PlanetSlicer: Orange-slice algorithm for fitting brightness maps to phase curves

PlanetSlicer fits brightness maps to phase curves using the "orange-slice" method and works both for self-luminous objects and those that diffuse reflected light assuming Lambertian reflectance. In both cases, the model supposes that a spherical object can be divided into slices of constant brightness (or albedo) which may be integrated to yield the total flux observed, given the angles of observation. The package contains two key functions: toPhaseCurve and fromPhaseCurve; the former integrates the brightness for each slice to calculate the observed total flux from the object, given the longitude of observation. The latter does the opposite, estimating the brightness of the slices from a set of observed total flux (the phase curve).