Observed Spectrum option for the Plotly plot

tardis/visualization/tools/sdec_plot.py

@@ -1471,6 +1471,8 @@ def generate_plot_ply(
         distance : astropy.Quantity or None, optional
             Distance used to calculate flux instead of luminosity in the plot.
             It should have a length unit like m, Mpc, etc. Default value is None
+        observed_spectrum : tuple or list of two astropy quantities, optional
+            Option to plot the observed spectrum.
         show_modeled_spectrum : bool, optional
             Whether to show modeled spectrum in SDEC Plot. Default value is
             True
@@ -1547,6 +1549,32 @@ def generate_plot_ply(
                 )
             )
 
+        # Plot observed spectrum
+        if observed_spectrum:
+            observed_spectrum_wavelength = None
+            observed_spectrum_luminosity = None
+
+            if (
+                type(observed_spectrum[0]) is u.quantity.Quantity
+                and type(observed_spectrum[1]) is u.quantity.Quantity
+            ):
+                # If the observed spectrum is a list of quantities, then convert to wavelength and luminosity units
+                observed_spectrum_wavelength = observed_spectrum[0].to(u.AA)
+                observed_spectrum_luminosity = observed_spectrum[1].to(
+                    u.erg / (u.s)
+                )
+
+            else:
+                raise ValueError(
+                    "Both wavelength and luminosity should be astropy quantities."
+                )
+
+            self.fig.add_scatter(
+                x=observed_spectrum_wavelength,
+                y=observed_spectrum_luminosity,
+                name="Observed Spectrum",
+            )
+
         # Plot photosphere
         self.fig.add_trace(
             go.Scatter(