On Saturday, August 31, 2002, at 11:13 PM, Taichi Kato wrote: > I have superimposed the curves and used the maxima as a > synchronization > point. I was refocusing during the minima on the JD515 curve, > so I may have > missed the actual > minima. You need to use a program like AVE to play with phasing the data to derive a period fit that works for the entire data set. If the star has a published period, you should use that as a starting point. I'm not familiar with this star, but you are right that it may have two minima and maxima i.e. a primary minimum and a secondary minimum. AVE is a great place to start. It's at: http://vsnet.astrogea.org/soft/ave/aveint.htm Cheers, Michael Koppelman http://vsnet.lolife.com/astronomy/