Archaeological Discovery, 2015, 3, 40-50
Published Online January 2015 in SciRes. http://www.scirp.org/journal/ad
http://dx.doi.org/10.4236/ad.2015.31005
How to cite this paper: De Lorenzis, A., & Orofino, V. (2015). New Possible Astronomic Alignments at the Megalithic Site of
Göbekli Tepe, Turkey. Archaeological Discovery, 3, 40-50. http://dx.doi.org/10.4236/ad.2015.31005
New Possible Astronomic Alignments at the
Megalithic Site of Göbekli Tepe, Turkey
Alessandro De Lorenzis, Vincenzo Orofino*
Dipartimento di Matematica e Fisica “E. De Giorgi”, Università del Salento, Lecce, Italy
Email: ale7delo@hotmail.it, *vincenzo.orofino@unisalento.it
Received 3 January 2015; accepted 22 January 2015; published 26 January 2015
Copyright © 2015 by authors and Scientific Research Publishing Inc.
This work is licensed under the Creative Commons Attribution International License (CC BY).
http://creativecommons.org/licenses/by/4.0/
Abstract
Göbekli Tepe is the oldest and one of the most important among the megalithic sites in the world.
Its archaeoastronomical relevance has been recently evidenced by Collins (2013), according to
whom the central pillars in four of the enclosures discovered in the site are oriented toward the
setting point of the star Deneb (α Cyg), as this point moves in the course of the time, due to the
equinox precession and the proper motion of the star. Taking into account these effects, Collins
(2013) obtained an astronomical dating for the various enclosures which agrees rather well with
the one obtained by Dietrich (2011) with the technique of carbon-14. In the present paper the
careful evaluation of the effects caused by atmospheric extinction has enabled us to verify that the
central pillars of the studied enclosures are in fact turned to face the setting point of Deneb, but
these alignments occurred in epochs, still in agreement with the ones obtained by Dietrich (2011),
but different from those proposed by Collins (2013). We have also individuated, for the first time,
the probable astronomic alignments of two other enclosures at Göbekli Tepe, i.e. enclosures F and
A. In particular, the first one seems to be oriented towards the rising point of the Sun on the day of
the Harvest Festival, a day approximately halfway between the summer solstice and the autumn
equinox. The second one, instead, shows an orientation towards the rising point of the Moon at its
minor standstill. The positions of both celestial bodies have been obtained by extrapolating their
declination to the date of the presumed construction reported by Dietrich (2011). A short discus-
sion about the putative cultural motivations of these alignments is also presented.
Keywords
Megalithic Temples, Archaeoastronomy, Astronomic Alignments, Harvest Festival, Lunar Standstill
1. Introduction
A conspicuous part of archaeoastronomical research is aimed at individuating the possible alignments that some
*Corresponding author.
A. De Lorenzis, V. Orofino
41
megalithic complexes, built all over the world by ancient civilizations, might present with regard to the position
occupied in the sky by some celestial objects. There are numerous instances of sets of stones, or single structures,
oriented towards the point where the Sun (Calledda & Proverbio, 2004; Magli, 2009), the Moon (Ruggles, 1985;
Ruggles & Burl, 1985; Magli, 2009), or bright stars or clusters of stars (North, 1996; Calledda & Proverbio,
2004; Zedda & Belmonte, 2004; Belmonte, Shaltout, & Fekri, 2008; Magli, 2009), rose or set in particular days,
often related to religious festivals or agricultural events. And this applies also to the oldest megalithic site in the
world, Göbekli Tepe, that stands on the summit of a hill of 780 m in height, at about 13 km north-east of the city
of Şanlıurfa, Turkey. Probably built during the second half of the tenth millennium BC, during the PPNA (Pre-
Pottery Neolithic A, 9800-8700 BC—Dietrich, 2011) period, the monumental complex dates back to 7000 years
before Stonehenge and the great Egyptian pyramids of Giza.
The archaeological site of Göbekli Tepe is made up of a series of rings or enclosures (about 20, of which 16
underground and 4 excavated). The first enclosures to be found were assigned the letters A, B, C and D accord-
ing to the order of their discovery. Later more enclosures were found and indicated with successive letters of the
alphabet: of particular interest are the E, F and G enclosures, although they do not boast the same monumental
character of the first four (Schmidt, 2010). The main feature they have in common is the presence at the centre
of each of two enormous, T-shaped monolithic limestone pillars, of a height of between 3 and 6 meters, sur-
rounded by other pillars of the same shape but not as tall as the central ones, set out around the enclosure wall.
