Similar analyses were carried out on all the sources monitored during the observing run at the Wise observatory in January 1995. Stars were analyzed without knowledge of color or location so that human biases could be minimized. Usually, the PDM and periodogram codes returned several candidate periods. In many of these cases, more than one period satisfied the criteria given in Chapter 3. In these situations,
the folded data were fit to a high--order polynomial function. The use of the polynomial fit adds a smoothness criteria to the method used by the PDM code, which simply tries to connect the data points using the shortest possible ``string''. The standard deviation of the data to the fit was then measured. If more than one period was found, the one with the lowest standard deviation was chosen. To keep computation times reasonable, the periodogram code has a limited number of bins, thus it has limited temporal resolution. Because of this, standard deviation minimization was also used to fine tune the period.