epoch.net, huge galaxies

Barron and I spent the morning arguing about his project to automatically determine the date at which an image is taken, using only the information in the image pixels themselves. Most people (okay, not most people, but maybe most astronomers) laugh when you even suggest this, but it turns out that for typical historical plates, there often is enough information in the moving stars in the image to pinpoint the date to within years. It is straightforward to define a scalar to optimize; the optimum gives you the date. It is non-trivial to determine the uncertainty on that estimate of the date. By the end of the day, Barron had a promising estimate of the error bar. Time to write!

I spent the evening frantically preparing materials to talk about huge galaxies in the Sloan Digital Sky Survey at the collaboration meeting at Fermilab tomorrow. Thanks, Blanton!