Enclosures E and F only have the couple of central pillars.
The T-shaped pillars have been worked on with meticulous care by the site’s creators, if we are to go by the
presence of numerous, well delineated figures carved into these structures: abstract symbols, but also numerous
animals (foxes, lions, oxen, hyenas, scorpions, spiders, various reptiles, insects and birds, especially vultures).
Figure 1 illustrates a reconstruction of the plan of the site.
Figure 1. Plan of Göbekli Tepe. Enclosures A, B, C and D are in the context, with enclosure E shown as a “satellite” because
of the fact that it is situated outside, towards the west, with respect to the main group of structures, known as “The Rock
Temple”. Enclosure F is also outside the main group. In the map, the steps discovered in 2012, to gain access to the site, are
also shown (Source: Hale & Collins, 2013).
A. De Lorenzis, V. Orofino
42
2. Archaeoastronomical Implications
What exactly were the enclosures of Göbekli Tepe plain for? And above all, were the T-shaped pillars aligned
towards a particular object in the sky? It has been suggested that the pillars pointed in the direction of Sirius
(Magli, 2013) or towards the constellations of Taurus or Orion and the clusters of the Pleiades (Schoch, 2012).
But these, like other interpretations, have been questioned by Collins (2013). It can be said with certainty that
the main candidate presenting orientations towards celestial bodies is the pair of central pillars present in each of
these structures. These pillars might be a sort of astronomical marker (Collins, 2013) since, at the time of their
construction it was possible to enjoy, from every enclosure, a view of the horizon without any artificial obstacles,
apart from the natural ones (mountains), free, therefore, in every direction, thanks to the height of the site (780
m a.s.l.).
3. Checking the Alignments towards Deneb (α Cygni) of Enclosures D, C, E and B
Collins (2013) has noticed that the central pillars in enclosures D, E, C and B are all oriented just west of north,
and, equally, just east of south (see Table 1). The author does not give any details about how the surveying was
carried out, so the azimuth bearings supplied must be considered to be affected by uncertainty of the order of at
least one degree. Of all the stars that populate the Northern skies (the only zone compatible with the orientation
of the pillars—Collins, 2013), the best candidate as the target of the central pillars, as chosen by the builders of
Göbekli Tepe was probably Deneb (α Cyg), the brightest star of the constellation of Cygnus, the Celestial Bird,
or Northern Cross. The movements of this star might well have struck these ancient populations because of its
rapid setting/rising cycle, i.e., its brief time interval (lasting a few hours in the same night) that passed between
the setting and the successive rising of the star, at the epoch when the enclosures were built. In fact, this particu-
lar behaviour of Deneb, almost like a circumpolar star, probably reminded the builders of the site of the cycle of
birth/death/rebirth that characterizes human life (Collins, 2013). Taking into consideration the effects of the
proper motion and the precession of the equinoxes on the position of Deneb in the course of the time, Collins
(2013) has proposed the dating presented in Table 1 for the various enclosures. He has based his calculations on
a value of the angle of extinction of Deneb fixed at 2 degrees, including the corrections for the refraction by
means of the Stellarium astronomical software.
These orientations and the relative dating proposed by Collins (2013) have been verified in this work by means
of the application of a new archaeoastronomical procedure. The study is based mainly on a careful evaluation of
the effects that atmospheric extinction has on the coordinates of a star, a factor which is often neglected in many
works of archaeoastronomical subject, thus leading to results which are often completely misleading (for a dis-
cussion of this subject, see Schaefer, 1993).
The phenomenon of atmospheric extinction plays a crucial role in the determination of the rising of a star; in
fact, a star becomes visible only when its height above the local astronomical horizon has already reached a
consistent value, known as height of prime visibility (HPV). Analogue considerations obviously hold for the set-
ting. The procedure we have followed to determine the new dating can be summarized into 5 basic steps (for the
details, see De Lorenzis, 2013):
1) calculation of the extinction coefficient by means of the use of data regarding humidity in the observation
site;
Table 1. Data relative to the four enclosures oriented towards Deneb. In the first column we find the name of the enclosure;
in the second column the orientation azimuth of the central pillars according to Collins (2013); in the third the date of the
presumed construction of the enclosures proposed by Collins (2013); in the fourth the dating proposed by us; in the fifth the
difference (Δ) between the two previous datings; in the sixth the HPV used in our research, as found by CDC; in the seventh
the rising azimuth of the star, also found by CDC.
