On the day of the new quarter the shadow cast by the higher stone moves across the lower stone, which stands 19m away.
The animation shows the new quarter based on the Vernal Equinox defined as 1) “Heigth model equinox”, and 2) “Refraction equinox”. see definitions in Days-of-the-calendar.
The gradient of the top of the stones are in good alignment with the sun’s path.
The shadows movement across the stone is correct based on 14th March 645, 28 days after the vernal equinox defined as “refraction equinox”.
Despite the fact that the higher stone today is leaning, one can today see how the shadow falls. The next opportunity is 30 days after the vernal equinox on 19th April 2015, between 6:.55 and 7:00.