Abstract
The binary central star of the bipolar planetary nebula NGC 2346 is being progressively occulted by a dust cloud, presumably a by-product of the process that led to the formation of the planetary nebula. The authors present new photoelectric and photographic measurements of the stellar brightness; they show evidence of irregularities in the time evolution of the light curve, ascribable to inhomogeneities at the edge of the cloud; they use the cloud to improve the knowledge of some orbital parameters and characteristics of the binary system; they obtain a very high lower limit for the total density of material at the edge of the cloud; and they advance a speculation about the origin of this extremely dense object.
