diff --git a/relight/mainwindow.cpp b/relight/mainwindow.cpp
index ad4b900b..66e9f312 100644
--- a/relight/mainwindow.cpp
+++ b/relight/mainwindow.cpp
@@ -598,6 +598,7 @@ void MainWindow::newMeasure() {
 	ui->markerList->addItem(marker);
 	ui->markerList->setSelected(marker);
 	connect(marker, SIGNAL(removed()), this, SLOT(removeMeasure()));
+	connect(marker, SIGNAL(valueChanged()), this, SLOT(measureChanged()));
 	marker->startMeasure();
 }
 
@@ -639,6 +640,11 @@ void MainWindow::removeMeasure() {
 	delete marker;
 }
 
+void MainWindow::measureChanged() {
+	project.computePixelSize();
+
+}
+
 void MainWindow::removeAlign() {
 	auto marker = dynamic_cast<AlignMarker *>(QObject::sender());
 	project.aligns.erase(std::remove(project.aligns.begin(), project.aligns.end(), marker->align), project.aligns.end());
@@ -664,6 +670,7 @@ void MainWindow::setupMeasures() {
 	for(auto m: project.measures) {
 		auto marker = new MeasureMarker(m, ui->graphicsView, ui->markerList);
 		connect(marker, SIGNAL(removed()), this, SLOT(removeMeasure()));
+		connect(marker, SIGNAL(valueChanged()), this, SLOT(measureChanged()));
 		ui->markerList->addItem(marker);
 	}
 }
diff --git a/relight/mainwindow.h b/relight/mainwindow.h
index 1fe34790..c06c4c90 100644
--- a/relight/mainwindow.h
+++ b/relight/mainwindow.h
@@ -140,6 +140,7 @@ public slots:
 	void setupMeasures();
 	void newMeasure();
 	void removeMeasure();
+	void measureChanged();
 
 	void setupAligns();
 	void newAlign();
diff --git a/relight/qmeasuremarker.cpp b/relight/qmeasuremarker.cpp
index eea4ff51..ea59b39e 100644
--- a/relight/qmeasuremarker.cpp
+++ b/relight/qmeasuremarker.cpp
@@ -109,6 +109,7 @@ void MeasureMarker::askMeasure() {
 		return;
 
 	measure->length = length;
+	emit valueChanged();
 
 	if(!length) {
 	} else {
diff --git a/relight/qmeasuremarker.h b/relight/qmeasuremarker.h
index ef9d9f05..8917719a 100644
--- a/relight/qmeasuremarker.h
+++ b/relight/qmeasuremarker.h
@@ -28,6 +28,9 @@ class MeasureMarker: public Marker {
 public slots:
 	virtual void onEdit();
 
+signals:
+	void valueChanged();
+
 protected:
 	//waiting for first point, waiting for second point, all done.
 
diff --git a/src/project.cpp b/src/project.cpp
index fd162bcd..f4e7daa7 100644
--- a/src/project.cpp
+++ b/src/project.cpp
@@ -438,6 +438,7 @@ void Project::computePixelSize() {
 			count++;
 		}
 	pixelSize /= count;
+	dome.imageWidth = pixelSize * imgsize.width()/10.0; //pixel size in mm, imageWIdth in cm (ugh).
 }
 
 Sphere *Project::newSphere() {
diff --git a/src/project.h b/src/project.h
index 32796a92..4d0bace9 100644
--- a/src/project.h
+++ b/src/project.h
@@ -36,7 +36,7 @@ class Project {
 	std::vector<Align *> aligns;
 	std::vector<White *> whites;
 	QRect crop;
-	float pixelSize = 0; //if computed from measures
+	float pixelSize = 0; //if computed from measures in mm
 
 	QString name;
 	std::vector<QString> authors;