I had a great visit to JHU today, with extensive conversations with JHU locals Ali-Haimoud, Wyse, Szalay, Kuntz, Menard, Tollerud, van Velzen, Nataf, and visitor Dalya Baron (TAU). With Wyse I caught up after many years (a decade?); we discussed chemical tagging, radial migration, and stellar spectroscopy. I gave a late-afternoon talk on The Cannon and its use in measuring stellar parameters in an interactive forum. I also had a great chance to talk flat-fielding with the HST calibration team, who are among the world's best calibrators.
Before all that, I did more pair coding with Price-Whelan (Princeton) on the likelihood ratios, and we had a realization: If we are looking for binary stars, we do expect finite, detectable velocity differences as the separation between the pairs of stars gets small. He implemented this before the day was out and the results look very good.