Keep pulse profile visible if pulsar doesn't spin

src/pulsaranimationwidget.cpp

@@ -789,12 +789,15 @@ void PulsarAnimationWidget::resetParameters()
 
 void PulsarAnimationWidget::updatePulseProfile()
 {
+    // avoid division by zero (keep profile visible if pulsar doesn't spin)
+    double pulsarRotationDelta = m_pulsarRotationDelta == 0.0 ? 0.01 : m_pulsarRotationDelta;
+
     // prepare parameters (e.g. convert to radians where necessary)
     const double    i               = deg2rad * m_pulsarSpinAxisInclination;
     const double    y               = deg2rad * m_pulsarMagneticAxisInclination;
     double          phiOrb          = deg2rad * (m_orbitRotationAngle + 90.0);
     const double    deltaPhiRot     = deg2rad * 1.0;
-    const double    deltaPhiOrb     = deg2rad * deltaPhiRot * m_orbitRotationDelta / m_pulsarRotationDelta;
+    const double    deltaPhiOrb     = deg2rad * deltaPhiRot * m_orbitRotationDelta / pulsarRotationDelta;
     const double    rp              = m_pulsarSemiMajorAxis;
     const double    xk              = -m_cameraPosZ;
     const double    yk              = -m_cameraPosX;