Lang and I pair-coded all day. We can now optimize the likelihood of a new SDSS Catalog against the imaging pixels in a field, permitting the model both continuous changes (parameter updates) and qualitative changes (model type changes, like star to galaxy and so on). We find that we can enormously improve the goodness of fit and reduce greatly the number of parameters, so it is win–win. It was a great day! Now we must write, write, write.