First-light imaging polarimetry of auroral emissions with the Polaribotn camera

Abstract. We present first-light observations of auroral imaging polarimetry with the Polaribotn camera, a monochrome micropolarizer-based instrument equipped with narrowband filtering at the O(¹S) 557.7 nm green line. The instrument was operated simultaneously with the Corbel Cru polarimeter during a campaign in Skibotn, Norway, allowing a direct comparison with the existing narrow-field reference framework. The common field of view was identified empirically from the intensity time series, and the Polaribotn measurements show good agreement with Corbel Cru in both degree and angle of linear polarization. Extending the analysis to 63 regions of interest across the full image reveals that DoLP and AoLP do not respond in the same way to auroral structures: DoLP decreases in the brightest arc regions, whereas AoLP often remains coherent over a large fraction of the field of view. The corresponding (q,u) analysis points to a strong scene-wide polarization component with local intensity-dependent perturbations. Although the present dataset does not yet allow a definitive interpretation of the physical origin of the polarization, it demonstrates that auroral imaging polarimetry is feasible and provides spatial information not accessible to previous narrow-field instruments.