The Simons Observatory: A fully remote controlled calibration system with a sparse wire grid for cosmic microwave background telescopes

Understand

For cosmic microwave background (CMB) polarization observations, calibration of detector polarization angles is essential.

• We have developed a fully remote controlled calibration system with a sparse wire grid that reflects linearly polarized light along the wire direction.
• The new feature is a remote-controlled system for regular calibration, which has not been possible in sparse wire grid calibrators in past experiments.
• The remote control can be achieved by two electric linear actuators that load or unload the sparse wire grid into a position centered on the optical axis of a telescope between the calibration time and CMB observation.