SteveD What exactly is the difference between Dec Mode
North and South modes only issue correction pulses in one direction, Auto sends correction pulses to both north and south directions.
If your polar alignment biases the mount to drift in one declination direction, or if your declination axis is unbalanced, a North or South dec mode can reduce the autoguided error (keep in mind that your dither will also be limited in one declination direction; but that is not usually a problem).
Set the Declination correction mode to Auto in general, but if the vast majority of your declination correction pulses are in one direction, using something other than Auto could reduce your autoguided error, especially with mounts with poor backlash.
Overall, if you do have a declination bias, it is best to correct the declination balance and/or polar alignment, instead of relying on the North and South declination correction modes. Use them as a last resort, not first resort.
Chen
