Polarimeter
The SX and DX polarimeters are mounted at the direct Gregorian mount in place of the MODS instruments. The two are basically identical. The two polarimeters provide a full Stokes IQUV vector. Currently only R=130,000 is available.
The two Polarimeters are based on a classical dual-beam design with a Foster prism with two orthogonally polarized beams in parallel. A retarder in front of the Foster Prism in each beam can be inserted when circular polarization is measured and removed when linear polarization is measured. This ensures no cross-talk between the linear and circular polarization.
| Angle | |
| Stokes V | 45o, 135o |
| Foster prism for Q | 0o, 90o |
| Foster prism for U | 45o, 135o |
In polarization mode, all four fibers (target and sky) will simultaneously direct two ordinary and two extraordinary light beams to the spectrograph.
