offset_x_mm": target_coor_offset.x,
-                            "centre_offset_y_mm": target_coor_offset.y,
-                            "centre_offset_z_mm": target_coor_offset.z,
-                            "grid_half_width_x_mm": x,
-                            "grid_half_height_y_mm": y,
-                            "top_left_x_mm": getattr(request.smargon_top_left.sh_mm, "x", None),
-                            "top_left_y_mm": getattr(request.smargon_top_left.sh_mm, "y", None),
-                            "top_left_z_mm": getattr(request.smargon_top_left.sh_mm, "z", None),
-                        },
-                    ),
+                result_array = create_quality_filtered_array(
+                    scan_result.images,
+                    "spots_low_res",
+                    min_spots=None,
+                    min_efficiency=1.0,
+                    min_background=None,
+                    min_low_res_spots=None,
                 )
+                com = raster_centre_of_mass(result_array, scan_result.images)
+                if com is None:
+                    if request.n_x == 1:
+                        x = request.grid_size_mm.x / 2.0
+                    else:
+                        x = ((request.n_x - 1) * request.grid_size_mm.x) / 2.0
+                    y = ((request.n_y - 1) * request.grid_size_mm.y) / 2.0
+
+                    target_coor_offset = self.ctx.sample_geometry.smargon_nudge(Coordinate(x=x, y=y))
+
+                    self.logger.info(
+                        "Calculated raster centre offset",
+                        extra=merge_log_context(
+                            sample_log_context(self.ctx.sample),
+                            raster_request_log_context(request),
+                            {
+                                "centre_offset_x_mm": target_coor_offset.x,
+                                "centre_offset_y_mm": target_coor_offset.y,
+                                "centre_offset_z_mm": target_coor_offset.z,
+                                "grid_half_width_x_mm": x,
+                                "grid_half_height_y_mm": y,
+                                "top_left_x_mm": getattr(request.smargon_top_left.sh_mm, "x", None),
+                                "top_left_y_mm": getattr(request.smargon_top_left.sh_mm, "y", None),
+                                "top_left_z_mm": getattr(request.smargon_top_left.sh_mm, "z", None),
+                            },
+                        ),
+                    )
+                else:
+                    target_coor = com.get_com_mm(request)
+                    target_coor_offset = self.ctx.sample_geometry.smargon_nudge(target_coor)
 
                 self.logger.info(f"moving Smargon to grid centre offset {target_coor_offset}")
                 target_smargon = SmargonCoordinate(