Astronomical Alignments at Knocknarea

When the Fianna were washed and dressed, the Red Woman brought them into a great hall, where there was the brightness of the sun and of the moon on every side. From that she brought them into another great room; and although Finn and his men had seen many grand things up to that time, they had never seen any sight so grand as what they saw in this place.

The Red Woman by Lady Agusta Gregory, 1904

The great cairn of Knocknarea is the focal point of the extensive network of ancient sites in Sligo. The huge passage-grave is visible from almost every ancient monument in the region, and some, such as Cairns E and K at Carrowkeel are directly oriented on it. The oldest Irish name for the mountain translates to Hill of the Moon, and in the myth of the Red Woman, where Fionn and the Fianna are invited inside the mountain, they enter a cavern with the brightness of the sun and moon.

Two stones, a large gneiss boulder with cup-marks, and a flat slab of limestone mark a line running from north to south through the cairn; another great boulder lies 0.5 kilometers north of the site. Several of the smaller megaliths - three ruined monuments and a hut site also lie on this cardinal line. This linear arrangement of monuments on Knocknarea has been compared by Stefan Bergh to the layout at Newgrange. The circular clustered arrangement found at Carrowmore is also echoed in the layout at Knowth in the Boyne Valley.

The Hill of the Moon

Athough the passage and chamber of Queen Maeve's cairn are hidden from view, several astronomical alignments can be guessed at for Queen Maeve's Cairn. My own belief is that there is an east and a west facing passage within the cairn, and that it is aligned to or near the equinoxes similar to Knowth in the Boyne Valley. There are certainly equinox alignments involving Knocknarea and Carns Hill eight kilometers to the east.

From the huge cairn on Knocknarea a vast panoramic vista opens before you. From this platform, at sunrise on the equinoxes, the sun comes up in the east, over Lough Gill, 'The Lake of Brightness' in Irish. At sunset on the equinoxes, an observer at the western cairn at Carns Hill, just south of Sligo Town, can watch the sun setting over Knocknarea.

The sun does not set directly behind the cairn on the equinoxes, but the ruined sites arranged in a north to south line would have created a series of bumps and notches which could be used for surveying the sunsets and moonsets. This certainly hints at the kind of ritual astronomy associated with these monuments.

Misdummer Sun Set at Shee Lugh and Sheemor

From Queen Maeve's Cairn, the winter solstice the sun rises in the Lough Arrow region over the legendary ridge of Moytura with it's Cairn, Shee Lugh. It is possible that the alignment is to the Hill of Sheemor, which lies beyond Shee Lugh and is visible from Knocknarea on a good clear day, peeping out from the edge of the Arigna Mountains.

Of course, the reverse holds true, and the summer solstice sun sets behind Knocknarea when viewed from Shee Lugh, as illustrated in the photo above. This is quite a spectacular landscape alignment - the sun dropping behind the cliffs at Strandhill on the left side of Knocknarea. The sun no longer drops behind the cairn - the obliquity of the ecliptic, the wobble as the Earth spins through space - has offset the alignment by 1.5 °, or three solar diameters.

Lunar Standstills

The lunar standstill is probably one of the most important Knocknarea alignments. The Moon's cycle takes 18.6 years to complete as it moves from it's most northerly to it's most southerly positions. At the southern summer rising position when viewed from Queen Maeve's Cairn, the Moon rises over Lough Arrow and crosses the Carrowkeel sites in the Bricklieve Mountains, to set behind the cairn topped hill of Knocknashee. This is the shortest time that the moon spends in the sky during its cycle. A similar alignment is known at the neolithic circle at Callinish on the Isle of Lewis.

At the other end of the cycle, near the winter solstice when the Moon drops into the sea in the region behind Croughan, it will illuminate the chambers of four of the Carrowkeel Cairns.

The View from Queen Maeve's Cairn

The huge cairn on Knocknarea is the most important piece of hardware remaining from the Irish neolithic in terms of its perfect horizon and observation platform. The cairn is pretty much in its original shape and form, minus its sheath of white quartz. The flat summit of the cairn has a tremendious view of the surrounding horizon and is a perfect location for making astronomical observations. It is not hard to believe that the ancient farmers, who had migrated by boat from Anatolia, were observing the basic clock of the Planet, the cycles of the sun and moon as they work their way across the horizon. Knocknarea has a wonderful horizon with huge views in all directions and many important sightlines marked by other sites and monuments.

Samhain Sunrise at Carrowmore

The central chamber at Listoghil, the focal monument at Carrowmore, four kilometers east of Knocknarea, is aligned to the sunrises in early November and early February. The massive limestone slab which covers the chamber was quarried in and transported from the Glen, close to the monument at Primrose Grange on the south side of Knocknarea.

Research on passage-tombs has shown that the builders liked to incorporate materials from locations, sometimes quite a considerable distance from the monument–the kerbstones, cobbles and quartz at Newgrange, Knowth and Dowth, for example, were transported from as far as sixty kilometers from the monuments. At Listoghil, the capstone may represent an ambition to include some of the substance of Knocknarea within the monument. The small sandstone supporting stones came from Scardan, a few kilometers to the north and the quartz (only fragments were found) came from the area around Croughan six kilometers to the south. The gneiss boulders are glacial erratics, transported to Carrowmore in the apron of the Cailleach Garavogue in local traditions. All these materials combined to create a chamber designed to capture the sun at specific times.