Photoelectric observations and epochs of minimum light, SW Lac.

The W Ursae Majoris-type eclipsing binary system 5W Lac was observed photoelectrically on four nights in 1977. A total of 300 B and V observations was obtained. One secondary and three primary eclipse curves are well defined, and four epochs of minimum light and an updated ephemeris are presented. A listing of all available photoelectric times of minimum light, along with a brief discussion of the period behavior of the system, is also given. Although the entire light curve is not defined, variations in the shape of the light curve are evident.