Measure the ring span along the plane the rings lie in

The span went to `distanceRings` as the target's straight-line distance from the
Sun, but a ring of radius r passes within |r - p| of the view's centre, where p
is how far out that centre is *along* the galactic plane. For a target above the
plane the two differ by its height, so the band was centred on a radius no ring
has — and `ringLabels` picks its bearing by comparing its own in-plane distance
against the innermost ring, a comparison the new first ring quietly broke.

Two comments and a constant, from the same review. A frame short of the survey
edge gets its callout only when its last ring overshoots it: 245 pc does, 235 pc
does not, which is now a test rather than a sentence. The ring count can reach
16, not 14, now that the span need not start at the Sun. And a ring label was
measured as 135 px of star name when "50 pc" is a third of that, which rejected
rungs a hand's breadth clear of the name: RING_LABEL_REACH_NDC, 0.23, is the
widest of them — "1.5 kpc" with "Survey edge" under it.

Three mutants, three caught. Measured again in the app: unchanged for a star in
the plane (4 labels at 20 pc above it, 7 at 2 pc), and the rings now follow the
plane for one 195 pc above it rather than ringing a place the grid does not
reach.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016jxMkwA2rbicdGxHosecYi

src/app/features/galaxy-system/galaxy-system-scene.component.ts

@@ -79,6 +79,12 @@ const LABEL_EDGE_NDC = 0.7;
 const RING_LABEL_CLEARANCE_NDC = LABEL_MIN_SEPARATION_NDC / 2;
 /** How far right of its point a label's text reaches, in aspect-scaled NDC (~135px at 1440). */
 const LABEL_REACH_NDC = 0.3;
+/**
+ * The same for a ring label, which is shorter: "1.5 kpc" with "Survey edge" under it is the widest
+ * of them, about 100px at 1440. Measuring those as a star name's width rejected rungs a hand's
+ * breadth clear of it.
+ */
+const RING_LABEL_REACH_NDC = 0.23;
 /**
  * How long the range control has to be still before the graph is rebuilt at its value, since a drag
  * emits per pixel; and how often at most a view on the move gets a graph for its new drawn stars.
@@ -953,7 +959,7 @@ export class GalaxySystemSceneComponent implements AfterViewInit, OnDestroy {
         !taken.some(
           (name) =>
             name.at.distanceTo(point) < RING_LABEL_CLEARANCE_NDC ||
-            (Math.abs(name.at.y - point.y) < RING_LABEL_CLEARANCE_NDC && name.from < point.x + LABEL_REACH_NDC && point.x < name.to)
+            (Math.abs(name.at.y - point.y) < RING_LABEL_CLEARANCE_NDC && name.from < point.x + RING_LABEL_REACH_NDC && point.x < name.to)
         )
       );
     });
@@ -985,7 +991,13 @@ export class GalaxySystemSceneComponent implements AfterViewInit, OnDestroy {
       // does not contain the Sun — 20 pc rings for a view of a 19 pc band at 190 pc drew none of
       // them on screen, and the ladder of labels went with them.
       const frameRadiusPc = this.engine.visibleHalfHeight(orbitPc) * Math.hypot(1, this.viewportAspect());
-      const radii = distanceRings(Math.max(0, target.length() - frameRadiusPc), target.length() + orbitPc, LOCAL_GRID_RING_COUNT, SURVEY_EDGE_PC);
+      // Measured in the plane the rings lie in, not through it: a ring of radius r passes within
+      // `|r - p|` of the view's centre, where p is how far out the centre is *along the plane*. For
+      // a target above it the two differ by its height, which would put the band around a radius no
+      // ring has — and `ringLabels` compares its own in-plane bearing against the innermost.
+      const normal = galacticNormal();
+      const inPlanePc = target.clone().addScaledVector(normal, -target.dot(normal)).length();
+      const radii = distanceRings(Math.max(0, inPlanePc - frameRadiusPc), inPlanePc + orbitPc, LOCAL_GRID_RING_COUNT, SURVEY_EDGE_PC);
       if (radii.join() !== this.localGridRadii.join()) {
         this.setLocalGridRadii(radii);
       }