diff --git a/tardis/analysis.py b/tardis/analysis.py
index 0bb480c2b87..e6e4d5b33c4 100644
--- a/tardis/analysis.py
+++ b/tardis/analysis.py
@@ -13,16 +13,14 @@ class LastLineInteraction(object):
     @classmethod
     def from_model(cls, model):
         return cls(model.last_line_interaction_in_id, model.last_line_interaction_out_id,
-                   model.last_line_interaction_shell_id, model.montecarlo_nu.value, model.atom_data.lines)
+                   model.last_line_interaction_shell_id, model.last_line_interaction_angstrom, model.atom_data.lines)
 
     def __init__(self, last_line_interaction_in_id, last_line_interaction_out_id, last_line_interaction_shell_id,
-                 montecarlo_nu, lines, packet_filter_mode='packet_nu'):
+                 last_line_interaction_angstrom, lines, packet_filter_mode='packet_nu'):
         self.last_line_interaction_in_id = last_line_interaction_in_id
         self.last_line_interaction_out_id = last_line_interaction_out_id
         self.last_line_interaction_shell_id = last_line_interaction_shell_id
-        self.montecarlo_nu = montecarlo_nu * u.Hz
-        self.last_line_interaction_angstrom = self.montecarlo_nu[last_line_interaction_in_id != -1].to('angstrom',
-                                                                                                       u.spectral())
+        self.last_line_interaction_angstrom = last_line_interaction_angstrom
         self.lines = lines
 
         self._wavelength_start = 0 * u.angstrom
@@ -83,6 +81,7 @@ def update_last_interaction_filter(self):
             packet_filter = (line_in_nu > self.wavelength_start.to(u.angstrom).value) & \
                 (line_in_nu < self.wavelength_end.to(u.angstrom).value)
 
+                
         self.last_line_in = self.lines.ix[self.last_line_interaction_in_id[packet_filter]]
         self.last_line_out = self.lines.ix[self.last_line_interaction_out_id[packet_filter]]
 
@@ -352,4 +351,4 @@ def get_last_line_interaction(self, iteration=-1):
             montecarlo_nu = hdf_store[model_string % 'montecarlo_nus'].values
         hdf_store.close()
         return LastLineInteraction(last_line_interaction_in_id, last_line_interaction_out_id, last_line_interaction_shell_id,
-                            montecarlo_nu, self.lines)
\ No newline at end of file
+                            montecarlo_nu, self.lines)
diff --git a/tardis/gui.py b/tardis/gui.py
index 514659fc696..0b55d3f382b 100644
--- a/tardis/gui.py
+++ b/tardis/gui.py
@@ -365,7 +365,6 @@ def on_species_clicked(self, index):
 
 
 
-
 class LineInfo(QtGui.QDialog):
 
     def __init__(self, parent, wavelength_start, wavelength_end):
@@ -375,16 +374,17 @@ def __init__(self, parent, wavelength_start, wavelength_end):
         self.setWindowTitle('Line Interaction: %.2f - %.2f (A) ' % (wavelength_start, wavelength_end,
         ))
         self.layout = QtGui.QVBoxLayout()
-        packet_nu_line_interaction = analysis.LastLineInteraction(self.parent.model, packet_filter_mode="packet_nu")
+        packet_nu_line_interaction = analysis.LastLineInteraction.from_model(self.parent.model)
+        packet_nu_line_interaction.packet_filter_mode = 'packet_nu'
         packet_nu_line_interaction.wavelength_start = wavelength_start * u.angstrom
         packet_nu_line_interaction.wavelength_end = wavelength_end * u.angstrom
-
-        line_in_nu_line_interaction = analysis.LastLineInteraction(self.parent.model, packet_filter_mode="line_in_nu")
+        
+        line_in_nu_line_interaction = analysis.LastLineInteraction.from_model(self.parent.model)
+        line_in_nu_line_interaction.packet_filter_mode = 'line_in_nu'
         line_in_nu_line_interaction.wavelength_start = wavelength_start * u.angstrom
         line_in_nu_line_interaction.wavelength_end = wavelength_end * u.angstrom
 
 
-
         self.layout.addWidget(LineInteractionTables(packet_nu_line_interaction, self.parent.model.atom_data, 'filtered by frequency of packet'))
         self.layout.addWidget(LineInteractionTables(line_in_nu_line_interaction, self.parent.model.atom_data, 'filtered by frequency of line interaction'))