Measurement of Seeing Induced Spurious Polarization

NAGARAJU, K.; FELLER, A.; IGLESIAS, F. A; SOLANKI, S.K.

Simposio; IAU Symposium 305: Polarimetry: From the Sun to Stars and Stellar Environments; 2014

International Astronomical Union

Ground based polarimetric observations are detrimentally affected by the rapid image distortionsintroduced by atmospheric seeing. Because of the non-simultaneous nature of the polarization measurement process, seeing causes intermixing of the Stokes vector components. This intermixing, also known as seeing induced cross-talk, has been measured as a function ofpolarization modulation frequency as well as the number of image aberration terms corrected by an adaptive optics system. The preliminary analysis of these measurements shows that while at lower modulation frequencies (≈ 2 Hz) the cross-talk decreases with increase in number of image aberration terms corrected, at higher modulation frequencies (>25 Hz) the AO corrections don?t seem to play any significant role. However, in agreement with earlier findings, there is a significant reduction in cross-talk with increase in modulation frequency.