raw spectral data

Roweis, Blanton, and I had a lively talk about the recent Bolton & Schlegel paper on spectral data reduction. Roweis suggested a Bayesian generalization of it, the problem being, as Blanton points out, that we have to return to users what they want or expect, which might not be a posterior probability distribution over spectra! Then we moved to discussion of what Bolton & Schlegel call the matrix A. They treat this as known, but of course figuring out this matrix (which is the combined sensitivity of every pixel to every wavelength in every fiber) is really the hard part of spectroscopy.