Enclosure Azimuth (˚) Year Collins (BC) Year CDC (BC) Δ (Years) HPV CDC (˚) AZ Rising CDC (˚)
D 353 9400 9590 190 1.65 7.02
E 350 9290 9463 173 1.65 9.99
C 345 8980 9156 176 1.67 14.99
B 337 8245 8409 164 1.72 23.00
A. De Lorenzis, V. Orofino
43
2) calculation of the air mass passed through by the starlight and its extinction caused by the Earth’s atmos-
phere;
3) determination of the HPV of Deneb by means of the use of Bouguer’s law of attenuation;
4) checking of the possible presence of reliefs in the directions where the enclosures are oriented;
5) search for the date when the calculated value of HPV of Deneb is observed.
The last point has been addressed by means of the Cartes du Ciel (CDC) software (downloadable at
http://www.ap-i.net/skychart/it/start), which, unlike Stellarium, rightly takes into consideration the effects of the
precession of the equinoxes and the stars’ proper motions on the celestial coordinates even in very remote epochs.
The new dating obtained by this method is reported in Table 1.
If we attribute an error Δ(AZ) = ±1˚ to the azimuth measurements reported by Collins (2013), we are able to
define the period (obtained again by means of CDC software), in which it was possible to see Deneb set at an
azimuth that fell within the angular interval considered. This period is reported in Table 2 where it is compared
with the dating obtained by Dietrich (2011) by means of analysis of carbon-14.
We can therefore affirm that the hypothesis proposed by Collins (2013), according to which the builders of
Göbekli Tepe would have wanted to celebrate their beliefs by means of the setting/rising cycle of Deneb as an
allegory of the birth/death/rebirth cycle of human life, seems as plausible as the dating. The differences (typi-
cally about 200 years) between the dating obtained by us and that by Collins (2013) are mainly due to the dif-
ferent ways in which the effects of atmospheric extinction on the measurements of celestial coordinates are tak-
en into account in the two works. In addition, the difference shown in Table 1 is also the fruit of the use by Col-
lins (2013) of an astronomic software (Stellarium) which is not adequate in evaluating the positions of the stars
in remote past epochs, as has already been demonstrated (De Lorenzis, 2011).
To complete the description of the site, we have to determine the possible alignments of enclosures A and F,
which we still have very little information about, both as far as regards their orientation and their dating.
4. The Alignment of Enclosure F towards the Sun
The only information available on the orientation of enclosure F comes by way of Collins (2013), who indicates
a disposition of the central pillars of the enclosure towards east-northeast or towards west-southwest, directions,
according to the author, which are very close to that of the Sun rising at the summer solstice or setting at the
winter solstice, respectively. Regarding this, Collins (2013) does not supply any numerical data, but, by a simple
geometrical calculation, it can be estimated that the azimuth relative to the first possible orientation is equal to
about 67˚ - 68˚ (N67.5˚E) and that relative to the second orientation about 247˚ - 248˚ (S67.5˚W); both the val-
ues can be affected by a minimal uncertainty of a few degrees.
Collins’ work also lacks an indication of the possible date of the building of the enclosure. An analysis using
the carbon-14 technique carried out by Dietrich (2011) on some bone and apatite samples found in the enclosure
supplies an indicative dating going back to circa 8380 BC. Evidently, as Dietrich (2011) himself maintains, this,
like the other dating obtained through analysis with carbon-14 for the other enclosures at Göbekli Tepe, is only
indicative. In fact, the embryonic state in which the archaeological excavation works carried out at the mega-
lithic site find themselves today, while work is in progress, cannot give this dating a definitive or absolute cha-
racter and should therefore be considered as preliminary (Dietrich, 2011).
On looking for the day of the year when, in the present epoch, the Sun rises (or sets) at an azimuth of about
Table 2. Comparison between the dating derived for the various enclosures by Dietrich (2011) with the technique of carbon-
14 and those obtained by us (using CDC) and by Collins (2013). In the third column we see the time interval within which the
setting azimuth of Deneb is found within a range of ±1˚ from the theoretical value reported in the fourth column of Table 1.
