The Sun and Moon Dagger Trilithon

The Sun & Moon Dagger Trilithon forms an image of the sun (or moon) on the ground, and three daggers of light. Two graze the upright stones mid-morning and mid-afternoon and the third reaches out to touch the sun or moon image at transit (local noon for the sun). The angle of the grazing daggers changes with the seasons: the solstices and equinox positions are indicated by smoothed triangular areas on the north faces of the uprights. These events are observable every clear day and nights near full moon.

Summer solstice morning dagger
Summer solstice mid-day dagger

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