Phase angle dependence of the reduced V magnitudes of 2001 QJ₁₄₂. Observations from the MPC database are also plotted with different markers depending on the MPC code after magnitude conversions (see the main text for details). Mean reduced V-band magnitudes with Seimei/TriCCS are presented as stars. (a) All magnitudes in the MPC database (except for those without filter information) plotted along with those determined from Seimei/TriCCS data. Bars indicate the 1σ uncertainties. (b) All magnitudes obtained on the same day at the same site, averaged. The fitting model curve with the H-G model is shown as a dashed line. The light curve amplitude with a period of 623.8 s, 0.43 mag, is indicated.