Sundials remind me of calculus. Simple in nature and yet somehow quietly complex. This image conjures those feelings again and yet it is without question mechanical and low tech at the same time. The angle of the shot and framing in the cropped negative space is well executed. Just the right DOF and gold on black choice only adds to the whole. A few spots that seem over lighted and the center 'thing' above the glass seems far too shadowy. Overall a great interpretation of the challenge from the viewer's seat and solid marks for composition with only a minor hit on some technical distraction.
Great pic and subject, I can't help feeling that there may be a more dynamic angle/crop possible. Also I think that you would have better image if you had used a polarising filter to avoid the reflections on the glass.