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The spectrum of T CrB at visible wavelengths is dominated by the red giant star with light from the material being transferred to the white dwarf via an accretion disc superimposed on it  (A hot blue continuum with emission lines). The left figure shows the current spectrum with the spectrum of a standard M3 giant star shown in red below it.  By subtracting the red giant spectrum (right figure) we can see the spectrum of the accretion disc more clearly. The He II 4686 line in particular is considered a proxy for accretion from the inner disc onto the white dwarf (Munari et al 2025). A comparison between the current spectrum and a spectrum taken using the same equipment in March 2024 when activity was low shows an increase in the continuum toward the blue and much increased emission line strength.  (The drop in activity from ~mid 2023 was considered to be a precursor to a nova outburst, based on what happened prior to the 1946 outburst but that did not occur and since around ~mid 2024, activity started to increase again, initially sporadically but more settled in recent months)

Observing T CrB for me is currently a race between darkness and approaching trees. As it gets dark a little earlier perhaps the trees will be kept at bay a little longer !

All spectra in the BAA and ARAS databases