hstpolima: Reduce linear polarization data for HST instruments (currently FOC, NICMOS and WFPC2 are supported). A set of well-aligned input images is required and the corresponding statistical error images. Images for the three Stokes parameters (I,Q and U), the linear polarization and position angle and their error images are output.
hstpolpoints: Reduce linear polarization data for HST instruments for a set of circular apertures. From a set of input images and the error frames, the linear polarization results (and errors) are returned as an STSDAS table.
hstpolsim: Produce simulated polarization input data frames for HST instruments from images of the total signal, the linear polarization and the position angle of the polarization vectors. The output images can have noise added. Images of the statistical errors are also produced for full compatibility with the input required by hstpolima.
polimodel: Produce model linear polarization and position angle images given a total signal image. The polarization variation is specified by a power law and the position angles are oriented at right angles to the direction to the centre. Random noise variations in polarization and position angle can also be included.
polimplot: Plot a polarization vector map with flexible control over vectors and labeling. Linear polarization and position angle images are required. A vector map can be over-plotted on the total signal image. Figure 2 shows an example.
There is a web page http://www.stecf.org/software/impol/ briefly describing the package and giving example polarization maps for HST and model data. A directory of demos is also available allowing simulated data with FOC, NICMOS and WFPC2 and a non-HST instrument to be produced for a model bipolar reflection nebula.