GSC 748-1618 period

[Michael Koppelman <lolife@bitstream.net>]

So I'm working on GSC 748-1618. I have TASS data and I have my own 
data. When I use only my more recent data it looks like this:

http://www.lolife.com/astronomy/gsc748-1618/7481618_phase_1.jpg

While perhaps not the actual period, it is clearly related to the 
period.

When I add all the data, which includes the TASS data and my earliest 
data, the same period looks like this:

http://www.lolife.com/astronomy/gsc748-1618/7481618_phase_2.jpg

It seems like maybe I'm just off by a factor of two or something, but 
I've tried every probably period between 0.5d and 3d and I can't find 
anything that makes all the data work.

The data is here:

http://www.lolife.com/astronomy/gsc748-1618/data_hjd.txt

If you are interested.

Thanks for any insights. It is possible the period is changing on the 
time scale of a year or so?

Michael Koppelman