Notes. First column gives the UT date at the beginning of each observing night. Heliocentric Julian Dates (HJD) at mid-exposure for each observed Stokes parameter are given in Cols. 2–4. Mean phase, , and the maximum difference, δϕ, between and phases of individual Stokes parameter observations are presented in Cols. 5, 6. Rotational phases were calculated according to our improved ephemeris (Sect. 4.1). The range of the S/N for each group of Stokes parameter observations taken during one night is given in Col. 7. The median S/N for each individual Stokes parameter observation are presented in Cols. 8–10. The median S/N was calculated using several echelle orders around λ = 5500 Å, where maximum counts were reached.