Banner: Knocknarea at Sunset.
An early engraving of the passage and chamber of Newgrange by Charles Vallancey.

The Roofbox and the Winter Solstice

The best known feature of Newgrange today is the orientation of the passage and chamber to the winter solstice sunrise, using a special feature nowadays called a Roofbox. The alignment was noted by the astronomer Locklear in 1909, and the symbolism of the rising sun was used as an image in the poetry of the mystical writer A. E. or George Russell.

The phenomenon was first recorded in modern times by excavator Michael O' Kelly in 1967. The O'Kelly's had heard many reports of the sun lighting up the chamber at midsummer, but upon investigation was found to be midwinter sun rise.

Newgrange around 1901.
Newgrange around 1901.

The entrance faces south-east and as the sun rises over the days around December 21st, its rays enter the specially contrived roof-box structure over the door and penetrate 20 meters into the mound to illuminate the chamber. The only other roof box currently known is at Cairn G, Carrowkeel in Co. Sligo, which was probably built two or three hundred years before Newgrange.

Sun receding down the passage of Newgrange, December 23 1998.
Sun receding down the passage of Newgrange, December 23 1998. Photo taken on a cold morning near solstice after waiting outside while almost 35 people huddled within the chamber. The sun refused to come out until the chamber emptied, and then seven of us got to go in and witness the beam of light receding down the passageway. It was well worth the wait in the cold!

The Newgrange roof box is a sophisticated structure which took a great deal of planning and engineering. Since the passage slopes gently up hill, the floor of the chamber is at the same level as the roof box. It allows the sun to enter for a maximum of 22 days over the winter solstice, or about 11 days on either side of the solstice proper.

A reconstructed drawing of Newgrange as it might have looked, based on the shape of Queen Maeve's cairn.

On solstice mornings given a clear sky, as the sun clears the horizon, it's rays flood into the roofbox and flash up the passage, penetrating almost to the end of the cruciform chamber. The beam of light is quite narrow, and stays in the chamber for approximately 17 minutes, before moving out and down the passage again. The light is so strong and bright that it illuminates the whole chamber, and the capstone, 6 meters above the floor can be seen. The engraved art is thrown into high relief.

During the excavation a quartz block was found in the roofbox; this was one of two used to close the skylight in ancient times when complete darkness was required in the chamber. It must have been well used, since it's opening and closing had worn a groove on the slab it sat on.

From Joseph Raftery's Prehistoric Ireland, 1949.

A large flat slab was used to seal the entrance to the mound; this was found lying flat behind the Entrance Stone, worn smooth by many years of people stepping on it as they entered the cairn. Today the door slab stands bolted in place to the right of the entrance.

For years people had to book a place to enter the chamber and witness the winter solstice sunbeam; in more recent years visitors get to fill out a card for a lottery when they purchase a ticket in the visitor centre. However, the sun can shine into the chamber for a number of days on either side of the shortest day, so there is no harm turning up near the solstice.

An old photo of the Roofbox lintel from before the mound was excavated.
An old photo of the Roofbox lintel from before the mound was excavated. Chunks of quartz and granite cobbles are piled up on top. In ancient times, two quartz slabs were used to close the roofbox aperture when it was not in use.

The display that takes place outside the entrance to the mound is quite spectacular. The quartz wall lights up with a bright yellow golden colour, which could surely be seen from many miles away. Martin Brennan was the first to note that the standing stones near the entrance cast shadows on the kerbstones.

The roofbox at Newgrange, a specially contrived aperture over the entrance which allows the rays of the rising midwinter sun to enter the passage and reach the chamber of this great neolithic mound.