fix wrong initialization

GUI/Model/Device/InstrumentItems.cpp

@@ -417,9 +417,9 @@ ICoordSystem* GISASInstrumentItem::createCoordSystem() const
 
 OffSpecularInstrumentItem::OffSpecularInstrumentItem()
 {
-    m_alphaAxis.initNbins("Nbins", "Number of points in scan across sample bulk");
-    m_alphaAxis.initMin("Min", "Starting value below sample horizon", -100.0, Unit::nanometer);
-    m_alphaAxis.initMax("Max", "Ending value above sample horizon", 100.0, Unit::nanometer);
+    m_alphaAxis.initNbins("Nbins", "Number of points in scan");
+    m_alphaAxis.initMin("Min", "Starting value", 0.0, Unit::degree);
+    m_alphaAxis.initMax("Max", "Ending value", 10.0, Unit::degree);
 
     auto* beam_item = dynamic_cast<GISASBeamItem*>(beamItem());
     beam_item->setInclinationAngleGetter([=]() { return m_alphaAxis.min(); });