diff --git a/app/crud/attachment_point.py b/app/crud/attachment_point.py
index f58594d..b582bd5 100644
--- a/app/crud/attachment_point.py
+++ b/app/crud/attachment_point.py
@@ -2,6 +2,7 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.models.attachment_point import AttachmentPoint
+from app.models.attachment_point_name import AttachmentPointName
 
 _RELATIONSHIPS = [
     "attachment_point_name",
@@ -27,6 +28,24 @@ async def list_for_augmented_part(
     return list(result.scalars().all())
 
 
+async def list_by_augmented_parts_and_name(
+    db: AsyncSession, augmented_part_ids: list[int], name: str
+) -> list[AttachmentPoint]:
+    """AttachmentPoints named ``name`` for the given augmented parts, fetched in
+    one query."""
+    if not augmented_part_ids:
+        return []
+    result = await db.execute(
+        select(AttachmentPoint)
+        .join(AttachmentPoint.attachment_point_name)
+        .where(
+            AttachmentPoint.augmented_part_id.in_(augmented_part_ids),
+            AttachmentPointName.name == name,
+        )
+    )
+    return list(result.scalars().all())
+
+
 async def list_all(
     db: AsyncSession, skip: int = 0, limit: int = 100
 ) -> list[AttachmentPoint]:
diff --git a/app/services/scope_guide.py b/app/services/scope_guide.py
index a3f7d87..e720423 100644
--- a/app/services/scope_guide.py
+++ b/app/services/scope_guide.py
@@ -7,6 +7,7 @@ the parts of that type that fit the row's scope.
 
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.crud import attachment_point as attachment_point_crud
 from app.crud import augmented_part as augmented_part_crud
 from app.crud import fit as fit_crud
 from app.crud import part_type as part_type_crud
@@ -14,6 +15,7 @@ from app.crud import scope_info as scope_info_crud
 from app.models.fit import FitLabel
 
 SCOPE_TYPE_NAME = "Scope"
+OBJECTIVE_ATTACHMENT_POINT_NAME = "Objective"
 
 # "exact" outranks "possible" when the same part fits a scope via several fits.
 _LABEL_RANK = {FitLabel.EXACT.value: 2, FitLabel.POSSIBLE.value: 1}
@@ -43,6 +45,7 @@ async def build(
                 {
                     "scope": AugmentedPart,
                     "info": ScopeInfo | None,
+                    "objective_diameter_mm": float | None,
                     "cells": {part_type_id: [{"part": AugmentedPart, "label": str}]},
                 },
                 ...,
@@ -50,12 +53,8 @@ async def build(
         }
     """
     part_types = await part_type_crud.list_all(db, limit=1000)
-    scope_type = next(
-        (pt for pt in part_types if pt.name == SCOPE_TYPE_NAME), None
-    )
-    column_types = [
-        pt for pt in part_types if scope_type is None or pt.id != scope_type.id
-    ]
+    scope_type = next((pt for pt in part_types if pt.name == SCOPE_TYPE_NAME), None)
+    column_types = [pt for pt in part_types if scope_type is None or pt.id != scope_type.id]
 
     if scope_type is None:
         return {"column_types": column_types, "rows": []}
@@ -73,9 +72,7 @@ async def build(
     if not scope_ids:
         return {"column_types": column_types, "rows": []}
 
-    fits = await fit_crud.list_for_parts(
-        db, list(scope_ids), exclude_label=FitLabel.NONE
-    )
+    fits = await fit_crud.list_for_parts(db, list(scope_ids), exclude_label=FitLabel.NONE)
 
     # Resolve the "other" (non-scope) part on each fit in a single batched query.
     other_ids: set[int] = set()
@@ -83,20 +80,31 @@ async def build(
         scope_id, other_id = _scope_and_other(fit, scope_ids)
         if scope_id is not None and other_id not in scope_ids:
             other_ids.add(other_id)
-    other_parts = {
-        p.id: p for p in await augmented_part_crud.get_many(db, list(other_ids))
-    }
+    other_parts = {p.id: p for p in await augmented_part_crud.get_many(db, list(other_ids))}
 
     infos = {
         info.augmented_part_id: info
         for info in await scope_info_crud.list_by_augmented_parts(db, list(scope_ids))
     }
 
+    # The lens outside diameter lives on the "Objective" attachment point's
+    # StaticConnection, not on ScopeInfo (which only carries the objective
+    # *thread* spec) — see app/services/scope_import.py's column-mapping doc.
+    objective_diameters: dict[int, float] = {}
+    objective_aps = await attachment_point_crud.list_by_augmented_parts_and_name(
+        db, list(scope_ids), OBJECTIVE_ATTACHMENT_POINT_NAME
+    )
+    for ap in objective_aps:
+        if ap.static_connection is not None:
+            objective_diameters[ap.augmented_part_id] = ap.static_connection.od_mm
+        elif ap.iso_thread is not None:
+            objective_diameters[ap.augmented_part_id] = ap.iso_thread.diameter_mm
+        elif ap.unc_thread is not None:
+            objective_diameters[ap.augmented_part_id] = float(ap.unc_thread.diameter_fraction)
+
     # cell_map[scope_id][type_id][other_part_id] -> {"part", "label"}, dedup'd so a
     # part appears once per cell, keeping its strongest fit label.
-    cell_map: dict[int, dict[int, dict[int, dict]]] = {
-        sid: {} for sid in scope_ids
-    }
+    cell_map: dict[int, dict[int, dict[int, dict]]] = {sid: {} for sid in scope_ids}
     for fit in fits:
         scope_id, other_id = _scope_and_other(fit, scope_ids)
         if scope_id is None:
@@ -113,15 +121,18 @@ async def build(
     rows = []
     for scope in scopes:
         cells = {
-            type_id: sorted(
-                entries.values(), key=lambda e: e["part"].description.lower()
-            )
+            type_id: sorted(entries.values(), key=lambda e: e["part"].description.lower())
             for type_id, entries in cell_map[scope.id].items()
         }
         if fits_part_type_id is not None and fits_part_type_id not in cells:
             continue  # scope has no fit for the required accessory type
         rows.append(
-            {"scope": scope, "info": infos.get(scope.id), "cells": cells}
+            {
+                "scope": scope,
+                "info": infos.get(scope.id),
+                "objective_diameter_mm": objective_diameters.get(scope.id),
+                "cells": cells,
+            }
         )
 
