diff --git a/atlas/tasks.py b/atlas/tasks.py
index 26b7a769..fc7234d4 100644
--- a/atlas/tasks.py
+++ b/atlas/tasks.py
@@ -3,11 +3,15 @@ from django.core.mail import send_mail
 from django.http import HttpResponse
 from django.shortcuts import get_object_or_404
 from celery import shared_task
-from atlas.models import Case
+from atlas.models import Case, Series, SeriesImage
 from generic.models import CimarCase
 from rad.settings import REMOTE_URL, CIMAR_USERNAME, CIMAR_PASSWORD
 from helpers.cimar import CimarAPI, NotFoundError
 from pydicom.uid import generate_uid
+from django.contrib.auth.models import User
+from django.core.files.base import ContentFile
+import copy
+import io
 
 @shared_task()
 def push_case_to_cimar_task(case_id):
@@ -49,4 +53,246 @@ def push_case_to_cimar_task(case_id):
 
     cimar_case.refresh_study()
 
-    return 10
\ No newline at end of file
+    return 10
+
+
+@shared_task(bind=True)
+def series_reconstruct_task(
+    self,
+    series_id,
+    user_id,
+    recon_planes,
+    slice_thickness_val=None,
+    slice_spacing_val=None,
+    recon_thickness_mode="mean",
+):
+    """Generate reconstructions asynchronously for a series with progress updates."""
+    import numpy as np
+    from loguru import logger
+    from atlas import views as atlas_views
+
+    series = get_object_or_404(Series, pk=series_id)
+    user = get_object_or_404(User, pk=user_id)
+
+    if not series.check_user_can_edit(user):
+        raise PermissionError("Permission denied")
+
+    images = list(series.get_images())
+    dicom_items = []
+    for image in images:
+        ds = atlas_views._read_series_image_dataset(image)
+        if ds is None:
+            continue
+        try:
+            arr = ds.pixel_array
+            if arr.ndim != 2:
+                continue
+            dicom_items.append((image, ds, arr))
+        except Exception:
+            continue
+
+    if len(dicom_items) < 2:
+        raise ValueError("Need at least 2 valid DICOM images in series for reconstruction")
+
+    base_shape = dicom_items[0][2].shape
+    dicom_items = [item for item in dicom_items if item[2].shape == base_shape]
+    if len(dicom_items) < 2:
+        raise ValueError("Not enough consistently-sized slices for reconstruction")
+
+    geom = atlas_views._extract_recon_geometry(dicom_items)
+    sorted_items = geom["sorted_items"]
+    volume = np.stack([item[2] for item in sorted_items], axis=0)
+
+    template_ds = sorted_items[0][1]
+    source_positions_mm = geom["source_positions_mm"]
+    origin_ipp = geom["origin_ipp"]
+    row_dir = geom["row_dir"]
+    col_dir = geom["col_dir"]
+    normal_dir = geom["normal_dir"]
+    native_row_spacing = geom["row_spacing"]
+    native_col_spacing = geom["col_spacing"]
+    native_z_spacing = geom["native_z_spacing"]
+
+    target_spacing = float(slice_spacing_val) if slice_spacing_val is not None else native_z_spacing
+    slab_thickness = float(slice_thickness_val) if slice_thickness_val is not None else target_spacing
+
+    volume_for_recon, recon_centers_mm = atlas_views._aggregate_volume_along_z(
+        volume,
+        source_positions_mm,
+        float(target_spacing),
+        float(slab_thickness),
+        recon_thickness_mode,
+    )
+
+    if volume_for_recon.shape[0] < 1:
+        raise ValueError("No reconstruction slices were generated")
+
+    base_z_offset = float(recon_centers_mm[0]) if len(recon_centers_mm) > 0 else 0.0
+
+    def build_position(origin, row_vector, col_vector, stack_vector, row_index=0, col_index=0, stack_offset=0.0):
+        pos = (
+            np.asarray(origin, dtype=float)
+            + (np.asarray(stack_vector, dtype=float) * float(stack_offset))
+            + (np.asarray(row_vector, dtype=float) * (float(row_index) * float(native_row_spacing)))
+            + (np.asarray(col_vector, dtype=float) * (float(col_index) * float(native_col_spacing)))
+        )
+        return [float(pos[0]), float(pos[1]), float(pos[2])]
+
+    plane_slices = {}
+    for plane in recon_planes:
+        plane_norm = plane.lower()
+        if plane_norm == "axial":
+            recon_slices = [volume_for_recon[i, :, :] for i in range(volume_for_recon.shape[0])]
+            pixel_spacing_out = [native_row_spacing, native_col_spacing]
+            spacing_between_slices_out = float(target_spacing)
+            image_orientation_out = [
+                float(row_dir[0]),
+                float(row_dir[1]),
+                float(row_dir[2]),
+                float(col_dir[0]),
+                float(col_dir[1]),
+                float(col_dir[2]),
+            ]
+
+            def position_for_index(idx):
+                return build_position(
+                    origin_ipp,
+                    row_dir,
+                    col_dir,
+                    normal_dir,
+                    row_index=0,
+                    col_index=0,
+                    stack_offset=float(recon_centers_mm[idx]),
+                )
+        elif plane_norm == "coronal":
+            recon_slices = [volume_for_recon[:, i, :] for i in range(volume_for_recon.shape[1])]
+            pixel_spacing_out = [target_spacing, native_col_spacing]
