diff --git a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java
index 5726e6027f9..876b24f4a41 100644
--- a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java
+++ b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java
@@ -77,17 +77,16 @@ class GeoExactCircle extends GeoBaseCircle {
     final GeoPoint eastPoint = planetModel.surfacePointOnBearing(center, cutoffAngle, Math.PI * 0.5);
     final GeoPoint westPoint = planetModel.surfacePointOnBearing(center, cutoffAngle, Math.PI * 1.5);
 
-    final boolean mustSplit = cutoffAngle > Math.PI * 0.5;
     final GeoPoint edgePoint;
     if (planetModel.c > planetModel.ab) {
       // z can be greater than x or y, so ellipse is longer in height than width
-      slices.add(new ApproximationSlice(center, eastPoint, Math.PI * 0.5, westPoint, Math.PI * -0.5, northPoint, 0.0, mustSplit));
-      slices.add(new ApproximationSlice(center, westPoint, Math.PI * 1.5, eastPoint, Math.PI * 0.5, southPoint, Math.PI, mustSplit));
+      slices.add(new ApproximationSlice(center, eastPoint, Math.PI * 0.5, westPoint, Math.PI * -0.5, northPoint, 0.0, true));
+      slices.add(new ApproximationSlice(center, westPoint, Math.PI * 1.5, eastPoint, Math.PI * 0.5, southPoint, Math.PI, true));
       edgePoint = eastPoint;
     } else {
       // z will be less than x or y, so ellipse is shorter than it is tall
-      slices.add(new ApproximationSlice(center, northPoint, 0.0, southPoint, Math.PI, eastPoint, Math.PI * 0.5, mustSplit));
-      slices.add(new ApproximationSlice(center, southPoint, Math.PI, northPoint, Math.PI * 2.0, westPoint, Math.PI * 1.5, mustSplit));
+      slices.add(new ApproximationSlice(center, northPoint, 0.0, southPoint, Math.PI, eastPoint, Math.PI * 0.5, true));
+      slices.add(new ApproximationSlice(center, southPoint, Math.PI, northPoint, Math.PI * 2.0, westPoint, Math.PI * 1.5, true));
       edgePoint = northPoint;
     }
     //System.out.println("Edgepoint = " + edgePoint);
@@ -283,8 +282,10 @@ class GeoExactCircle extends GeoBaseCircle {
       if (this.plane == null) {
         throw new IllegalArgumentException("Either circle is too small or accuracy is too high; could not construct a plane with endPoint1="+endPoint1+" bearing "+point1Bearing+", endPoint2="+endPoint2+" bearing "+point2Bearing+", middle="+middlePoint+" bearing "+middlePointBearing);
       }
-      if (plane.isWithin(center) == false || !plane.evaluateIsZero(endPoint1) || !plane.evaluateIsZero(endPoint2) || !plane.evaluateIsZero(middlePoint))
-        throw new IllegalStateException("SidedPlane constructor built a bad plane!!");
+      if (this.plane.isWithin(-center.x, -center.y, -center.z)) {
+        //Plane is bogus, we cannot build the circle
+        throw new IllegalArgumentException("Could not construct a valid plane for this planet model with endPoint1="+endPoint1+" bearing "+point1Bearing+", endPoint2="+endPoint2+" bearing "+point2Bearing+", middle="+middlePoint+" bearing "+middlePointBearing);
+      }
     }
 
     @Override
diff --git a/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoExactCircleTest.java b/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoExactCircleTest.java
index 2f758f1169a..6f962142cd7 100644
--- a/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoExactCircleTest.java
+++ b/lucene/spatial3d/src/test/org/apache/lucene/spatial3d/geom/GeoExactCircleTest.java
@@ -54,8 +54,6 @@ public class GeoExactCircleTest extends RandomGeo3dShapeGenerator{
 
   @Test
   public void testSurfacePointOnBearingScale(){
-    double ab = 1.6;
-    double c = 0.7;
     PlanetModel p1 = PlanetModel.WGS84;
     PlanetModel p2 = new PlanetModel(0.5 * PlanetModel.WGS84.ab, 0.5 * PlanetModel.WGS84.c );
     GeoPoint point1P1 = new GeoPoint(p1, 0, 0);
@@ -93,9 +91,18 @@ public class GeoExactCircleTest extends RandomGeo3dShapeGenerator{
   @Test
   @Repeat(iterations = 100)
   public void RandomPointBearingCardinalTest(){
-    double ab = random().nextDouble() * 0.6 + 0.9;
-    double c = random().nextDouble() * 0.6  + 0.9 ;
-    PlanetModel planetModel = new PlanetModel(ab, c);
+    //surface distance calculations methods start not converging when
+    //planet flattening > 0.4
+    PlanetModel planetModel;
+    do {
+      double ab = random().nextDouble() * 2;
+      double c = random().nextDouble() * 2;
+      if (random().nextBoolean()) {
+        planetModel = new PlanetModel(ab, c);
+      } else {
+        planetModel = new PlanetModel(c, ab);
+      }
+    } while (Math.abs(planetModel.flattening) > 0.4);
     GeoPoint center = randomGeoPoint(planetModel);
     double radius =  random().nextDouble() * 0.9 * Math.PI;
     checkBearingPoint(planetModel, center, radius, 0);
@@ -133,7 +140,7 @@ public class GeoExactCircleTest extends RandomGeo3dShapeGenerator{
   public void exactCircleLargeTest(){
     boolean success = true;
     try {
-      GeoCircle circle = GeoCircleFactory.makeExactGeoCircle(new PlanetModel(0.5, 0.7), 0.25 * Math.PI,  0,0.35 * Math.PI, 1e-12);
+      GeoCircle circle = GeoCircleFactory.makeExactGeoCircle(new PlanetModel(0.99, 1.05), 0.25 * Math.PI,  0,0.35 * Math.PI, 1e-12);
     } catch (IllegalArgumentException e) {
       success = false;
     }
@@ -174,8 +181,8 @@ public class GeoExactCircleTest extends RandomGeo3dShapeGenerator{
    */
   @Test
   @Repeat(iterations = 100)
-  public void testRandom_LUCENE8054() {
-    PlanetModel planetModel = PlanetModel.WGS84;
+  public void testRandomLUCENE8054() {
+    PlanetModel planetModel = randomPlanetModel();
     GeoCircle circle1 = (GeoCircle) randomGeoAreaShape(EXACT_CIRCLE, planetModel);
     // new radius, a bit smaller than the generated one!
     double radius = circle1.getRadius() *  (1 - 0.01 * random().nextDouble());
@@ -232,4 +239,15 @@ public class GeoExactCircleTest extends RandomGeo3dShapeGenerator{
     assertTrue(circle1.getRelationship(circle2) != GeoArea.DISJOINT);
   }
 
+  public void testLUCENE8080() {
+    PlanetModel planetModel = new PlanetModel(1.6304230055804751, 1.0199671157571204);
+    boolean fail = false;
+    try {
+      GeoCircle circle = GeoCircleFactory.makeExactGeoCircle(planetModel, 0.8853814403571284, 0.9784990176851283, 0.9071033527030907, 1e-11);
+    } catch (IllegalArgumentException e) {
+      fail = true;
+    }
+    assertTrue(fail);
+  }
+
 }