Tex, The short answer is no.
For dials that have a gnomon that points at the North star, the EOT correction is done by rotating the dial face around that shadow casting edge of the gnomon. For your horizonal dial, imagine a rod welded at the top edge of the gnomon. The ends of the rod are supported in such a ways as to let the rest of the dial, including the face to freely swing. EOT adjustments can then be made by rotating the entire around the axis of the rod about 4 degrees in either direction. For an equatorial or armillary this is easy to envision as the dial face rotates around the gnomon rod. This equally true for all reclining, declining, horizonal, and polar dials, but not as easy to envision. I know other's has gotten around this by arrainging all of the hour lines to be equal number of degrees apart. But then other parts of the dial, such as the type of gnomon used, must change. ++ron >> Here is my theory: Could you look at it and tell me what you >> think? What if (after properly calculating hour lines, and designing the >>gnomon properly for your lattude) that you could mount the gnomon so >>that it is properly oriented to the north but NOT ACTUALLY touching the >>dial plate. That is to say, it sits a tiny fraction of an inch above the >>dial