+            spacing_between_slices_out = float(native_row_spacing)
+            image_orientation_out = [
+                float(normal_dir[0]),
+                float(normal_dir[1]),
+                float(normal_dir[2]),
+                float(col_dir[0]),
+                float(col_dir[1]),
+                float(col_dir[2]),
+            ]
+
+            def position_for_index(idx):
+                return build_position(
+                    origin_ipp,
+                    row_dir,
+                    col_dir,
+                    normal_dir,
+                    row_index=idx,
+                    col_index=0,
+                    stack_offset=base_z_offset,
+                )
+        elif plane_norm == "sagittal":
+            recon_slices = [volume_for_recon[:, :, i] for i in range(volume_for_recon.shape[2])]
+            pixel_spacing_out = [target_spacing, native_row_spacing]
+            spacing_between_slices_out = float(native_col_spacing)
+            image_orientation_out = [
+                float(normal_dir[0]),
+                float(normal_dir[1]),
+                float(normal_dir[2]),
+                float(row_dir[0]),
+                float(row_dir[1]),
+                float(row_dir[2]),
+            ]
+
+            def position_for_index(idx):
+                return build_position(
+                    origin_ipp,
+                    row_dir,
+                    col_dir,
+                    normal_dir,
+                    row_index=0,
+                    col_index=idx,
+                    stack_offset=base_z_offset,
+                )
+        else:
+            continue
+
+        plane_slices[plane_norm] = {
+            "recon_slices": recon_slices,
+            "pixel_spacing_out": pixel_spacing_out,
+            "spacing_between_slices_out": spacing_between_slices_out,
+            "image_orientation_out": image_orientation_out,
+            "position_for_index": position_for_index,
+        }
+
+    if not plane_slices:
+        raise ValueError("No valid reconstruction planes selected")
+
+    total_slices = sum(len(v["recon_slices"]) for v in plane_slices.values())
+    processed = 0
+    created_series = []
+
+    for plane_norm, cfg in plane_slices.items():
+        recon_series = atlas_views._create_series_derivative(series, f"Recon {plane_norm.title()}")
+        recon_series.series_instance_uid = generate_uid()
+        recon_series.save(update_fields=["series_instance_uid"])
+
+        for idx, arr2d in enumerate(cfg["recon_slices"]):
+            ds_new = copy.deepcopy(template_ds)
+            arr2d = np.asarray(arr2d, dtype=dicom_items[0][2].dtype)
+
+            ds_new.Rows = int(arr2d.shape[0])
+            ds_new.Columns = int(arr2d.shape[1])
+            ds_new.InstanceNumber = idx + 1
+            ds_new.SOPInstanceUID = generate_uid()
+            ds_new.SeriesInstanceUID = recon_series.series_instance_uid
+            ds_new.PixelData = arr2d.tobytes()
+            ds_new.PixelSpacing = [float(cfg["pixel_spacing_out"][0]), float(cfg["pixel_spacing_out"][1])]
+            ds_new.ImageOrientationPatient = cfg["image_orientation_out"]
+            ds_new.ImagePositionPatient = cfg["position_for_index"](idx)
+            ds_new.SliceThickness = float(slab_thickness)
+            ds_new.SpacingBetweenSlices = float(cfg["spacing_between_slices_out"])
+
+            out_io = io.BytesIO()
+            ds_new.save_as(out_io, write_like_original=False)
+            out_io.seek(0)
+
+            recon_image = SeriesImage(
+                series=recon_series,
+                position=idx + 1,
+                upload_filename=f"recon_{plane_norm}_{idx + 1}.dcm",
+            )
+            recon_image.image.save(
+                f"recon_{plane_norm}_{recon_series.pk}_{idx + 1}.dcm",
+                ContentFile(out_io.getvalue()),
+                save=False,
+            )
+            recon_image.save()
+
+            processed += 1
+            self.update_state(
+                state="PROGRESS",
+                meta={
+                    "current": processed,
+                    "total": total_slices,
+                    "message": f"Generating {plane_norm} reconstruction ({processed}/{total_slices})",
+                },
+            )
+
+        created_series.append(
+            {
+                "id": recon_series.pk,
+                "url": recon_series.get_absolute_url(),
+                "description": recon_series.description or str(recon_series.pk),
+            }
+        )
+
+    logger.info(
+        "Reconstruction task complete for series {} with {} outputs",
+        series.pk,
+        len(created_series),
+    )
+
+    return {
+        "series_id": series.pk,
+        "created_series": created_series,
+        "target_spacing": float(target_spacing),
+        "slab_thickness": float(slab_thickness),
+        "mode": recon_thickness_mode,
+    }
\ No newline at end of file
diff --git a/atlas/templates/atlas/series_viewer.html b/atlas/templates/atlas/series_viewer.html
index a295998b..e76869fe 100755
--- a/atlas/templates/atlas/series_viewer.html
+++ b/atlas/templates/atlas/series_viewer.html
@@ -294,10 +294,19 @@
 
