Schiminovich and I spent the morning working on UV background stuff; coding and testing our marginalized likelihood formalism for the mean-SED-fitting of quasars as a function of redshift. Over lunch, we discussed the information content in an astronomical image or project. I have a general formalism for computing this (it is related to the image modeling I have been doing with Lang), but haven't written it up yet. The upshot of any serious consideration of the problem is that any new image brings very little new information about quantities of interest; science moves forward on the basis of very small changes in our information content about the world. One example is that the WMAP project has had huge impact while only providing a few bits of information about the cosmological parameters! Many in the next generation of projects work in the time domain. Will the information provided justify the costs? In some sense I am betting it will, but given how little has been done in the time domain, we don't really know.
The information content of a dataset depends on what variables you count as interesting (information *about* what?). WMAP provided a few bits about cosmological parameters, but many megabits about its own images. Just goes to show how pervasive nuisance parameters are.
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