  Polarimetry remains a largely unexploited technique in observational X-ray
astronomy which could provide insight in the study of the strong gravity and
magnetic fields at the core of the Constellation-X observational program.
Adding a polarization capability to the Constellation-X instrumentation would
be immensely powerful. It would make Constellation the first space observatory
to simultaneously measure all astrophysically relevant parameters of source
X-ray photons; their position (imaging), energy (spectroscopy), arrival time
(timing), and polarization. Astrophysical polarimetry requires sensitive
well-calibrated instruments. Many exciting objects are extra-galactic (i.e.
faint) and may have small polarization. Recent advances in efficiency and
bandpass make it attractive to consider a polarimetry Science Enhancement
Package for the Constellation-X mission.
