I've switched to <strong>SEP multistar</strong> for the guiding and using the default settings only, it seems to be working nicely. I'm sure I can do better once I start tweaking it...
HEQ5 pro polar aligned using the Ekos PA assistant
QHY5L-II-M via a ZWO OAG (I was expected better stars to be honest, but it will do)

I dropped the Exposure time to 0.5s for a test and wow the guiding looks better.

That does look good. One thing I have been wondering, but have not had the time to test, is how much focus matters to guiding. I use a ZWO OAG, like you, but do not have the focus dialed in as good as yours is. I wonder if that is hurting me at all.

By all mean I am not an OAG expert, but from what I understand:
the filter wheel/drawer must be after the OAG and not before (CCD + filter + OAG + telescope)
you need to get focus on your main camera first then you focus the OAG guide cam
if the main backfocus is 55mm then OAG to guide cam ccd must also be 55mm

Thank you for the hints, it is set up correctly to come to a good focus, I just do not have a good focus on on the tracking camera yet. It has been "good enough" focus, I guess you could say. Just wondering if that hurts tracking.

what is the weight load on your mount ? I am payload overloaded and can only get that rms response
from the new SEP guide algorithm under optimal sky conditions and certain targets regardless of camera
exposure time.

Without checking every thing, no more than 3KG or 3.5KG I would say.

Dean,
FWIW, I rarely get guiding working that well either (I use an Atlas Pro, which I believe is pretty similar to the HEQ5 pro, though not sure).
Some of it depends on the seeing and the sky position of your target.
I find, though, that using the GPG RA guide algorithm helps me.
Are you using that?
BTW, GPG RA guiding resets every time you slew, and it can take 15 minutes after a reset to get to its optimum performance.

Thats interesting! I will try that tonight.

+1 for sep multistar. For me even calibtation is quicker and succeds every time + better guiding

If this evening I get another nice one, I will be testing the guiding only, with difference exposure time.

Hy,

I have had good guiding, around 0.5", albeit under dark rural skies while on vacay, so its frustrating
not to get close to that. I use the GPG RA with major period set to 638 s (found on another post somwehere)
and tried without noticeable improvement by toggling estimate period. I will try a longer settle in to reach
optimum.

GTG,my SCT rig is much heavier but I hope to improve guiding after removing the guidescope and
replacing with a ZWO OAG that is coming in today. I would have thought with such a light load your guiding
would be much better. A WO GT71 is also coming today and I am keen to see how guiding that scope
on the HEQ5 works out.