CC-POL Components: Calibration
Polarization efficiency can be checked with the use of a wire grid to produce pre-determined degree of polarization
Zero polarised standards can be observed to investigate instrumental polarisation (study in progress by Kidger et al)
- Field rotation facilitates instrumental polarisation subtraction
Standards of well determined degree of polarisation and PA can be observed to make PA calibration (Martin-Luis et al)
All calibrations required to be quick and easy to make
- Deployment of wire grid polariser should be under computer control
Instrumental polarisation minimized by maintaining cleanliness of all GTC reflecting surfaces.
- Each 45 degree reflection introduces 0.5% at NIR, much less at MIR wavelengths but dependent on the reflecting surface. Removable in data reduction