Enclosure Radiocarbon dating (BC) CDC dating (BC) Collins dating (BC)
D [9745; 9314] [9620; 9550] 9400
E [9500; 8500] [9510; 9410] 9290
C [9500; 8500] [9230; 9080] 8980
B [8306; 8236] [8520; 8210] 8245
A. De Lorenzis, V. Orofino
44
67˚ (or 247˚), it is possible to find an important date, associated with the Festival of Grain, or the Harvest Fes-
tival, a celebration which was particularly relevant for ancient civilizations because it sanctioned the moment of
the year’s first harvest (Keating, 1861). Today this feast (also known as Lughnasadh) is celebrated on 1st August,
that is about 41 days after the summer solstice, and is collocated approximately halfway between the summer
solstice and the autumn equinox. On this date, in fact, the rising azimuth of the Sun is equal to 66.5˚, which is
close to the orientation reported by Collins (2013), i.e. N67.5˚E. Very probably (see discussion in Section 6), the
builders of Göbekli Tepe had, amongst their main sources of sustenance, apart from hunting, the products of the
earth, as indicated by the findings in Layer I of the site reported by Dietrich (2011). So it is likely that they
wanted to celebrate this occasion by building one of the enclosures in the direction of the nascent Sun on this
particular day of the year.
We may therefore suppose that the central pillars of enclosure F are aligned in the direction of the sunrise on
the 41st day after the summer solstice, a day that we conventionally call the day of the Harvest Festival. To eva-
luate this hypothesis, a procedure, which can be summarized in the following points, was developed (for details,
see De Lorenzis, 2013):
1) individuation of the day on which the summer solstice took place in past epochs (by means of the CDC as-
tronomic software), taking into account the effects of the translation of the data due to the precession of the
equinoxes;
2) individuation of the day of the Harvest Festival (collocated 41 - 42 days after the summer solstice) in the
epochs studied;
3) determination of the azimuth of the rising Sun on the day of the Harvest Festival (obtained by the JPL Hori-
zons routine, see below);
4) reconstruction of the secular trend of the Sun’s azimuth on the day of the Harvest Festival;
5) extrapolation of the azimuth datum to the epoch of the building of enclosure F.
The reconstruction of the change over the centuries of the rising azimuth of the Sun on the day of the Harvest
Festival has been the result of careful research carried out by means of the generation of ephemerides by means
of the Horizons routine supplied by the NASA JPL, available at http://ssd.jpl.nasa.gov/horizons.cgi. To indivi-
duate this instant, we have adopted the widespread convention according to which the value of the rising azi-
muth of the Sun (and the Moon) is the one relative to the moment in which the upper limb of the object goes
past the horizon (Horizons User Manual, 2013). The time interval covered by the research ranges from 3000 BC
to 2505 AD, registering the rising azimuths of the Sun every 275 years starting from 3000 BC. This epoch, in
fact, represents the earliest limit for which we can calculate the ephemerides of the Sun (and of the Moon) in all
the available astronomical routines. The incomplete nature of the astronomical catalogues for very remote posi-
tions in the past and in the future depends on the behaviour of the Earth’s orbit. The Earth, in fact, is affected by
various gravitational perturbations due to the presence of the other planets of the solar system, distancing itself
slightly from the pure Keplerian motion. Although these perturbations are slight, over time they can bring about
effects which can be relevant.
As a matter of fact, the declination (and hence the rising azimuth) of the Sun on a given day, which is constant
year after year over relatively short time ranges (several centuries), can vary on much longer timescales. In ab-
sence of theoretical indications about this long-term secular trend, we have decided to interpolate and then
extrapolate the collected data about the rising azimuth of the Sun on the Harvest Festival by using three laws
which best fit the data: constant, linear (slightly) decreasing and parabolic. This extrapolation gives an estimate
of the rising azimuth at the presumed date of construction of enclosure F (approximated at 8400 BC) in the
range 66.2˚ - 67.6˚, with a most likely value of 67.6˚. The latter is obtained with a parabolic trend, which, with
its value of the reduced χ2 (Taylor, 1982) equal to 0.07, gives the best fit of the data.
The values extrapolated in this manner, however, cannot yet be compared with the azimuth of the central pil-
lars supplied by Collins (2013), since we have to take into account another important factor, which is the pres-
ence of reliefs in the zone surrounding the megalithic site. By means of Google Earth, it has been established
that in the direction previously individuated there is a relief of about 2116 m that means the field of vision of the
horizon surrounding the site is not free anymore. By applying a model of a flat surface, we obtain that the cor-
rection to make to the height of the sunrise is equal to Δh = +0.2˚ which, translated in terms of azimuth, corres-
ponds to a variation equal to Δ(AZ) = +0.2˚. Thus, the estimate for the azimuth of the sunrise at the time of the
presumed construction of enclosure F on the day of the Harvest Festival, corrected for the effect of the topogra-
phy surrounding the site is somewhere between 66.4˚ and 67.8˚, with the latter which represents the most likely










