This paper is based on observations obtained with the Carlsberg Automatic Meridian Circle (CAMC), situated at Observatorio del Roque de los Muchachos, La Palma, Spain, and operated jointly by the Copenhagen University Observatory, the Royal Greenwich Observatory, and Real Instituto y Observatorio de la Armada en San Fernando. The original observations were published in tabular form in the Carlsberg Meridian Catalogue, No. 6-8.
The instrument is, of course, primarily intended for astrometry, but photometric results of variable quality are obtained as a by-product. After removal of data obtained during non-photometric conditions, the remaining data have a typical accuracy of 0.05 magnitudes for 12th magnitude point sources. This modest accuracy is due to short integration times and a small aperture. However, this is compensated for by a very good solar phase angle coverage and homogeneity from apparition to apparition.
Since the instrument is constrained to the meridian, observations of a given object repeat essentially every night at the same sidereal hour. For asteroids with significant rotational light variation and a synodic spin period nearly commensurate with a day, problems may arise.
The majority of the 74 minor planets in Carlsberg Meridian Catalogues Nos. 6-8 were selected for observation for the purpose of improving their orbits in association with the Hipparcos mission. These were scheduled every second night. Some of the minor planets analysed in this paper were observed with the primary purpose of obtaining photometry for physical studies, and these were scheduled every night from western quadrature, through opposition, to eastern quadrature.