  We explore linear redshift distortions in wide angle surveys from the point
of view of symmetries. We show that the redshift space two-point correlation
function can be expanded into tripolar spherical harmonics of zero total
angular momentum $S_{l_1 l_2 l_3}(\hat x_1, \hat x_2, \hat x)$. The
coefficients of the expansion $B_{l_1 l_2 l_3}$ are analogous to the $C_l$'s of
the angular power spectrum, and express the anisotropy of the redshift space
correlation function. Moreover, only a handful of $B_{l_1 l_2 l_3}$ are
non-zero: the resulting formulae reveal a hidden simplicity comparable to
distant observer limit. The $B_{l_1 l_2 l_3}$ depend on spherical Bessel
moments of the power spectrum and $f = \Omega^{0.6}/b$. In the plane parallel
limit, the results of \cite{Kaiser1987} and \cite{Hamilton1993} are recovered.
The general formalism is used to derive useful new expressions. We present a
particularly simple trigonometric polynomial expansion, which is arguably the
most compact expression of wide angle redshift distortions. These formulae are
suitable to inversion due to the orthogonality of the basis functions. An
alternative Legendre polynomial expansion was obtained as well. This can be
shown to be equivalent to the results of \cite{SzalayEtal1998}. The simplicity
of the underlying theory will admit similar calculations for higher order
statistics as well.
