Photoelectric photometry of asteroids 45, 120, 776, 804, 814, and 1982DV

Photoelectric lightcurves of six asteroids, observed at the ESO 50-cm photometric telescope, are presented. 45 Eugenia, observed for pole determination program, showed a small amplitude of light variation, i.e., about 0.09÷0.10 mag. For 120 Lachesis, no period of rotation was deduced from three observing nights; it is probably longer than 20 hr. 776 Berbericia was observed again to eliminate the ambiguity between 23^h and 15^h.3 periods, as pointed out by Schober (1979). The longer period is ruled out, but we suggest a very plausible shorter period of 7^h.762, implying, at least at this opposition, one maximum and one minimum per cycle. A similar ambiguity is present for 804 Hispania also. The period could be either 14.^h.84 or 7^h.42. These two objects are typical of a class of asteroids whose periods are uncertain by a factor two. A short discussion on this problem is given. For 814 Tauris a long period of 35.8 hr is found, confirming the tendency of dark asteroids of intermediate size to rotate more slowly than larger ones. Finally a single-night lightcurve of the fast-moving object 1982DV is presented. Our observations agree very well with Harris' results (1982, private communication).