  We discuss the possibility to probe leptonic mixing parameters at high-energy
neutrino telescopes in a model-independent way, using astrophysical neutron and
pion sources. In particular we show how the octant of the 2-3 mixing angle
might be determined independently of prior knowledge of the source, even when
current uncertainties on the other mixing parameters are included. We also
argue that non-trivial neutrino oscillation effects should be taken into
account when using high-energy flavor ratios for astrophysical diagnostics.
