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1. Introduction

We made the observations in order to improve spin periods and to measure lightcurve properties of some previously less well observed asteroids. This work is a continuing process and has been previously reviewed by Binzel et al. (1989) and Lagerkvist & Claesson (1996). The frequently updated version of a spin period table is available by anonymous ftp from in the directory pub/Asteroids/RotationPeriods. The spin periods in this paper were determined with a method described by Magnusson et al. (1993). Accurate spin periods are needed in order to improve e.g. modelling of asteroid shapes. For some asteroids included in this paper, future observations from one more apparition may lead to a possibility to determine the spin vector. We also give improved periods for some asteroids and confirm some other periods.

We also measured UBVRI-colours for most of the asteroids. This work is complementary to the spectroscopy, e.g. by Gaffey & McCord (1979), and narrow-band photometry, e.g. by Chapman & Gaffey (1979). We encourage future asteroid observers to include also UBVRI-observations if the filters are available.

Copyright by the European Southern Observatory (ESO)