diff --git a/mirrordlg.cpp b/mirrordlg.cpp
index 95403981..21d37106 100644
--- a/mirrordlg.cpp
+++ b/mirrordlg.cpp
@@ -114,7 +114,9 @@ mirrorDlg::mirrorDlg(QWidget *parent) :
     if (m_verticalAxis == 0)
         m_verticalAxis = diameter;
     ui->ellipseShape->setChecked(m_outlineShape == ELLIPSE);
+    setEllipseControlsEnabled(m_outlineShape == ELLIPSE);
     ui->minorAxisEdit->setText(QString().number(m_verticalAxis));
+    enforceEllipseMajorAxis();
     ui->diameter->setText(QString("%1").arg(diameter, 6, 'f', 2));
     ui->obs->setText(QString("%1").arg(obs, 6, 'f', 2));
     ui->FNumber->blockSignals(false);
@@ -144,6 +146,27 @@ double mirrorDlg::getMinorAxis(){
 bool mirrorDlg::isEllipse(){
     return m_outlineShape == ELLIPSE;
 }
+
+void mirrorDlg::setEllipseControlsEnabled(bool enabled)
+{
+    ui->minorAxisEdit->setEnabled(enabled);
+}
+
+void mirrorDlg::enforceEllipseMajorAxis()
+{
+    if (m_outlineShape != ELLIPSE || diameter <= 0)
+        return;
+
+    if (m_verticalAxis > diameter){
+        const double originalVerticalAxis = m_verticalAxis;
+        m_verticalAxis = diameter;
+        const QSignalBlocker blocker(ui->minorAxisEdit);
+        ui->minorAxisEdit->setText(QString::number(m_verticalAxis));
+        spdlog::get("logger")->info("Ellipse axis clamp applied: vertical axis {} exceeded horizontal axis {}. Vertical axis was clamped to {}.",
+                                     originalVerticalAxis, diameter, m_verticalAxis);
+    }
+}
+
 void mirrorDlg::saveJson(const QString &fileName){
     QJsonObject jDoc, jMirror,jIgram, jEllipse, jAnnulus;
     jDoc["name"] = m_name;
@@ -211,6 +234,7 @@ void mirrorDlg::loadFile(QString & fileName){
 
     // clear ellipse in case this is an old config that does not have it.
     ui->ellipseShape->setChecked(false);
+    setEllipseControlsEnabled(false);
     m_outlineShape = CIRCLE;
     QFileInfo info(fileName);
     QSettings settings;
@@ -286,8 +310,10 @@ void mirrorDlg::loadFile(QString & fileName){
         ui->z8->setText(QString().number(z8));
 
         ui->ellipseShape->setChecked(m_outlineShape == ELLIPSE);
+        setEllipseControlsEnabled(m_outlineShape == ELLIPSE);
 
         ui->minorAxisEdit->setText(QString::number(m_verticalAxis));
+        enforceEllipseMajorAxis();
 
         FNumber = roc/(2. * diameter);
         ui->FNumber->blockSignals(true);
@@ -418,6 +444,7 @@ void mirrorDlg::loadFile(QString & fileName){
                 file.read(buf,4);
                 m_outlineShape = *(outlineShape*)buf;
                 ui->ellipseShape->setChecked(m_outlineShape == ELLIPSE);
+                setEllipseControlsEnabled(m_outlineShape == ELLIPSE);
 
             }
             // vertical axis
@@ -425,6 +452,7 @@ void mirrorDlg::loadFile(QString & fileName){
                 file.read(buf,8);
                 m_verticalAxis = *(double*)buf;
                 ui->minorAxisEdit->setText(QString::number(m_verticalAxis));
+                enforceEllipseMajorAxis();
             }
 
             FNumber = roc/(2. * diameter);
@@ -462,6 +490,7 @@ void mirrorDlg::on_diameter_textChanged(const QString &arg1) {
         ui->minorAxisEdit->setText(QString().number(m_verticalAxis));
     }
     diameter = diam;
+    enforceEllipseMajorAxis();
     FNumber = roc/(2. * diameter);
     ui->FNumber->blockSignals(true);
     ui->FNumber->setText(QString("%1").arg(FNumber, 6, 'f', 2));
@@ -482,6 +511,7 @@ void mirrorDlg::on_diameter_Changed(const double diam)
         ui->minorAxisEdit->setText(QString().number(m_verticalAxis));
     }
     diameter = diam ;
+    enforceEllipseMajorAxis();
     FNumber = roc/(2. * diameter);
     ui->FNumber->blockSignals(true);
     const QSignalBlocker blocker(ui->diameter);
@@ -694,11 +724,13 @@ void mirrorDlg::on_minorAxisEdit_textChanged(const QString &arg1)
 {
 
     m_verticalAxis = arg1.toDouble();
+    enforceEllipseMajorAxis();
 }
 
 void mirrorDlg::setMinorAxis(double val){
     m_verticalAxis = val;
     ui->minorAxisEdit->setText(QString::number(val));
+    enforceEllipseMajorAxis();
     //on_minorAxisEdit_textChanged( QString::number(val));
 }
 
@@ -707,10 +739,13 @@ void mirrorDlg::on_ellipseShape_clicked(bool checked)
     if (checked) m_outlineShape = ELLIPSE;
     else m_outlineShape = CIRCLE;
 
+    setEllipseControlsEnabled(checked);
+
     if (m_verticalAxis == 0){
         m_verticalAxis = diameter;
         ui->minorAxisEdit->setText(QString().number(m_verticalAxis));
     }
+    enforceEllipseMajorAxis();
 }
 
 
diff --git a/mirrordlg.h b/mirrordlg.h
index a810e1e8..38c1ce16 100644
--- a/mirrordlg.h
+++ b/mirrordlg.h
@@ -136,6 +136,8 @@ private slots:
 private:
     explicit mirrorDlg(QWidget *parent = 0);
     void setclearAp();
+    void setEllipseControlsEnabled(bool enabled);
+    void enforceEllipseMajorAxis();
 
     Ui::mirrorDlg *ui;
     bool m_aperatureReductionValueChanged;
diff --git a/surfacemanager.cpp b/surfacemanager.cpp
index 228f2e35..0203bc7b 100644
--- a/surfacemanager.cpp
+++ b/surfacemanager.cpp
@@ -1407,6 +1407,13 @@ wavefront * SurfaceManager::readWaveFront(const QString &fileName){
 
         }
     }
+
+    if (md->isEllipse() && md->m_verticalAxis > md->diameter){
+        spdlog::get("logger")->info("Wavefront load ellipse axis clamp: vertical axis {} exceeded horizontal axis {}. Vertical axis was clamped to {}.",
+                                     md->m_verticalAxis, md->diameter, md->diameter);
+        md->setMinorAxis(md->diameter);
+    }
+
     wf->diameter = diam;
     wf->roc = roc;
     wf->lambda = lambda;