The glorious moment of sunrise over the sea is a captivating event. But this fantastic natural phenomena takes on a different meaning at the time of Winter Solstice, especially at ancient sites where this Solstice was marked in a special way by the Stone Age people.

At Baltray, on the east coast of Ireland and near the mouth of the famous Boyne River, there are two standing stones, one of which marks the solstice in a very unique way, linking up with the landscape in a union of heaven and earth which occurs just once every year.

The large stone points to Rockabill, two small islands out in the Irish Sea off the coast of Skerries, and located 15 miles from Baltray. In modern times the larger of the two islands has a lighthouse which is used to warn ships of the islands in the busy shipping channel which serves the port of Drogheda through the River Boyne, and also Dublin through the Liffey.

It is at Rockabill, on the shortest day of the year, that the sunrise occurs, rising in its most southerly azimuth for the whole year while 'standing still' for five days. Because of an effect of wobble on the Earth's axis, the rising position of the sun has changed slowly over time, and now the sunrise occurs two sunwidths (approximately one degree) to the left of Rockabill.

Archaeologists say that standing stones were erected from circa 2000BC onwards, with a more specific Later Bronze Age dating (c. 1400 - 700BC) for stone alignments (two or more standing stones), but the dating of stone alignments has been much debated. (Archaeological Survey of Co. Louth, Victor M. Buckley and P. David Sweetman.)

The Baltray stones are unique in Co. Louth, the location of many of the events and happenings in the epic Irish legend The Táin. because Baltray is the only existing alignment in the county. Two other stone alignments, bothat Carrickedmond, no longer exist. There are a total of forty single, or isolated, standing stones in Co. Louth.

Due to the often inclement Irish weather, the Winter Solstice sunrise and sunset can sometimes be difficult to see. In December 2000, around the time of the shortest day, the weather had been quite bad. We journeyed to Baltray on Tuesday, December 19th, but the whole sky was overcast and we didn't see a sunrise. On Dec. 20th, it was raining heavily so that was another no show.

There was better news on the day of the solstice itself (Dec. 21st). At 7:30am the thin waning crescent moon could be seen high in the sky, and by 8am it was obvious that most of the sky was free from cloud. However, there was some cloud lurking on the eastern horizon and this caused some problems, obscuring the sun for the first five minutes or so after sunrise, which occurs at 8:35am.

At Newgrange, where the sun normally penetrates the passage at 9:04am, there was a no show, much to the disappointment of all those who turned up. But at Baltray, the sunrise was glorious, and the cloud which threatned to ruin the whole event actually made the sunrise more colourful.

Regrettably, the presence of a misty haze at sea prevented us from seeing the Rockabill islands during the sunrise, but the photograph below shows the Winter Solstice sunrise of 1999 captured by Michael Byrne on video, with the position of Rockabill arrowed.

A number of visitors to Baltray enjoyed the sunrise event, and there were visitors on other days too despite the bad weather.

Given the obvious astronomical importance of Baltray, and its unique geographical location, we have concluded since making the discovery in 1999 that the site was very important. Ancient mythology indicates an astronomical significance, and alignments with another site have proven intriguing. The stones also mark moonrise around the time of Summer Solstice.

It is also important to remember that the standing stones are the first ancient monument encountered on the Boyne River, at the entrance to the Valley of the Kings. The stones would also have formed a marker for the border between the ancient provinces of Ulster and Leinster.