ABSTRACT
The WC9 star HD 164270 faded by nearly 1 mag in June 1980 and September 1909. The photoelectric observations of the 1980 event, however, show that this remarkable occurrence was accompanied by no discernible change in the colors of the star. Null results of other Harvard patrol plates limit the allowed periods of these events to 70.8 yr, 35.4 yr, or 17.7 yr, and we give times of predicted eclipse in the hopes that others may confirm or eliminate one of these possibilities. If these events are eclipses, then any companion must be large and cool. The considered limitations of the physical parameters of this alleged companion are discussed, and some alternate interpretations are considered.