Further proof, if it was needed, that the ancient people of the Boyne Valley were interested in the heavens. This sundial will never work now because it is hidden from the sun due to an overhanging concrete ledge which protects the kerbstones from rain.

Other stones at Knowth and the ancient Boyne sites show that the Stone Age people had a huge knowledge of the workings of the heavens. There is some evidence that they understood the lunar cycle, known as the Metonic Cycle, and were able to predict lunar eclipses. At nearby Newgrange, the passage admits sunlight on Winter Solstice into the central chamber during a very special astronomical moment. And at Dowth, there is a kerbstone which may feature representations of heliacal risings.