Attempting to explain the Drift Method of Polar Alignment
This is the preferred method for aligning the telescope mount to follow the motion of the night sky. Actually, to counter-act the motion of the Earth. In a letter to Dr. Russell Cockman, we were discussing the method. I decided I had a very easy and clean description of the process. So here is the method described in my letter to the good Dr.Cockman.
"I have learned the drift method finally. I was a bit confused by the unclear descriptions of how to adjust for drift. It is so simple if you think of it as a declination drift ONLY alignment. Point the telescope at the meridian and +20° dec then watch for north/south drift in DECLINATION. If it drifts right, move the star left, and vice versa. When you have no drift after 5 minutes, then go to the eastern horizon and find a star at about the same height off the horizon as the pole star. Do the same thing again. Look for DECLINATION drift and correct until steady. Go back and forth a couple of times until it is not necessary to adjust anymore. If your right ascension axis is poor, well there is no help for that except to revamp the drive or go for a periodic error correction system."
-David Ryle 2002
In regards to the above description, all I can say is I need to try again. There is no mention of HOW to adjust for drift! DUH! Here is a better shot at it;
Start by getting Polaris (or the southern celestial pole) in line with your RA axis, and the mount leveled. Use at least 150x power and a crosshair illuminated guiding reticle will help. Point the telescope at a star at the meridian and close to zenith, preferably close to 20° declination. Lock down and run your RA drive. Look for declination drift. If the star drifts, then adjust the AZIMUTH axis to make the star return to the center. Keep at this until you have very little noticeable drift.
Now aim the telescope at a star at the eastern horizon, about the same height up as Polaris is for your latitude.(or the Celestial South Pole for southern observers) Watch again for declination drift. If the star drifts, then adjust the ALTITUDE axis to bring the star back into the center again.
Repeat the steps several times. Each time will bring the declination axis closer to true alignment. All you really have to remember is the drift at zenith is adjusted by the AZIMUTH axis, and the eastern drift is adjusted by the ALTITUDE axis.
If there are any more tips or lost points that need clarifying, please email me at davidr@wf.net.
Other polar drift alignment methods are described at these links;
http://www.aa6g.org/Astronomy/Articles/drift_align.html
http://www.syz.com/rasc/polralgn.htm