                                             <div class="d-flex flex-wrap gap-2 mb-3">
                                                 <button id="truncate-test-modal-btn" class="btn btn-sm btn-outline-primary" type="button">Test preview</button>
-                                                <button class="btn btn-sm btn-danger" type="submit" name="operation" value="truncate">Apply truncate</button>
+                                                <button id="truncate-apply-btn" class="btn btn-sm btn-danger" type="submit" name="operation" value="truncate">Apply truncate</button>
                                                 <button class="btn btn-sm btn-outline-warning" type="submit" name="operation" value="remove_empty">Remove empty DICOMs</button>
                                             </div>
 
+                                            <div id="truncate-progress" class="d-none mb-3">
+                                                <div class="small text-warning mb-1">Applying truncate. Please wait...</div>
+                                                <div class="progress" style="height: 8px;">
+                                                    <div class="progress-bar progress-bar-striped progress-bar-animated bg-warning" style="width: 100%" role="progressbar" aria-valuenow="100" aria-valuemin="0" aria-valuemax="100"></div>
+                                                </div>
+                                            </div>
+
+                                            <div class="small text-muted mb-3">Truncate is a dedicated step. Downsample and reconstruction always run on the full active series.</div>
+
                                             <hr>
 
                                             <div class="mb-3">
@@ -443,6 +452,19 @@
                 endHidden.value = endInput.value;
             }
 
+            function updateBoundsInputs(startValue, endValue) {
+                const startInput = document.getElementById('truncate-lower-input');
+                const endInput = document.getElementById('truncate-upper-input');
+                if (!startInput || !endInput) {
+                    return;
+                }
+                startInput.value = String(startValue);
+                endInput.value = String(endValue);
+                startInput.max = String(endValue);
+                endInput.max = String(endValue);
+                syncOptimizeBounds();
+            }
+
             function getTruncateViewerElement() {
                 return document.getElementById(truncateApiKey);
             }
@@ -559,8 +581,46 @@
                 syncOptimizeBounds();
             });
 
