The highlight of my research day was a long conversation with Adam J. Wheeler (Columbia) about error propagation in The Cannon. He and I discussed various ways to propagate uncertainties, which come jointly from the noisy spectra and the noisy labels that are used in the training step. There are more and more brutal approximations. We had this discussion in the context of a graphical model, which Adam (completely independently of me) had drawn just like mine. I ended up proposing that he take a jackknife approach. However, it might be possible to go fully Bayesian, something I didn't think was possible a year or two ago.
We also discussed my crazy idea to build a fully non-parametric but always locally linear version of The Cannon. This would have great properties, especially as regards noise propagation and inference.
Okay, another amazing thing about the day: In Stars and Exoplanets Meeting at Flatiron, John Brewer (Yale) showed us some brand-new data from the EXPRES spectrograph for making extreme-precision radial-velocity measurements. He showed two stars that look like they are showing empirical scatter (away from a Kepler curve) of roughly 0.4 m/s. That would be ground-breaking precision and an incredibly good start for this important new instrument. Now I have to find a way to worm my way onto that team...?
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