SUNDIAL OF HADŽI ALI-BEG’S MOSQUE IN TRAVNIK

Author: Milutin Tadić, PhD, retired university professor • Photo: Mirza Hasanefendić

The sundial was built in next to the southwest corner of the Hadži Ali-bey Mosque, which is situated at Gornja čaršija in Travnik (Fig. 1). For decades, it was neglected and left to the ravages of time, both due to the widespread view that it was not constructed for the site it is at, and to the fact that, overshadowed by high surrounding trees, it does not work for most of the year. An article published in Zbornik radova Zavičajnog muzeja u Travniku in 1991 proved that it was not true. The article also warned that the sundial should urgently be put under the state protection, which was done in 2005, when the Hadži Ali-bey Mosque with the clock tower (and the sundial) was designated as a national monument of Bosnia and Herzegovina. Consequently, the sundial was retouched in the National Museum in Sarajevo in 2018 and built in at the same spot (Fig. 2).

Since exact testing determined that the sundial of the Hadži Ali-bey Mosque was both properly constructed and that it is a true example of a sundial constructed according to all rules of gnomonics, a question arises as to what could have created the fallacy about it as a clock positioned at a wrong spot. The most likely “culprit” is the alaturka hour system for which the sundial in Travnik was constructed. On contemporary wall sundials, the shadow of obliquely positioned long rod (polos) shows day hours with its direction, while on sundials for the alaturka system, the hours are shown by the end of the shadow of a short spike (orthognomon) orthogonally positioned on the plane of the wall, which intersects hour lines. Besides alaturka day hours counted from the previous sunset, twice from 1 to 12, the end of the spike shadow also shows astronomical beginnings of seasons, the Zuhr and the Asr. Since they did not know how to “watch” such a clock, uninformed viewers left convinced that the clock was wrong.

The gnomon grid of the sundial in Travnik is complex (Fig. 3). The grid is framed by a right-angle triangle, the sides of which are composed of the projection of arches of the horizon and the celestial meridian, while the hypotenuse is drawn in parallel to the projection of the arch of celestial equator, which is drawn between projections of the arches of celestial tropics, which are in turn shown as arches of the hyperbola. Every 15 minutes, hour lines (straight lines without a common pole) diverge at a slanted angle. The hour lines are intersected by the arch of the Asr line. Next to the framing hypotenuse a dial is carved, and it is composed of East Arabic digits from 5 to 12 (5, 6, 7, 8, 9, 10. 11, 12).  Day alaturka hours are read according to the position of the end of the shadow of the orthognomon between hour lines. If one adds 12 hours to the read alaturka time, one finds out the time which passed from the previous sunset, and if the read time is subtracted from 12 hours, the time which remains to the following sunset is obtained; if, in turn, one adds, to the read alaturka time, the time interval between the previous sunset and midnight, one obtains the alafranga time, according to which hours are counted from midnight. One should also keep in mind that the shadow on the sundial in Travnik shows the apparent solar time, while nowadays Central European Time, which is based on the mean solar time, is officially used.

During winter solstice, the end of the orthognomon shadow moves along the upper hyperbola and announces the astronomical beginning of winter, while during summer solstice the end of the shadow moves along the lower hyperbola and announces the astronomical beginning of summer; by moving along the projection of celestial equator the end of the shadow announced that the March/September equinox has arrived and that spring/fall begins, in the astronomical sense of the word. When the end of the shadow, entering the framing triangle of the grid, touches the projection of meridian, it is noon (Zuhr), while the position on the arched line between the hyperbolas signifies the beginning of Asr. This line pertains to the first Asr, the beginning of which is defined by the afternoon moment when the shadow of the man becomes equal to the sum of his height and the length of his noon shadow.

The sundial is most likely as old as the Hadži Ali-bey Mosque, which was built in 1866. Since the mosque was built at the site of the Mehmed-pasha Kukavica Mosque from 1757, which had been destroyed in the fire, it is not impossible that the sundial had survived the fire; however, there is no evidence for this assumption for the time being. It is also not known who constructed the sundial. It could have been one of local or Istanbul experts in practical astronomy. Among the locals, it could most likely have been Salih Sidki Hadžihusejnović (1825-1888.), the muwaqqit of the Gazi Husrev-bey Mosque in Sarajevo, who had all the knowledge and skills needed for the construction of a sundial such as the one in Travnik. Wihtout any doubt, the constructor had, as a model, a very similar (though far bigger) triangular sundial of the Fatih Mosque from 1771.

Today, there are many websites where it suffices to enter the place and the date to obtain the exact time according to alaturka system on the computer screen and find out beginnings of daily Islamic prayers. The viewer had the same information as early as 150 years ago, by casting a glance at the “screen” of the sundial in Travnik: the muwaqqit used the shadow as a reference for adjusting the clock mechanism on the clock tower of the Hadži Ali-bey Mosque; it silently let the muezzin know when he should make adhan to inhabitants of Gornja čaršija, while it allowed any passer-by to check or wind their pocket watches. It was true 150 years ago and it is true today: unlike digital watches, cell phones and tablets, the “battery” of sundials, one and only, is inexhaustible.  

Thus, the sundial of the Hadži Ali-bey Mosque in Travnik belongs to the group of wall triangular sundials; about thirty of such sundials have been preserved on old mosques in Istanbul. It was constructed for the alaturka hour system, accurately according to the latitude of Travnik and the azimuth of the mosque wall (according to the azimuth of the qibla of Travnik). By its exact content, accurate work, simplicity and beauty of graphic design, as Bašeskija would say, “it has no equal from Istanbul to Bihać”.

References

• Meyer, W.  (1985). İstanbul'daki Güneş Saatleri. Istanbul: Sandoz kültür yayinlari.

• Tadić, M. (1991). Stari sunčani sat Hadži Ali-begove džamije u Travniku. Zbornik radova Zavičajnog muzeja u Travniku, 4, pp. 33-48.

• Tadić, M. (2022). Gnomonika alaturka: sunčani satovi Hadži Ali-begove džamije u Travniku i Hadži Memijine džamije u Mostaru. Belgrade: Astronomical Society „Ruđer Bošković”.