2 Photoelectric observations and reduction

To increase the observational data contained in the literature, mainly in the "Asteroid Photometric Catalogue" (Lagerkivst et al. 1987a) and its Updates (Lagerkvist et al. 1989, 1992), a long-term and intense photoelectric observational campaign was undertaken in collaboration with M. Di Martino and G. De Sanctis of Torino Astronomical Observatory. Besides the purpose of building lightcurves of the asteroids with observational constraints (Di Martino et al. 1994), its aim is to observe asteroids with few or incomplete lightcurves, preferably at suitable ecliptic longitudes to obtain $(A-\lambda)$plots with well distributed points in longitude.
The photoelectric observations, still in progress, have been carried out, since March 1992, with the 91-cm Cassegrain telescope at M.G. Fracastoro station of Catania Astrophysical Observatory (since 28 October 1995 this has been the new name of Serra La Nave stellar station of Catania Astrophysical Observatory). In Table 1 of the "Amplitude-longitude $(A-\lambda)$ plot catalogue of asteroids" (Riccioli & Blanco 1995), the date of the observational runs and the name of the observed asteroids are reported.
During the 23 runs of observations already made, each lasting on average ten nights, we have used the same instrumentation (photomultiplier, diaphragm, filters, etc...) and observing strategy (Di Martino et al. 1994). The transformation to the standard system was made by means of groups of standard stars, taken from Blanco et al. (1968) and Landolt (1973), usually observed every night on their passage at the meridian. Further information on the reduction and plotting procedure are reported in Di Martino et al. (1994).