Thanks for posting that. I'm counting 10 peaks in 4 years, or about 9 cycles in 1100 days, for an average of 120 days (4 months) between peaks. Looks like we just passed a peak. The amplitude of the cycles appears to be increasing.
Hadn't really noticed this amplitude increase until you mentioned it, now there's something interesting, I'm gonna guess it's from the red giant, maybe a hotspot, due to accretion disc brightening I suppose, which could be the start of increased mass transfer with some hysteresis on the go. Or not. The last "high state" in the twenty teens apparently hid the ellipsoidal morphology of the lightcurve, at least mostly, and memory says past amplitude in visual was around 0.4, which seems to be being exceeded.
I stared at some data myself earlier today, by coincidence, looking at recent BAA photometry database lightcurves, and it looks like the recent maximum is just beginning to tale off and the decline start. The AAVSO lightcurve generator, or more properly their data, is always too messy and ambiguous for certainty when you zoom in to small ranges of time so even though I looked at that it was all over the place. This is because a lot of photometrists claim V but aren't giving V. Yes, I know there are many alternatives to unfiltered V using V mags or visual mags for comparisions, but the primary is red and you really need proper B and V to allow for colour terms which you can get away with ignoring with non-coloured stars, but not here. B-V was ambiguous, it is either the same or shifting about 0.1, which is next to nothing. Also, I've never been sure how good even quality amateur Johnson B is because as far as I can tell you need to be up above moisture to avoid early balmer line cutoff and more observers than not are nearer to sea level or forests or urban environments.
Only safe prediction is early November 2025, as that is the same gap as between the last two outbursts. However, that's all the data there is in reality, so if it goes boom it will do so when it is ready.
As for what it has really done since the outburst, as noted elsewhere, that's not the case, as the speed of light in vacuo is a finite absolute, then no matter how fast it is, we can only talk with respect to our frame of reference. We cannot instantaneously jump to T CrB and look at the past years, we in effect see it real time, no matter how many light years distant it may be, because we can't swap from our invariant frame to its invariant frame. That's why technically when people say light from a distant object is so many years old, they are wrong, it's realtime when it hits us. Neither did it take the same number of years as light years distant to get here, as a photon in its own reference frame is moving near its maximum speed (even space has matter and magnetic fields and concentrated gravity clumps), so it has barely travelled at all. Newtons absolute here and now does not exist. I think that's how it works, anyway, but I've been wrong before, and will quite readily be wrong again.
It's in a field with several 10th and 11th magnitude stars and when it erupts to 2nd magnitude its going to look amazing! I'm going to try to get a low resolution spectrum of the red giant while the white drawf is still quiescent. When the white dwarf erupts I'd expect a _very_ different spectrum. It'll be fun trying!
