  The disk-integrated reflected brightness of an exoplanet changes as a
function of time due to orbital and rotational motion coupled with an
inhomogeneous albedo map. We have previously derived analytic reflected
lightcurves for spherical harmonic albedo maps in the special case of a
synchronously-rotating planet on an edge-on orbit (Cowan, Fuentes & Haggard
2013). In this paper, we present analytic reflected lightcurves for the general
case of a planet on an inclined orbit, with arbitrary spin period and non-zero
obliquity. We do so for two different albedo basis maps: bright points
($\delta$-maps), and spherical harmonics ($Y_l^m$-maps). In particular, we use
Wigner $D$-matrices to express an harmonic lightcurve for an arbitrary viewing
geometry as a non-linear combination of harmonic lightcurves for the simpler
edge-on, synchronously rotating geometry. These solutions will enable future
exploration of the degeneracies and information content of reflected
lightcurves, as well as fast calculation of lightcurves for mapping exoplanets
based on time-resolved photometry. To these ends we make available Exoplanet
Analytic Reflected Lightcurves (EARL), a simple open-source code that allows
rapid computation of reflected lightcurves.
