5. A Horizontal Review at Listoghil

In attempting to establish the palette of choices that confronted the megalith builders I undertook a horizon survey, checking for features of possible significance such as hills and depressions. To facilitate this I used a combination of onsite observation, a panorama of images taken from Listoghil, and data from see Table 2).

For comparison purposes, I entered the approximate positions of sunrise/moonrise at a series of positions that coincided with seasonal cusps or that have astronomical or phenomenological interest to modern skywatchers. The solar events noted were:

5.1 Points of interest

No attempt was made to establish stellar or planetary alignments, as only astronomical events at or near the horizon were being assessed. These would exclude stars partly because of atmospheric extinction rate, in which the rising and setting of stars are often hidden by the brightness of either the sun or the moon, and also because of the number of variables admitted in attempting to argue stellar alignments from Listoghil. In order for monuments to have been based on alignments with stars, stars at higher azimuths would have had to be considered; one then must make a decision as to the boundaries of elevation from the horizon. There are further complications, such as what time of night was significant. Over the course of any given night many stars roll into view. The apparent precession of the stars over time adds to the difficulty of assessing star alignments (The recording and analysis of data around possible Neolithic stellar alignments could constitute an area of further research).

The sloping roof of the chamber might be argued to point towards an elevation of 6.1°, but alternatively the tilt may be cited in support of a horizon alignment, as a device designed to facilitate the memorable effect of the 'capture' of the first rays of the rising sun. This illumination ceases once the sun's elevation is equal to or greater than the tilt of the roof-slab. At any rate, we are dealing here with a monument of considerable antiquity; the stones and building techniques are relatively crude, enhancing the attraction of bigger, more obvious targets.

The moon, at various phases, has risen in the general area of the saddle many times, in the course of hurrying backwards and forwards along the horizon monthly. Any position on its route is so frequently visited as to make a particular intention in this regard difficult, if not impossible, to decipher, given the absence of a precise temporal reference point for the construction of the chamber. A simple solution to this is to seek to isolate, again, the big targets; particular circumstances, 'celestial landmarks' which might be significant across the longue durée. One such might be moon phases or standout events such as lunar eclipses around the date of construction; but this topic is beyond the scope of the present article. Another solution would be to focus on what Ruggles calls 'directions of possible lunar significance'; there are eight of these; the northern major limit, the northern minor limit of both moonrise and moonset, and the southern major and minor limits of moonrise and moonset (Ruggles 1999, 36-7). (However for a useful précis of the difficulty of observing and recording lunar extremes for Neolithic observers see Sims (2006)). I superimposed these positions over my horizon map, and made comparison with my list of significant horizon features (see Table 2).

A list of 'points of interest' along the horizon was checked against 18 astronomical positions; 14 'significant horizon events' charted by Ruggles (1999, 37) plus a further four: the equinox and (solar) seasonal cusp markers. At present most of these have been done on the basis of measurement and prediction only, using the tools provided by the Geniet website (Figure 15). Further observation is needed to record phenomenological description and comparison.

Figure 15: Panorama of the horizon around Listoghil with seasonal sun positions marked [Static image]

5.2. Axes of seasonal cusps

The 360° survey from Listoghil revealed a number of new possibilities of coincidence between notable horizon features and some of the listed 'significant horizon events'.

In the course of the horizon survey I turned up 32 points that were visually striking, including hilltops, valleys, and hollows. When placed alongside the 18 areas of possible astronomical significance 8 'hits' were scored; three on minor lunar standstill events, the northern sunset limit, the southern sunset limit, and the southern sunrise limit. Apart from Knocknarea and the Ballygawleys, two other hilltop sites at opposite sides of the horizon coincided with 'astronomical directions', the northern limb of Truskmore Mountain (northern major moonrise limit) and the eastern limb of Doomore (close to the distant passage tomb on Knocknashee), cairned with a possible passage tomb (the minor lunar moonset limit).