+            document.body.addEventListener('htmx:beforeRequest', function (event) {
+                const form = document.getElementById('series-optimize-form');
+                if (!form || event.target !== form) {
+                    return;
+                }
+                const op = event.detail?.parameters?.operation || '';
+                const truncateProgress = document.getElementById('truncate-progress');
+                const truncateApplyBtn = document.getElementById('truncate-apply-btn');
+                if (op === 'truncate') {
+                    truncateProgress?.classList.remove('d-none');
+                    if (truncateApplyBtn) {
+                        truncateApplyBtn.disabled = true;
+                    }
+                }
+            });
+
+            document.body.addEventListener('htmx:afterRequest', function (event) {
+                const form = document.getElementById('series-optimize-form');
+                if (!form || event.target !== form) {
+                    return;
+                }
+                const truncateProgress = document.getElementById('truncate-progress');
+                const truncateApplyBtn = document.getElementById('truncate-apply-btn');
+                truncateProgress?.classList.add('d-none');
+                if (truncateApplyBtn) {
+                    truncateApplyBtn.disabled = false;
+                }
+            });
+
             document.body.addEventListener('htmx:afterSwap', function (event) {
                 if (event.target && event.target.id === 'series-optimize-feedback') {
+                    const truncatePayload = document.getElementById('truncate-range-payload');
+                    if (truncatePayload) {
+                        const start = parseInt(truncatePayload.dataset.start || '1', 10);
+                        const end = parseInt(truncatePayload.dataset.end || '1', 10);
+                        if (Number.isFinite(start) && Number.isFinite(end) && end >= start) {
+                            updateBoundsInputs(start, end);
+                        }
+                    }
+
                     const payload = document.getElementById('downsample-compare-payload');
                     if (!payload) {
                         return;
diff --git a/atlas/urls.py b/atlas/urls.py
index 80e1047e..f7b6a979 100755
--- a/atlas/urls.py
+++ b/atlas/urls.py
@@ -570,6 +570,11 @@ urlpatterns = [
             views.series_optimize_htmx,
             name="series_optimize",
         ),
+        path(
+            "series/<int:series_id>/reconstruct/status/<str:task_id>/",
+            views.series_reconstruct_status_htmx,
+            name="series_reconstruct_status",
+        ),
     path("series/<int:pk>/images/", views.series_images_partial, name="series_images"),
     path("series/<int:pk>/authors", views.SeriesAuthorUpdate.as_view(), name="series_authors"),
     path("series/<int:series_id>/finding/related", views.series_finding_related, name="series_finding_related"),
diff --git a/atlas/views.py b/atlas/views.py
index 0390c853..8a80fecd 100755
--- a/atlas/views.py
+++ b/atlas/views.py
@@ -163,7 +163,8 @@ from .filters import (
     NormalCaseFilter,
 )
 
-from .tasks import push_case_to_cimar_task
+from .tasks import push_case_to_cimar_task, series_reconstruct_task
+from celery.result import AsyncResult
 
 from django_tables2 import SingleTableView, SingleTableMixin
 from django_filters.views import FilterView
@@ -530,6 +531,7 @@ def series_optimize_htmx(request, series_id):
 
     images = list(series.get_images())
     bounded_images = [img for idx, img in enumerate(images) if idx >= start and idx <= end]
+    full_series_images = images
 
     if operation == "truncate":
         removed = []
@@ -542,8 +544,19 @@ def series_optimize_htmx(request, series_id):
 
         series.modified = Series.SeriesModifiedChocies.TR
         series.save(update_fields=["modified"])
+
+        new_total = int(series.get_image_count())
+        payload = (
+            f'<div id="truncate-range-payload" data-start="1" data-end="{new_total}" data-total="{new_total}"></div>'
+        )
         return HttpResponse(
-            f'<div class="alert alert-success mb-0">Truncate complete. Removed <strong>{len(removed)}</strong> images.</div>'
+            (
+                '<div class="alert alert-success mb-2">'
+                f'Truncate complete. Removed <strong>{len(removed)}</strong> images. '
+                f'Updated working range to <strong>1-{new_total}</strong>.'
+                '</div>'
+                f'{payload}'
+            )
         )
 
     if operation == "remove_empty":
@@ -573,7 +586,7 @@ def series_optimize_htmx(request, series_id):
             preview_series = _create_series_derivative(series, f"Downsample preview {downsample_pct}%")
             created = 0
 
