STi profile for PHD2

I am trying to setup my SBIG STi autoguider connected to an OAG on ST8300M that is connected to an AT8RC scope.

For the life of me, the new guider profile I create for PHD2, shows an all white image.

Here are my profile parameters:

The AT8RC has a FL of 1625mm
The SBIG OAG attached to SBIG ST8300M has a 0.7 times FL multiplier
So for the autoguider profile I use:
FL = 0.7*1625 = 1137.5, rounded to 1137
Pixel size = 7.4 microns

Is there something I am doing wrong?

Shailesh Trivedi

Hi Shailesh, there’s some information about that in the troubleshooting section of the PHD2 Help: Manual - PHD2 Guiding
Feel free to post any PHD2-related questions in the PHD2 Forum Getting Help - PHD2 Guiding

Thanks Andy. Now I am able to see a single star (not a hot pixel, and this is quite a starless field). But the handshake with SGPro is a bit problematic. The settings show SGPro to wait 10 seconds to get to < 0.5 pixel distance and this does not seem to happen and SGPro times out after a long wait. Since I have got the same setting to work previously except for this 1137 FL on the OAG, I am wondering if I need to make any changes to the guiding rate which defaults to 0.5X siderial.


Does anyone have any experience in OAG based autoguider focusing for long FLs. For example I have a SBIG 8300 OAG with STI autoguider. The OAG is attached to SBIG ST8300M on a AT8RC which has a FL of 1625. For the life of me, after an hour of careful focusing and refocusing, I am unable to get stars in focus with PHD2.

SGPRO (and maybe this is a setting thing) CP I have set to < 0.8 pixel for settling time and it cannot hold to 0.8 pixels for 5 seconds and I end up waiting endlessly.

I had no issues with the same STI camera on its own 300mm scope, but of course with the OAG the FL is 1137 after applying 0.7X reduction that comes from the OAG optics.

Any suggestions will help.