spectroscopic target selection

Among other things, Morad, Blanton, and I discussed how one selects sources for spectroscopy with a spectrograph that has physical constraints on how close any two sources can be and get spectra. The desideratum is that we be able to extract nonetheless the correlation function on all scales, including those smaller than that corresponding to the mechanical constraint (as Morad has done for SDSS). We discussed two schemes, both of which involve random sparse-sampling of the sources in collision groups, ie, groups of objects that are connected by friends-of-friends with a linking length equal to the mechanical constraint.