Of the hit agreements between the lists, three occurred in the Ballygawley Mountains and three were in the direction of Knocknarea, a total of 75%. This bias may partly be explained by the prominence of these sites from this location and the percentage of the horizon they occupy, about 15% of the total. But it may also indicate a relationship to those positions. Interestingly, however, it is the edges or extremities of these targets that seem to attract attention, rather than the centres; for example there is no coincidence with the centre point of Knocknarea, the location of Queen Meadbh's Tomb, but two of our 18 targets fall on either limb of the mountain. Likewise, two others approximately define the northern and southern boundaries of the Ballygawley Mountains.

This harks back to Bergh's comment that the presence of Knocknarea may have influenced the location of the megalithic cemetery at Carrowmore (2002, 150). To this I would add that a second focus, the Ballygawley Mountain range, with its distinctive rounded forms, may also have been part of the narrative that influenced the story that informed the positioning and layout of the Carrowmore complex. It is often remarked that any axis of orientation implies twin directional possibilities. An imaginary line, drawn between the saddle to the east-southeast and the northern edge of Knocknarea to the west-northwest, connects the winter-start/end sunrise and the summer-start/end sunset (Figure 15). This line accords with the general direction of the peninsula; looking along it from the Ballygawley saddle it appears to represent the axis of the landform, with Knocknarea lying off-centre to the south. The axis crosses the Listoghil kerb twice, firstly at the southern edge of K43 (a stone distinctively marked with a curious, natural, 'footprint'), and after bisecting the chamber, it emerges on the opposite side of the kerb across some inconspicuous kerbstones. It then skims the edge of Carrowmore 52 and strikes the horizon on the northern cliff edge of Knocknarea Mountain. Both Listoghil and Carrowmore 26 are sited on this line (see Figure 2) and the axis passing through them (see Figure 18) appears to have informed their morphology and directionality (This led me to look in more detail at the re-working of Carrowmore 26 in the Bronze Age). Although there is a preference towards the east-southeast implied by the directionality of the Listoghil chamber, the suggestion of an axis of seasonal cusps drew my attention to the opposite horizon–to the west-northwest–as another potential point of interest.

5.2.1 Rolling down the hill

On the 1 August 2012, I observed sunset on the northern edge of Knocknarea. The sun appeared to roll down the hillside. The sinking sun dimmed at 21.13, as it passed behind the north escarpment of the mountain. Two minutes later daylight was briefly renewed as the disk emerged at the foot of the hill. At 21.23 the sun had disappeared fully below the horizon. A more distinct 'double sunset' may have occurred on the following evening, which unfortunately was cloudy. I have not yet observed the Bealtaine sunset at this position.

Sunset occurred at 298 azimuth, close on the Listoghil axis (about 182 degrees from the saddle). It appears to line up directly on 2 August and (predicted) on the 9 May (Reijs' calculator shows this occurring on the 4 August and 11 May in 3550 BC). Marked on the horizon by the axis of Listoghil, therefore, 'summer' and 'winter' are of different lengths; 86 and 102 days respectively, reflecting the eccentricity in the orbit of the earth around the sun. The combination of apparent altitude, the movement of the sun and horizon features on opposite horizons conspire to reinforce the 'axiality' of the Listoghil chamber.

The second event noted is equinoxal sunset. As mentioned in section 2.2.1, K1 lies in this general direction. During the biannual 52-day transit of sunrise across the looming mountain to the west, from Lunasa to autumn equinox, and from Bealtaine to spring equinox, Carrowmore is cloaked in the evening shadow of Knocknarea. In summary, from the vantage point of Listoghil, the start and end points of the transit of sunrise across the Ballygawley Mountains, and of sunset over Knocknarea, mark approximate seasonal cusps.

Besides these, no other horizon events from Listoghil appear to possess comparable myth-making potential. Besides the two lunar events at distant hills already mentioned, the other two lunar events occur on the extremity of the shoulder of Knocknarea and over Aughamore Far. The other lunar minima and maxima occur on inconsequential parts of the horizon, as does the Samhain/Imbolc sunset. The second possible seasonal axis, from the Bealtaine/Lunasa/(summer-start/end) sunrise to Samhain/Imbolc (winter-start/end) sunset is not marked by notable natural or man-made structures at Carrowmore.

