SIMBAD references

We present an analysis of polarimetric observations of standard stars performed over the period of more than 3 yr with the RINGO3 polarimeter mounted on the Liverpool Telescope. The main objective was to determine the instrumental polarization of the RINGO3 polarimeter in three spectral energy ranges: blue (350-640 nm), green (650-760 nm) and red (770-1000 nm). The observations were conducted between 2012 and 2016. The total time span of 1126 d was split into five epochs due to the hardware changes to the observing system. Our results should be applied to calibrate all polarimetric observations performed with the RINGO3 polarimeter.