THE NURAGHIC WELL OF SANTA CRISTINA, PAULILATINO, ORISTANO, SARDINIA. A VERIFICATION OF THE ASTRONOMICAL HYPOTHESIS: WORK IN PROCESS, PRELIMINARY RESULTS 10 BALTICA ARNOLD LEBEUF “O that the ladder to heaven were longer And the lofty mountain loftier! ARCHAEOLOGIA Then I would fetch and offer to my lord The waters of life Which Tsukuyomi treasures, And restore him to youth and life” Manyoshu (Shinkokai 1965, p.306). [Tsukuyomi is a Moon goddess]. Abstract The Nuraghic well of Santa Cristina, Sardinia has been regarded as a ritual monument built to receive moonlight on its water mirror at the time of the meridian passage of the moon when it reaches its highest point in the sky during and around the major northern lunistice. In this paper we investigate the precision that could have been achieved and conclude that the well could indeed have served as an instrument for measuring the lunar declination during half of the draconic cycle of 18.61 years. Key words: Moon, Lunar standstill, sacred well, Nuraghic culture, camera obscura, eclipses, Phoenicians. Introduction broken. Of nearly a hundred Nuraghic wells known in the island, almost all are built of rough stones: only The sacred well of Santa Cristina is situated in the neigh- three are of carved stones, and only Santa Cristina is bourhood of the small city of Paulilatino, in the Oris- preserved in its integrity. tano province of Sardinia. Its coordinates are: 40º3’41” V The general shape of the well is that of a long bottle. North, 8º43’58” East. This construction, built of per- Each horizontal layer is circular, with the upper open- V. REFLECTIONS fectly hewn stones of greyish-black basalt, has been OF ASTRO- ing measuring 27 cm and the diameter of the lower part dated by the archaeologists to about the year 1000 BC NOMICAL AND at water level being 255.5 cm. The upper opening is COSMOLOGICAL (Lilliu 1998, p.529; 2006, p.72; Santoni 1990, p.169- KNOWLEDGE IN 643 cm above the water level. MONUMENTS, 193). It belongs to the so-called Nuraghic culture of LANDSCAPES the late Bronze Age. The Santa Cristina well impresses The staircase leading down to the water is a monumen- AND ARCHITECTURE the visitor first of all because of the perfection of its tal construction trapezoidal in shape. The upper step masonry and the extreme elegance of its architectural measures 347 cm while the lower one is only 140 cm. proportions. It is unquestionably a masterpiece, com- The side walls of the staircase are built of horizontal bining unusual restraint in its general appearance with layers of stones as is the tholos of the well itself. The an incredible architectural complexity. At Santa Cris- overhangs of the layers of stone catch the sunlight dur- tina, the horizontal layers of stones are painstakingly ing the day and the moonlight at night, producing vari- worked and aligned. They are set in place without ce- ous extremely beautiful optical effects. ment, stone on stone, almost without any interstices. In contrast to other buildings of the same type, each The Astronomical Function successive layer is set slightly back from the one be- neath it, leaving at each level a space, a narrow margin In 1972, Carlo Maxia and Lello Fadda, building upon a of about two centimetres. This layout must be func- proposal of Eduardo Proverbio, presented an hypothe- tional, since it not only complicates dramatically the sis concerning the astronomical function of this unique geometry of each stone to be hewn or carved and the construction. According to these authors, the meridian general process of construction but also weakens these diagonal from the upper southern edge to the northern upper edges, exposing them to the further risk of being lower edge of the well is inclined at an angle of 11.5 155 - degrees to the zenith. Subtracting 11.5 degrees from The Archaeology and Documentation the latitude (40º 3’ 41” North), we obtain roughly 28.5 degrees. This value is very important because it repre- Of all the published plans, none was acceptable for ar- sents approximately the lunar declination at the time chaeoastronomical studies. The best ones were those of the major northern lunistice. It is regrettable, then, drawn by Prof. Enrico Atzeni who was in charge of the that although this idea was published several times in archaeological investigation and the restoration of the successive papers and repeated by different authors, it well in 1967-1973 and 1977-1983. The restoration is has not been better developed and more precisely de- perfect but unfortunately the archaeological investiga- The Nuraghic Cristina, Paulilatino, Well of Oristano,Santa Astro The Of Verification Sardinia.A in Work nomical Hypothesis: