Roweis and I spent some time working on the
tweak phase of astrometry, which follows rough determination of pointing, rotation, and scale, and which refines a close solution to a precise solution.
We also both worked on the text of paper zero, which we are drafting with a computer-science focus and in the flashy style of Science or Nature. We hope to finish and submit while we are in alpha. We still aren't in alpha, but we are very, very close (and our alpha testers are getting, well, testy).