The WALOP polarimeters

Polarimetry, as the name suggests, is the science of measuring the light's polarization. The degree of polarization (DOP or p) measures the portion of light that is polarized. Based on this measure, light can be perfectly polarized (p =100%), partially polarized (0% ≤ p ≤ 100%) or unpolarized (p = 0%).

Polarimetry with PASIPHAE will be achieved using 2 cutting-edge-technology polarimeters named WALOPs (Wide Area Linear Optical Polarimeters). One will be installed at the Skinakas 1.3 m telescope and the other at SAAO's 1m telescope. Both will have a field of view of 30 × 30 arcminutes and will be able to measure polarization of stars brighter than R=16.5 magnitude with a sensitivity in p of ≤ 0.1%.

The instruments are currently under construction in IUCAA. The optical design is being carried-out by the PhD students John Andrew Kypriotakis and Siddharth Maharana, mostly using the ZEMAX platform. The same students are running lab tests on the optical elements, to ensure the quality of the instruments. The electronics controller to be used is the IUCAA's IDSAC controller. The expected delivery period for the instruments is the final trimester of 2020.

Following images are the optical and mechanical design of the instruments appearance:

Optical design of PASIPHAE's WALOP-North instrument.





Mechanical design of PASIPHAE's WALOP-North instrument.





Optical design of PASIPHAE's WALOP-South instrument.





Mechanical design of PASIPHAE's WALOP-South instrument.


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