Worldwide photometry of the January 1989 Tau Persei eclipse

New UBV photoelectric photometry of τ Persei obtained at 19 different observatories during its recent January 1989 eclipse is presented. Mideclipse occurred at JD 2 447 542.31±0 d .01. The resulting light curve, though not complete at all phases, is solved for the elements with the help of two quantities derived from spectroscopy : the eclipse is 84% total at mideclipse and the ratio of the radii is 0.135 ± 0.01. Radii relative to the semimajor axis are 0.0236 for the G5 giant and 0.0032 for the A2 star. With a reasonable total mass assumed, the absolute radii say the A2 star could be luminosity class V or somewhat evolved and the G5 star is between III and II but could be closer to II.