-            for image in bounded_images:
+            for image in full_series_images:
                 ds = _read_series_image_dataset(image)
                 if ds is None:
                     continue
@@ -618,7 +631,7 @@ def series_optimize_htmx(request, series_id):
             )
 
         downsampled = []
-        for image in bounded_images:
+        for image in full_series_images:
             ds = _read_series_image_dataset(image)
             if ds is None:
                 continue
@@ -672,207 +685,106 @@ def series_optimize_htmx(request, series_id):
             return HttpResponse('<div class="alert alert-danger mb-0">Slice thickness must be greater than 0.</div>')
         if slice_spacing_val is not None and slice_spacing_val <= 0:
             return HttpResponse('<div class="alert alert-danger mb-0">Slice spacing must be greater than 0.</div>')
-
-        dicom_items = []
-        for image in bounded_images:
-            ds = _read_series_image_dataset(image)
-            if ds is None:
-                continue
-            try:
-                arr = ds.pixel_array
-                if arr.ndim != 2:
-                    continue
-                dicom_items.append((image, ds, arr))
-            except Exception:
-                continue
-
-        if len(dicom_items) < 2:
-            return HttpResponse('<div class="alert alert-warning mb-0">Need at least 2 valid DICOM images in range for reconstruction.</div>')
-
-        import numpy as np
-
-        base_shape = dicom_items[0][2].shape
-        dicom_items = [item for item in dicom_items if item[2].shape == base_shape]
-        if len(dicom_items) < 2:
-            return HttpResponse('<div class="alert alert-warning mb-0">Not enough consistently-sized slices for reconstruction.</div>')
-
-        geom = _extract_recon_geometry(dicom_items)
-        sorted_items = geom["sorted_items"]
-        volume = np.stack([item[2] for item in sorted_items], axis=0)
-
-        template_ds = sorted_items[0][1]
-        source_positions_mm = geom["source_positions_mm"]
-        origin_ipp = geom["origin_ipp"]
-        row_dir = geom["row_dir"]
-        col_dir = geom["col_dir"]
-        normal_dir = geom["normal_dir"]
-        native_row_spacing = geom["row_spacing"]
-        native_col_spacing = geom["col_spacing"]
-        native_z_spacing = geom["native_z_spacing"]
-
-        target_spacing = slice_spacing_val if slice_spacing_val is not None else native_z_spacing
-        slab_thickness = slice_thickness_val if slice_thickness_val is not None else target_spacing
-
-        try:
-            volume_for_recon, recon_centers_mm = _aggregate_volume_along_z(
-                volume,
-                source_positions_mm,
-                float(target_spacing),
-                float(slab_thickness),
-                recon_thickness_mode,
-            )
-        except Exception as exc:
-            logger.warning("Reconstruction aggregation failed for series {}: {}", series.pk, exc)
-            return HttpResponse('<div class="alert alert-danger mb-0">Failed to build reconstruction slabs for the requested spacing/thickness.</div>')
-
-        if volume_for_recon.shape[0] < 1:
-            return HttpResponse('<div class="alert alert-warning mb-0">No reconstruction slices were generated.</div>')
-
-        base_z_offset = float(recon_centers_mm[0]) if len(recon_centers_mm) > 0 else 0.0
-
-        def build_position(origin, row_vector, col_vector, stack_vector, row_index=0, col_index=0, stack_offset=0.0):
-            import numpy as np
-
-            pos = (
-                np.asarray(origin, dtype=float)
-                + (np.asarray(stack_vector, dtype=float) * float(stack_offset))
-                + (np.asarray(row_vector, dtype=float) * (float(row_index) * float(native_row_spacing)))
-                + (np.asarray(col_vector, dtype=float) * (float(col_index) * float(native_col_spacing)))
-            )
-            return [float(pos[0]), float(pos[1]), float(pos[2])]
-
-        created_series = []
-
-        for plane in recon_planes:
-            plane_norm = plane.lower()
-            if plane_norm == "axial":
-                recon_slices = [volume_for_recon[i, :, :] for i in range(volume_for_recon.shape[0])]
-                pixel_spacing_out = [native_row_spacing, native_col_spacing]
-                spacing_between_slices_out = float(target_spacing)
-                image_orientation_out = [
-                    float(row_dir[0]),
-                    float(row_dir[1]),
-                    float(row_dir[2]),
-                    float(col_dir[0]),
-                    float(col_dir[1]),
-                    float(col_dir[2]),
-                ]
-
-                def position_for_index(idx):
-                    return build_position(
-                        origin_ipp,
-                        row_dir,
-                        col_dir,
-                        normal_dir,
-                        row_index=0,
-                        col_index=0,
-                        stack_offset=float(recon_centers_mm[idx]),
-                    )
-            elif plane_norm == "coronal":
-                recon_slices = [volume_for_recon[:, i, :] for i in range(volume_for_recon.shape[1])]
-                pixel_spacing_out = [target_spacing, native_col_spacing]
