[asimov (John)]

ok. If you were to get the image as seen in this pic, & you were to stick your finger over the end of the OTA you would see something similar to that black bar in the pic. Then you kinda run your finger around the circumfrence of the tube until it looks something like in the pic. You then run your eye along the OTA to find the closest primary screw corresponding with your finger. Now it's just a matter of finding out which way to turn that screw (trial & error) incriments of 1/16th