  We present a new analysis on how to distinguish between isotropic and
anisotropic cosmological models based on tracking the angular displacements of
a large number of distant quasars over an extended period of time, and then
performing a multipole-vector decomposition of the resulting displacement maps.
We find that while the GAIA mission operating at its nominal specifications
does not have sufficient angular resolution to resolve anisotropic universes
from isotropic ones using this method within a reasonable timespan of ten
years, a next-generation GAIA-like survey with a resolution ten times better
should be equal to the task. Distinguishing between different anisotropic
models is however more demanding. Keeping the observational timespan to ten
years, we find that the angular resolution of the survey will need to be of
order 0.1 micro-arcsecond in order for certain rotating anisotropic models to
produce a detectable signature that is also unique to models of this class.
However, should such a detection become possible, it would immediately allow us
to rule out large local void models.

Cosmology and Nongalactic Astrophysics