-                spacing_between_slices_out = float(native_row_spacing)
-                image_orientation_out = [
-                    float(normal_dir[0]),
-                    float(normal_dir[1]),
-                    float(normal_dir[2]),
-                    float(col_dir[0]),
-                    float(col_dir[1]),
-                    float(col_dir[2]),
-                ]
-
-                def position_for_index(idx):
-                    return build_position(
-                        origin_ipp,
-                        row_dir,
-                        col_dir,
-                        normal_dir,
-                        row_index=idx,
-                        col_index=0,
-                        stack_offset=base_z_offset,
-                    )
-            elif plane_norm == "sagittal":
-                recon_slices = [volume_for_recon[:, :, i] for i in range(volume_for_recon.shape[2])]
-                pixel_spacing_out = [target_spacing, native_row_spacing]
-                spacing_between_slices_out = float(native_col_spacing)
-                image_orientation_out = [
-                    float(normal_dir[0]),
-                    float(normal_dir[1]),
-                    float(normal_dir[2]),
-                    float(row_dir[0]),
-                    float(row_dir[1]),
-                    float(row_dir[2]),
-                ]
-
-                def position_for_index(idx):
-                    return build_position(
-                        origin_ipp,
-                        row_dir,
-                        col_dir,
-                        normal_dir,
-                        row_index=0,
-                        col_index=idx,
-                        stack_offset=base_z_offset,
-                    )
-            else:
-                continue
-
-            recon_series = _create_series_derivative(series, f"Recon {plane_norm.title()}")
-            recon_series.series_instance_uid = generate_uid()
-            recon_series.save(update_fields=["series_instance_uid"])
-
-            for idx, arr2d in enumerate(recon_slices):
-                ds_new = copy.deepcopy(template_ds)
-                arr2d = np.asarray(arr2d, dtype=dicom_items[0][2].dtype)
-
-                ds_new.Rows = int(arr2d.shape[0])
-                ds_new.Columns = int(arr2d.shape[1])
-                ds_new.InstanceNumber = idx + 1
-                ds_new.SOPInstanceUID = generate_uid()
-                ds_new.SeriesInstanceUID = recon_series.series_instance_uid
-                ds_new.PixelData = arr2d.tobytes()
-                ds_new.PixelSpacing = [float(pixel_spacing_out[0]), float(pixel_spacing_out[1])]
-                ds_new.ImageOrientationPatient = image_orientation_out
-                ds_new.ImagePositionPatient = position_for_index(idx)
-
-                ds_new.SliceThickness = float(slab_thickness)
-                ds_new.SpacingBetweenSlices = float(spacing_between_slices_out)
-
-                out_io = io.BytesIO()
-                ds_new.save_as(out_io, write_like_original=False)
-                out_io.seek(0)
-
-                recon_image = SeriesImage(series=recon_series, position=idx + 1, upload_filename=f"recon_{plane_norm}_{idx+1}.dcm")
-                recon_image.image.save(
-                    f"recon_{plane_norm}_{recon_series.pk}_{idx+1}.dcm",
-                    ContentFile(out_io.getvalue()),
-                    save=False,
-                )
-                recon_image.save()
-
-            created_series.append(recon_series)
-
-        if not created_series:
-            return HttpResponse('<div class="alert alert-warning mb-0">No reconstruction plane could be generated.</div>')
-
-        links = " ".join(
-            [
-                f'<a class="alert-link me-2" target="_blank" href="{s.get_absolute_url()}">{escape(s.description or str(s.pk))}</a>'
-                for s in created_series
-            ]
+        async_task = series_reconstruct_task.delay(
+            series_id=series.pk,
+            user_id=request.user.pk,
+            recon_planes=recon_planes,
+            slice_thickness_val=slice_thickness_val,
+            slice_spacing_val=slice_spacing_val,
+            recon_thickness_mode=recon_thickness_mode,
         )
+
         return HttpResponse(
             (
-                '<div class="alert alert-success mb-0">'
-                f'Created <strong>{len(created_series)}</strong> reconstruction series '
-                f'(spacing={target_spacing:.2f}mm, thickness={slab_thickness:.2f}mm, mode={escape(recon_thickness_mode)}): {links}'
+                '<div class="alert alert-info mb-2">'
+                'Reconstruction queued. This runs in the background to avoid request timeout.'
                 '</div>'
+                f'<div id="recon-task-status" hx-get="{reverse("atlas:series_reconstruct_status", kwargs={"series_id": series.pk, "task_id": async_task.id})}" '
+                'hx-trigger="load, every 2s" hx-swap="outerHTML">'
+                '<div class="d-flex align-items-center gap-2"><span class="spinner-border spinner-border-sm text-primary" role="status"></span>'
+                '<span class="small text-muted">Starting reconstruction task...</span></div></div>'
             )
         )
 
