English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Context. Calibration of optical polarimeters relies on the use of stars withnegligible polarization (unpolarized standard stars) for determining theinstrumental polarization zero-point. For wide-field polarimeters, calibrationis often done by imaging the same star over multiple positions in the field ofview - a process which is time-consuming. A more effective technique is totarget fields containing multiple standard stars. While this method has beenused for fields with highly polarized stars, there are no such sky regions withwell-measured unpolarized standard stars. Aims. We aim to identify sky regionswith tens of stars exhibiting negligible polarization, which are suitable forzero-point calibration of wide-field polarimeters. Methods. We selected starsin regions with extremely low reddening, located at high Galactic latitudes. Wetargeted four ~ 400 x 400 fields in the northern, and eight in the southernEquatorial hemisphere. Observations were carried out at the SkinakasObservatory and the South African Astronomical Observatory respectively.Results. We find two fields in the North and seven in the South with meanpolarization lower than p < 0.1%. Conclusions. At least nine out of twelvefields can be used for zero-point calibration of wide-field polarimeters.

Zero-polarization candidate regions for calibration of wide-field optical polarimeters