Published online by Cambridge University Press: 12 April 2016
We report the first results of an observational campaign consisting of coordinated photoelectric photometry of Ex Hya from four observatories at different geographical longitudes for a total of 146 hours in April 1979.
Ex Hya was monitored differentially for a total of 109 hours, partly simultaneously at different telescopes. The largest time-interval of uninterrupted observation is of nearly 18 hours. 68 times of eclipse, and 89 times of maxima in the 67-minute cycle have been obtained. Figure 1 is an 0-C diagram representing all residuals listed by Vogt et al. (1980), and those as obtained during this run.