[Shiraz (Ray)]

Hi Tim.
FWIW, my EQ8 has never done anything remotely like as good. However, if this is a guide graph with an incorrect pixel scale and timebase, it might indicate that your EQ8 is guiding normally.

suggest that you look at the following maybe:
- the worm period in your data is that of an EQ6, you need to set up an EQ8 in the startup panel, so that you get the right worm period - your FFT shows a PE residual at about the 198 sec worm period of the EQ8, so that bit is working right
- the pixel scale is possibly way out, did you set the guide scope focal length and guide cam pixel size in the startup panel and is dec correction on?
- as others have said, PE measurement requires that the guiding be turned off in phd2 while you do the measurement - this looks like you had guiding on.

In general EQ8's seem to come in at around 7 arcsec p-p PE and guide to better than 1 arcsec RMS. The worm period is short though, so you need fairly short guide exposures to ensure that PE does not leak into guiding - I find that 0.5-2 seconds works OK with mine and I don't need any PE correction (which is just as well, since it doesn't work in EQMOD). your data might indicate the level of guiding accuracy if you can correct the pixel scale.