     return HttpResponse('<div class="alert alert-danger mb-0">Unknown optimize operation.</div>')
 
 
+@login_required
+def series_reconstruct_status_htmx(request, series_id, task_id):
+    """HTMX endpoint returning progress for a queued series reconstruction task."""
+    series = get_object_or_404(Series, pk=series_id)
+
+    if not series.check_user_can_edit(request.user):
+        return HttpResponse('<div class="alert alert-danger mb-0">Permission denied</div>')
+
+    task_result = AsyncResult(task_id)
+    state = task_result.state
+
+    poll_url = reverse("atlas:series_reconstruct_status", kwargs={"series_id": series.pk, "task_id": task_id})
+
+    if state in ("PENDING", "STARTED", "RETRY"):
+        return HttpResponse(
+            (
+                f'<div id="recon-task-status" hx-get="{poll_url}" hx-trigger="every 2s" hx-swap="outerHTML">'
+                '<div class="d-flex align-items-center gap-2">'
+                '<span class="spinner-border spinner-border-sm text-primary" role="status"></span>'
+                '<span class="small text-muted">Reconstruction is running...</span>'
+                '</div></div>'
+            )
+        )
+
+    if state == "PROGRESS":
+        meta = task_result.info or {}
+        current = int(meta.get("current", 0) or 0)
+        total = int(meta.get("total", 0) or 0)
+        message = escape(str(meta.get("message", "Reconstruction running...")))
+        pct = int((current / total) * 100) if total > 0 else 0
+
+        return HttpResponse(
+            (
+                f'<div id="recon-task-status" hx-get="{poll_url}" hx-trigger="every 2s" hx-swap="outerHTML">'
+                f'<div class="small text-muted mb-1">{message}</div>'
+                '<div class="progress" style="height: 10px;">'
+                f'<div class="progress-bar progress-bar-striped progress-bar-animated" role="progressbar" style="width: {pct}%" '
+                f'aria-valuenow="{pct}" aria-valuemin="0" aria-valuemax="100"></div>'
+                '</div>'
+                f'<div class="small text-muted mt-1">{current}/{total} slices processed</div>'
+                '</div>'
+            )
+        )
+
+    if state == "SUCCESS":
+        payload = task_result.result if isinstance(task_result.result, dict) else {}
+        created_series = payload.get("created_series", [])
+
+        if created_series:
+            links = " ".join(
+                [
+                    f'<a class="alert-link me-2" target="_blank" href="{escape(item.get("url", "#"))}">{escape(item.get("description", str(item.get("id", "series"))))}</a>'
+                    for item in created_series
+                ]
+            )
+            return HttpResponse(
+                (
+                    '<div id="recon-task-status" class="alert alert-success mb-0">'
+                    f'Reconstruction complete. Created <strong>{len(created_series)}</strong> series: {links}'
+                    '</div>'
+                )
+            )
+
+        return HttpResponse('<div id="recon-task-status" class="alert alert-warning mb-0">Reconstruction finished but no output series were created.</div>')
+
+    if state == "FAILURE":
+        err = escape(str(task_result.result))
+        return HttpResponse(
+            f'<div id="recon-task-status" class="alert alert-danger mb-0">Reconstruction failed: {err}</div>'
+        )
+
+    return HttpResponse(
+        f'<div id="recon-task-status" class="alert alert-secondary mb-0">Task state: {escape(state)}</div>'
+    )
+
+
 @login_required
 def series_image_size_htmx(request, series_id):
     """HTMX endpoint returning the total size of images in a series.