5d transition metal oxides host complex states combining electronic correlations, crystal electric fields and spin-orbit coupling on a similar energy scale. This delicate balance has excited theoretical interest, leading to predictions of topologically non-trivial band structures in the bulk (Weyl semimetal), novel quasiparticles (Majorana fermions) and superconductivity. In 5d TMOs of the pyrochlore structure, magnetic frustration adds to the complexity of the electronic ground state. We here propose the first in-depth study of rare earth pyrochlore osmates. We will determine the ordering of the osmium magnetic moments in Y2Os2O7 below 50 K. This will form an invaluable reference for a number of future projects, including first principles calculations, inelastic studies and characterisation of other pyrochlore rare earth osmates.