Loosen the lock on the PCL-II panning clamp and swing the upper rig left and right noting the alignment of the targets. In this case the slide is too far back. The bad alignment is caused by parallax error (what we're trying to avoid). Let's try another slide position...

Loosen the lock on the PCL-II panning clamp and swing the upper rig left and right noting the alignment of the targets. In this case the slide is too far back. The bad alignment is caused by parallax error (what we're trying to avoid). Let's try another slide position...