I spent the day commenting on papers by various co-authors. Over coffee, Eric Bell got onto the subject of orthogonal charge transfer, which is one of the methods by which PanSTARRS is going to maintain good image quality. In OCT, the idea is to monitor bright stars on short timescales, and shift the charge on the CCD east, west, north, or south as the point-spread function shifts, to keep the light falling in the most compact PSF possible. This technology has been developed and tested well at Hawaii. I got interested, because it is a perfect problem (if and how to move the charge, when) to cast into the form of Bayesian decision theory, one of my current pet methodologies.