Hi All,
Thought I'd share some observations.
PHD2 documentation says you should have a longer exposure time to overcome bad seeing. My observations do bear this out.
I have been recording my PHD2 findings for the last four months (using PHD2 Log Viewer). If I graph a scatter plot of Exposure Time (ms) and Total Error (RMS Arc Minutes) I get:
As you can see going up to 3 to 3.5 seconds does make a difference!
Hopefully this will help someone who is starting out with guiding.
BTW: I have a 200mm F5 scope and I use an off axis guider.