Process, Preliminary Results scribed. The different articles by Maxia and Proverbio tion was stopped before completion and leaves many only present approximate measurements and the plan, questions unanswered. Considering that the work was copied many times, lacks any sort of precision. I have not finished on such an important site, Professor Atzeni known of these hypotheses since their publication, but did not judge it suitable to publish his results, which it was only on the occasion of the 2005 SEAC con- he considers incomplete. So I had to draw the plans ARNOLD LEBEUF ference in Sardinia that I had the opportunity to visit anew. the monument. The first thing that struck me was the unparalleled perfection and regularity of the circles Description of the Phenomenon formed by the edges left between the layers of stones. of the Moonlight Descending I reasoned, then, that if the approximate measurements the Well of S.Cristina made by Proverbio could be confirmed, and that indeed every 18.5 years the moonlight reached the water mir- Owing to the proper motion of the Earth from West to 1 ror at the time of the major northern lunistice , then the East on its axis, the Moon, like all other celestial bod- other levels could have indicated the successive lunis- ies, moves through the sky from East to West. When it titial moon declinations during the rest of the draconic is high enough in the sky, its light entering through the cycle or part of it. If this were true, then this building upper opening reaches the first edge, between the first would have been much more sophisticated that had and second layers of stones inside the well (Bb in my hitherto been proposed, and we would have to consider 2007 plan). We must wait for some time until the moon it not to be only a symbolic and ritualistic construction gains enough altitude for its light to reach the second but also a scientific instrument capable of measuring edge, separating the second and third layers. The time the declination of the moon at the lunistice over a much taken to reach each successive level decreases steadily larger part of its cycle, and with much higher preci- from one step to the next as the moon gains altitude. sion. One detail of the construction had also attracted When the moonlight reaches the bottleneck (F-J of the my attention: although all of the layers of stones are plan), its rays are tangential to the wall of the well and approximately of the same height, about 30 cm, one so the light progresses more rapidly from one row to of them is conspicuously larger, about 45 cm, and this the next. If we look from the inside of the well, that is was surely significant. to say from the lower steps just over the water mirror, I returned to Santa Cristina in 2005, 2006, and 2007, it is impossible to determine the exact number of lay- first of all to observe the phenomenon of the lunar il- ers illuminated from the top because the line of sight lumination of the edges between the layers of stone in is tangential to the inner wall of the well and all the the well and to verify the supposed optical effects, but upper marks are confounded. Nor is it possible to count also of course to take a series a measurements with the the number of steps still untouched by the light, start- utmost care. We need two series of complementary ing from the water level, because we are in total dark- measurements: first those of the architecture itself by ness. In fact, comfortable and precise observation only classical triangulation, and then time measurements becomes possible from the moment the light reaches of the moments when each successive edge of a stone the lower edge of the single larger layer of stones (Kk layer becomes illuminated by the moon, i.e. the mo- - Ll) which is easily visible from the lowest steps of ments of first contact. We can then calculate the corre- the monumental entrance. We will designate the low- sponding altitude and declination of the moon for each er edge of this larger layer (Ll) to be level zero. The point of contact, which gives us a means of checking descending light creates a ladder. Because we are in the plan and, eventually, of seeing if it could have been a camera obscura, in the dark, the only way to count improved. the number of steps illuminated is to rely on the larger space defined by the two lines of light marking the upper and lower edge of the broader layer of stones, 1 By this term, we mean the northern lunistice occurring at which is different from all the others in size. It then the time of major standstill, i.e. the furthest northerly dec- becomes easy to count the number of illuminated rows lination ever reached by the moon.