For polarized standard stars the pipeline determines the difference
between the measured angle and the angle tabulated in
the catalogue. Since polarization parameters are usually tabulated for
broad-band filters the pipeline selects the broad-band filter closest to
the central wavelength of the grism.
Differences may indicate problems with the zero-points of the
retarder plate angle position.
Only data with an error of less than 10 degrees in angle offset are trended.
Click on any of the plots to see a close-up version.
The latest date is indicated on top of the plot, data points belonging to that date are specially marked.
statistical averages are indicated by a solid line, and thresholds by broken lines
outliers are marked by a red asterisk. They are defined as data points outside the
"aliens" (= data points outside the plot Y limits) are marked by a red arrow (↑ or ↓)
you can download the data for each parameter set if the 'Data downloads' link shows up