     return {"column_types": column_types, "rows": rows}
diff --git a/app/templates/_scopes_table_card.html b/app/templates/_scopes_table_card.html
index dc10170..8245507 100644
--- a/app/templates/_scopes_table_card.html
+++ b/app/templates/_scopes_table_card.html
@@ -1,11 +1,17 @@
 {%- macro mag(v) -%}{{ v | int if v == v | int else v | round(1) }}{%- endmacro -%}
-{%- macro magnification(info) -%}
+{%- macro magnification_range(info) -%}
   {%- if info and info.magnification_min is not none and info.magnification_max is not none -%}
-    {{ mag(info.magnification_min) }}–{{ mag(info.magnification_max) }}×
+    {{ mag(info.magnification_min) }}-{{ mag(info.magnification_max) }}
   {%- elif info and info.magnification_min is not none -%}
-    {{ mag(info.magnification_min) }}×
+    {{ mag(info.magnification_min) }}
   {%- elif info and info.magnification_max is not none -%}
-    {{ mag(info.magnification_max) }}×
+    {{ mag(info.magnification_max) }}
+  {%- endif -%}
+{%- endmacro -%}
+{%- macro magnification(info, objective_diameter_mm) -%}
+  {%- set range = magnification_range(info) -%}
+  {%- if range -%}
+    {{ range }}x{% if objective_diameter_mm is not none %}{{ mag(objective_diameter_mm) }}{% endif %}
   {%- else -%}
     <span class="muted">—</span>
   {%- endif -%}
@@ -37,7 +43,7 @@
           <td>{{ scope.manufacturer.name if scope.manufacturer else "—" }}</td>
           <td>{{ scope.scope_model.name if scope.scope_model else "—" }}</td>
           <td>{{ scope.sub_part_type.name if scope.sub_part_type else "—" }}</td>
-          <td>{{ magnification(info) }}</td>
+          <td>{{ magnification(info, row.objective_diameter_mm) }}</td>
           <td>
             {% if info and info.objective_thread_pitch %}
               {{ info.objective_thread_pitch }}
diff --git a/tests/test_scope_guide.py b/tests/test_scope_guide.py
index 88d8361..d9f43c4 100644
--- a/tests/test_scope_guide.py
+++ b/tests/test_scope_guide.py
@@ -1,9 +1,12 @@
 import pytest
 
+from app.models.attachment_point import AttachmentPoint
+from app.models.attachment_point_name import AttachmentPointName
 from app.models.augmented_part import AugmentedPart
 from app.models.fit import Fit, FitLabel
 from app.models.part_type import PartType
 from app.models.scope_info import ScopeInfo
+from app.models.static_connection import StaticConnection
 from app.models.sub_part_type import SubPartType
 from app.services import scope_guide
 
@@ -199,7 +202,54 @@ async def test_scopes_page_renders_rows_and_fits(
     assert "Flip cover 50mm" in body  # a matching part in a fit column
     assert "fit-badge-exact" in body  # the exact fit badge
     assert "M52x0.75" in body  # scope info: objective thread
-    assert "3–18×" in body  # magnification range, integral values un-padded
+    assert "3-18" in body  # magnification range, integral values un-padded
+
+
+@pytest.mark.asyncio
+async def test_build_includes_objective_diameter(db_sessionmaker):
+    async with db_sessionmaker() as db:
+        ids = await _seed_guide_data(db)
+        apn = AttachmentPointName(name="Objective")
+        db.add(apn)
+        await db.flush()
+        db.add(
+            AttachmentPoint(
+                augmented_part_id=ids["s1"].id,
+                attachment_point_name_id=apn.id,
+                static_connection=StaticConnection(od_mm=50, od_in=1.9685),
+            )
+        )
+        await db.commit()
+
+        guide = await scope_guide.build(db)
+
+    rows = {r["scope"].description: r for r in guide["rows"]}
+    assert rows["Alpha 3-18x50"]["objective_diameter_mm"] == 50
+    assert rows["Zeta 1-6x24"]["objective_diameter_mm"] is None
+
+
+@pytest.mark.asyncio
+async def test_scopes_page_renders_objective_diameter_in_magnification(
+    client, seeded, make_user, db_sessionmaker
+):
+    async with db_sessionmaker() as db:
+        ids = await _seed_guide_data(db)
+        apn = AttachmentPointName(name="Objective")
+        db.add(apn)
+        await db.flush()
+        db.add(
+            AttachmentPoint(
+                augmented_part_id=ids["s1"].id,
+                attachment_point_name_id=apn.id,
+                static_connection=StaticConnection(od_mm=50, od_in=1.9685),
+            )
+        )
+        await db.commit()
+    await make_user("reader4@example.com", role_ids=[seeded["roles"]["user"].id])
+    await _web_login(client, "reader4@example.com")
+    resp = await client.get("/scopes")
+    assert resp.status_code == 200
+    assert "3-18x50" in resp.text
 
 
 @pytest.mark.asyncio