A multimode configurable imaging spectropolarimeter comprising: a first beamsplitter configured to split incident electromagnetic radiation from a scene into a first optical path and a second optical path; a movable first mirror positioned in the first optical path and configured to reflect electromagnetic radiation in the first optical path, the first mirror being movable over a first scan range to provide a first optical path length difference between the first optical path and the second optical path; at least one focal plane array sensor (610, 615) configured to receive electromagnetic radiation from the first and second optical paths and characterized by: a polarizing beamsplitter (450, 810) positioned in the second optical path and configured to split electromagnetic radiation in the second optical path into a first polarization and a second polarization, the first and second polarizations being orthogonal to one another; and a movable second mirror positioned in the second optical path and configured to reflect the first polarization, the second mirror being selectively movable over a second scan range to provide a second optical path length difference between the first and second polarizations; wherein the at least one focal plane array sensor (610, 615) is configured to produce a first interferogram corresponding to the first polarization and a second interferogram corresponding to the second polarization and superimposed on the first interferogram, with a frequency offset between the first and second superimposed interferograms, wherein the multimode configurable imaging spectropolarimeter is configurable between a spectral imaging mode and a spectropolarimetric imaging mode, wherein: movement of the movable second first mirror can be deactivated to configure the imaging transform spectrometer into the spectral imaging mode, and movement of the movable second mirror can be activated to configure the imaging transform spectrometer into the spectropolarimetric imaging mode. a first beamsplitter configured to split incident electromagnetic radiation from a scene into a first optical path and a second optical path; a movable first mirror positioned in the first optical path and configured to reflect electromagnetic radiation in the first optical path, the first mirror being movable over a first scan range to provide a first optical path length difference between the first optical path and the second optical path; at least one focal plane array sensor (610, 615) configured to receive electromagnetic radiation from the first and second optical paths and characterized by: a polarizing beamsplitter (450, 810) positioned in the second optical path and configured to split electromagnetic radiation in the second optical path into a first polarization and a second polarization, the first and second polarizations being orthogonal to one another; and a movable second mirror positioned in the second optical path and configured to reflect the first polarization, the second mirror being selectively movable over a second scan range to provide a second optical path length difference between the first and second polarizations; wherein a polarizing beamsplitter (450, 810) positioned in the second optical path and configured to split electromagnetic radiation in the second optical path into a first polarization and a second polarization, the first and second polarizations being orthogonal to one another; and a movable second mirror positioned in the second optical path and configured to reflect the first polarization, the second mirror being selectively movable over a second scan range to provide a second optical path length difference between the first and second polarizations; wherein the at least one focal plane array sensor (610, 615) is configured to produce a first interferogram corresponding to the first polarization and a second interferogram corresponding to the second polarization and superimposed on the first interferogram, with a frequency offset between the first and second superimposed interferograms, wherein the multimode configurable imaging spectropolarimeter is configurable between a spectral imaging mode and a spectropolarimetric imaging mode, wherein: movement of the movable second first mirror can be deactivated to configure the imaging transform spectrometer into the spectral imaging mode, and movement of the movable second mirror can be activated to configure the imaging transform spectrometer into the spectropolarimetric imaging mode. movement of the movable second first mirror can be deactivated to configure the imaging transform spectrometer into the spectral imaging mode, and movement of the movable second mirror can be activated to configure the imaging transform spectrometer into the spectropolarimetric imaging mode.