Phd dec guiding

[pjphilli (Peter)]

Hi

The PHD graphs allow the DEC Guiding to be Off, Auto, North, South.
The Off function permits adjustment of polar alignment to be about zero or a drift towards the North or South directions.
My question is: Some say to set the polar alignment to about zero and use the Auto function for DEC guiding. Others prefer a slight drift in either North or South directions and then set PHD to guide South or North only respectively (thus avoiding crossing the backlash).
I would be interested in comments from those who have ACTUALLY USED
either or both of the above DEC guiding methods (or others for that matter) and their relative merits.

Cheers Peter

[multiweb (Marc)]

Hi Peter, I've alway used auto. I you balance your mount slightly east heavy you shouldn't have any problem with PHD sending pulses to reverse the DEC motor motion. If you know your drift is consistent in one direction then you can also use north or south if you wish. I used south once because of a balance problem in DEC and it worked for that one time as auto was oscillating.

[pjphilli (Peter)]

Thanks Marc - I think that you have hit on my basic problem which is that I have noticed on occasion the DEC guiding does a large jump which PHD takes about 6 DEC pulses to correct. In view of what you have said this could be a DEC balancing problem. Cheers Peter

[multiweb (Marc)]

Originally Posted by pjphilli

Thanks Marc - I think that you have hit on my basic problem which is that I have noticed on occasion the DEC guiding does a large jump which PHD takes about 6 DEC pulses to correct. In view of what you have said this could be a DEC balancing problem. Cheers Peter

Ha...ok. I have had that one too once. In my case too much backlash in DEC and when PHD reversed the motor in auto mode as you say it took 4 to 5 pulses to clear the backlash and guide again. By then I was getting image trail already at my image scale. Try to minimise backlash as much as you can In DEC. Sometime, most of the time actually, it is a compromise between tight and lose spots on the gear. If you still can't, then guide south or north depending on your drift as an alternative.