=== modified file src/core/StelAppGraphicsWidget.cpp
--- src/core/StelAppGraphicsWidget.cpp	2012-01-11 10:50:37 +0000
+++ src/core/StelAppGraphicsWidget.cpp	2013-04-16 20:48:31 +0000
@@ -222,8 +222,10 @@
 	Q_ASSERT(QGLFramebufferObject::hasOpenGLFramebufferObjects());
 	if (!backgroundBuffer)
 	{
-		backgroundBuffer = new QGLFramebufferObject(scene()->sceneRect().size().toSize(), QGLFramebufferObject::CombinedDepthStencil);
-		foregroundBuffer = new QGLFramebufferObject(scene()->sceneRect().size().toSize(), QGLFramebufferObject::CombinedDepthStencil);
+		QSize size = scene()->sceneRect().size().toSize();
+		size.setHeight(size.width());
+		backgroundBuffer = new QGLFramebufferObject(size, QGLFramebufferObject::CombinedDepthStencil);
+		foregroundBuffer = new QGLFramebufferObject(size, QGLFramebufferObject::CombinedDepthStencil);
 		Q_ASSERT(backgroundBuffer->isValid());
 		Q_ASSERT(foregroundBuffer->isValid());
 	}