Point (a.) was suggested to apply to the PSF estimation, in which context it was found to be very difficult to escape single-scan orientation, since the seeing is expected to vary over time scales of the same order as a scan. Furthermore, the scan processing order is essentially random because the design takes advantage of the processing of all calibration scans before any survey scans, and several scans will generally be processed simultaneously on different CPUs and/or machines, making it impossible for one survey scan to depend on any other survey scan's estimate of the PSF (or other parameter). In the case of the PSF, a time history is to be generated in 2MAPPS, so the processing runs after the first could take advantage of previous runs' PSF estimates. It was also noted that scan-to-scan nonuniformities always appear terrifying to science teams but tend to go unnoticed by users, the IRAS ecliptic latitude dependence of position accuracy (primarily in single-band sources) being an outstanding example (apparently no user ever mentioned this well documented and unavoidable effect caused by sun-locked scanning).
Point (b.) was questioned, but its expected reduction of CPU time was said to make it worth whatever (expectedly small) impact it may have on completeness.
T. Jarrett reported that the galaxy processor is now ready for integration into the protopipeline.
G. Kopan is currently developing the STATS subsystem, from which he will extract code to estimate a seeing parameter to be used by KAMPhot to select one of the PSF models. The parameter and its relation to KAMPhot PSF models will be obtained via simulation of a constant scan observed with variable seeing. KAMPhot will construct a PSF model for each seeing level, and these will be compared to the Moffat-blurred real PSF models to determine which are the most similar and what the corresponding values of the seeing parameter are. Assuming acceptable relationships can be obtained (i.e., a pairing of members from the two sequences of PSF models can be determined), then KAMPhot can be made to use the seeing parameter to select a Moffat-blurred real PSF model, thus obtaining a scan-dependent PSF model. This is the level of time dependence sought for the April run, and the exercise should contribute to our understanding of how to handle seeing in 2MAPPS.