Data was taken with the instrument in two orientations, with rotation about the telescope optical axis.  Polarization using the VIS channel was done in two stages in order to extend the spectral range.

file         instrument orientation (degrees)         lamp               channel
polar_2c                -90.0                        halogen               vis
polar_2d                 0.0                         halogen               vis
polar_2e                 0.0                         deuterium             vis
polar_2f                 0.0                         deuterium             muv
polar_2g                -90.0                        deuterium             vis
polar_2h                -90.0                        deuterium             muv