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Classical novae are eruptions on the surface of a white dwarf in a binarysystem. The material ejected from the white dwarf surface generally forms anaxisymmetric shell of gas and dust around the system. The three-dimensionalstructure of these shells is difficult to untangle when viewed on the plane ofthe sky. In this work a geometrical model is developed to explain newobservations of the 2015 nova V5668 Sagittarii. To understand the ionisationstructure in terms of the nova shell morphology and estimate the emissiondistribution directly following the light-curve's dust-dip.  High-cadence optical polarimetry and spectroscopy observations of a nova arepresented. The ejecta is modelled in terms of morpho-kinematics andphotoionisation structure.  Initially observational results are presented, including broadbandpolarimetry and spectroscopy of V5668 Sgr nova during eruption. Variabilityover these observations provides clues towards the evolving structure of thenova shell. The position angle of the shell is derived from polarimetry, whichis attributed to scattering from small dust grains. Shocks in the nova outfloware suggested in the photometry and the effect of these on the nova shell areillustrated with various physical diagnostics. Changes in density andtemperature as the super soft source phase of the nova began are discussed. Gasdensities are found to be of the order of 10$^{9}$ cm$^{-3}$ for the nova inits auroral phase. The blackbody temperature of the central stellar system isestimated to be around $2.2\times10^{5}$ K at times coincident with the supersoft source turn-on. It was found that the blend around 4640 $\rm{\AA}$commonly called `nitrogen flaring' is more naturally explained as flaring ofthe O~{\sc ii} multiplet (V1) from 4638 - 4696 $\rm{\AA}$, i.e. `oxygenflaring'.

Polarimetry and Spectroscopy of the `Oxygen Flaring' DQ Herculis-like nova: V5668 Sagittarii (2015)