  We parameterize the initial flux composition of high energy astrophysical
neutrinos as (Phi_e^0 : Phi_mu^0 : Phi_tau^0) = (1 : n : 0), where n
characterizes the source. All usually assumed neutrino sources appear as limits
of this simple parametrization. We investigate how precise neutrino telescopes
can pin down the value of n. We furthermore show that there is a neutrino
mixing scenario in which the ratio of muon neutrinos to the other neutrinos
takes a constant value regardless of the initial flux composition. This occurs
when the muon neutrino survival probability takes its minimal allowed value.
The phenomenological consequences of this very predictive neutrino mixing
scenario are given.
