CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
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chronological range that depends mainly on the magnitude of
the monument.
3. THE CHURCH OF THE GREAT METEORO
MONASTERY
3. 1 Historical Information
The "Meteora monastic community" is situated in the area of
Kalabaka in central Greece. It is the second biggest group of
Byzantine monuments in Greece. Today only six monasteries
are open, from the twenty that had been erected there in a period
of three centuries (14 th to 17 th ) (Sofianos, 1990). The Great
Meteoro Monastery is the biggest one and is founded at the top
of a rock, 588 m above mean sea level. The main church of the
monastery is dedicated to the "Transfiguration of our Lord"
which celebrates on August 6 th .
According to historical sources (Sofianos, 1990) the first small
building, which was located at the place of the church’s holy
altar of today, was erected in 1360 by Saint Athanasius the
Meteorist, who was the first inhabitant of this rock. After his
death in 1388, the monk Ioasaf enlarged the building and
erected the big church that exists today. This church is the
biggest of the Meteora monastic community and has all the
main characteristics of the late Byzantine architecture. The
building is 25.8 m in length and 10 m in width. The frescos on
the walls are dating from the 15 lh and 16 th century.
At the South-East side of the church a little chapel was founded,
dedicated to Saint John the Baptist and celebrating on January
7 th each year. According to (Theocharidis, P, 1979), this
building was constructed simultaneously with the main church
and, initially, it had some other use. Its length is 7.25m and
width 5m. It was converted to a chapel after the completion of
the big church.
3.2 Surveying the monument
A polygonometric network was established inside and outside
the monument, in order to survey it for a scale of 1:50. This
network consists of 12 points (figure 1) which are placed at
appropriate positions in order to measure all the detail - points
of the monument.
Figure 1. The polygonometric network.
The elements of the network were measured using the method
of the "three tripods", in order to eliminate the errors of centring
and levelling of the instruments. The measurements of the detail
points of the church were made using an integrated Total
Station that measures without retroreflector and has a laser
pointer, in order to mark each point accurately. The X, Y
coordinates of each point of the monument were determined
with an accuracy of ± 3 mm in the GGRS 87 (Greek Geodetic
Reference System 87).
The orthometric heights H of the points were also determined,
with a little lower accuracy (about ± 1 cm). The digital drawing
of the plan has all the details of the building. This plan is used
for the determination of the main axis of the church, as well as
for the extraction of any other geometric information of the
monument. The final plan of the monument is presented in
figure 2.
Figure 2. The plan of the two Churches
3.3 Determination of astronomical azimuth
The investigation of the orientation of a monument requires the
determination of the astronomical azimuth of a characteristic
direction of the monument. This direction may be the main axis
of the monument or another special direction, e.g. the direction
between the middle of the Holy altar and the middle of an
altar’s window or a specially placed line. For the determination
of the astronomical azimuth of these lines, the plan of the
monument needs to be astronomically oriented. This is achieved
by determining the astronomical azimuth of one side of the
polygonometric network, through astrogeodetic observations to
the Pole Star (Polaris, aUMi). In this case, the observations
consisted of 40 - 50 sightings of Polaris within 15 minutes,
which enabled the determination of the azimuth with an
accuracy of 0.5arcsec. This accuracy is much higher than the
one achieved by classical methods, with poles and compass.
The adjustment of the polygonometric network was done
holding the azimuth of this direction constant to the value of the
determined astronomical azimuth. Therefore, the plan of the
monument was oriented with regard to the astronomical north.
The astronomical observations were done using a new system
which was especially developed for the purpose and consisting
of a high accuracy digital total station, Leica TDM 5000,
connected to a Trimble 4000DL GPS receiver, providing
accurate UTC time. This system permits the determination of
the astronomical azimuth of a direction in short fieldwork time
and with high accuracy (Lambrou, 2003).
In order to study the orientation of the church of "the
Transfiguration of our Lord" two characteristic lines were
examined. The first was the main axis of the monument, joining
the middle of the holy altar with the middle of the main entrance
(at a distance of 22m). The astronomical azimuth of this axis
was found to be 119°34' ± O'.6.
The second line is inscribed on a flat marble stone, different
from all other flagstones (Picture 1), embedded on the floor in
the middle of the church.
