[Omaroo (Chris Malikoff)]

Originally Posted by multiweb

I think PHD doesn't care about the orientation of the camera. I remember Craig Stark saying that in one of his posts a while ago. That's the best thing about it. It doesn't care where North, south East or West is in the camera FOV. I'm pretty sure though that calibration is to know how far the mount moves for a known pulse time. pemPRO calibration works exactly the same way. The program needs to know how far the mount is going to move so then it can scale the pulses for known deviations while guiding. That's my understanding of it anyway.

I read that too, and from it read that the PHD user doesn't have to care, as such (which is the best thing about PHD) - but PHD certainly does. How else is the software going to issue an instruction to the mount to move in +/-RA or +/-Dec in reaction to star centroid movement if it doesn't know exactly where the axes are on camera?

From Stark Labs site:

In PHD Guiding, all calibration is taken care of automatically. You do not need to tell it anything about the orientation of your camera, nor do you need to tell it anything about the image scale. The automatic calibration routine takes care of this for you. Odds are you won't ever need to set a single parameter. Just select your star and hit "PHD Guide" and let the software take care of it.