CCD photometry of 23 minor planets

We present CCD photometric observations of 23 main-belt asteroids, of which 8 have never been observed before; thus, the data of these objects are the first in the literature. The majority showed well-detectable light variations, exceeding 0 m . h 1. We have determined synodic periods for 756 Lilliana (9 . h 36), 1270 Datura (3 . h 4), 1400 Tirela (13 . h 36), 1503 Kuopio (9 . h 98), 3682 Welther (3 . h 59), 7505 Furushu (4 . h 14) and 11436 1969 QR (12 . h 3), while uncertain period estimates were possible for 469 Argentina (12 . h 3), 546 Herodias (10 . h 4) and 1026 Ingrid (5 . h 3). The shape of the lightcurves of 3682 Welther changed on a short time-scale and showed dimmings that might be attributed to eclipses in a binary system. For the remaining objects, only lower limits of the periods and amplitudes were concluded.