Fundamental observables in galaxy clustering analysis

We propose to determine the truly observed two-point statistics from observations, either in terms of the angular power spectra, or in terms of the angle and z-dependent correlations functions. This information can be used, e.g., to constrain cosmological parameters via an Alcock-Paczinski test, or to test GR. Future surveys like Euclid will be sufficiently large to profit maximally from this cleaner cut between observations and modeling.