1995A&A...293..377B

High-precision longitudinal, disc-averaged magnetic field measurements have been made on two late-type stars, α CMi (HR 2943) and β Lep (HR 1829). A magneto-optical filter has been used to measure the degree of circular polarization in the wings of a line of neutral potassium (7699 A) formed in the atmosphere of the target star. From 10 nights of data taken on α CMi on the 1.9-m reflector at the South African Astronomical Observatory (SAAO) in 1993 January, an upper limit to any net longitudinal field component present - assuming the field to be constant over the period of observation - of -0.40±0.26G was established. Similarly, upper limits for β Lep of -4.3±6.4G and -0.7±1.6G were established, from 4 and 10 nights of data taken in 1992 and 1993 January respectively. No significant, periodic, day-to-day variations were seen in the three time series of data.