Because of the 'privileged' latitude of Listoghil the solstices appear to line up on axes (Ruggles and Barclay 2000, 72). Midwinter and midsummer sunset and sunrise face each other along these lines. Midwinter sunset and the summer solstice positions do not coincide with notable horizon markers. The directionality of Listoghil suggests that the beginning and end of winter was the builders' focus. The interaction with Cailleach a Bhérra may suggest midwinter as an additional point of interest.

Figure 16  Figure 17

Figure 16: Close-up view of saddle from the west. The embankment marking the barony boundary can be seen to the left.
Figure 17: Elevation profiles, Cúil Irra Peninsula (after Google Earth). Elevation exaggerated by a factor of three. Top: profile W-E. The Atlantic ocean to the west, Lough Gill to the east. Centre: profile N-S. The Carrowmore complex occupies the most elevated position here, straddling twin ridges running E-W. Bottom: profile along ESE-WNW axis

5.3 The saddle

The 'saddle' (Figure 16) towards which Listoghil points is a natural feature, located in the Ballygawley Mountains, 6.15km from Listoghil [171702/330716]. It stands approximately 193m above sea level. The left-hand side of the saddle is actually a rocky ridge, viewed along its length; thus foreshortened it appears as a mound, or spur, from Listoghil. The right side is a conical mound of gneiss rock, with boggy vegetation growing on it. The gently curving valley in between the spurs is formed by great outcropping slabs of metamorphic rock, similar to the gneiss in the Carrowmore monuments. The rock outcrops contrast in colour and texture with the blanket bog and its vegetation cover; the bog fills any depressions or hollows. Strewn all over the landscape are loose rocks and boulders of different sizes. There is an abundance of small pieces of whitish quartz, very like the pieces of quartz that accompany the dead in the Carrowmore satellite tombs. This material is visible also, as seams running through some of the metamorphic slabs.

The general area is, to modern eyes, one of exceptional natural beauty. The saddle enjoys overviews of Lough Gill, the Garavogue River and the Cúil Irra peninsula with the sea flanking it on either side. But the view north-west is dominated by the singular shape of Knocknarea. 'Behind' the saddle to the east lies Lough Lomman, a high corrie lake.

An observer at Listoghil, looking towards the Ballygawley Mountains is looking along the boundary of the Tuatha. A linear earthwork [SLO21-110----] runs spine-like for 1.6km across the Ballygawley Mountains along the boundary between the baronies of Carbury and Tirerrill (Egan et al. 2005). It crosses four townlands, including the area of the saddle. The four Ballygawley passage tombs lie on or close to it (Bergh 1995, 86). The node marking the south-most point of the Barony of Carbury is positioned at the centre of the passage tomb at Cailleach a Bhérra's House [SLO20-129], in Carrownamaddoo Td. Cailleach a Bhérra's House has a four-metre passage leading to a simple rectangular chamber. The chamber points to the SSW, to a position never attended by solar or lunar horizon events.

5.4 Alternative targets

Non-astronomical explanations for the direction of the Listoghil chamber must be considered e.g. ancestral topography. Below I have listed a number of possibilities; some of these are well-rehearsed. But we have to allow that outside our field of vision in this regard are various unknown possibilities.

The possibility has to be entertained that priorities varied regionally, that at some sites orientation was much more significant than at others; that despite axial plans, despite the occasional regional occurrence of some remarkable horizontal conjunctions, that sometimes your monument pointed to somewhere completely arbitrary or to something so specific as to be undecipherable. Alternatively there are examples of flock orientations, where clusters appear to scatter in a broad general direction like buckshot or according to general rules such as circularity, which are inimical to individual consideration but may be of statistical interest. At both Carrowkeel and Carrowmore the majority of sites appear not to possess astronomical orientation.


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