Alaturka sundial of the Hadži Ali-bey mosque in Travnik

Alaturka sundial of the Hadži Ali-bey mosque in Travnik The only old sundial for an exclusively Alaturian clock system outside the borders of today's Turkey is located in Travnik (BiH), which for a century and a half (1699-1851) was the capital of The Eyalet of Bosnia and the residence of Bosnian viziers. It is located on the southwest wall of the Hadži Ali-bey mosque (44 ° 13 '34 "N, 17 ° 39' 36" E), named after its founder who built it in 1866 on the foundations of the old mosque from 1757, which was destroyed by fire. With a strange hour scale, shaded by the surrounding trees, the sundial was long forgotten. In 2018 the slab was retouched at the National Museum in Sarajevo. The contents are engraved on a tufa slab (97 x 73 cm) mounted into the mosque’s wall. The contents are engraved on a tufa slab (97 x 73 cm) mounted into the mosque’s wall. The Hour-scale is enclosed in a right triangle which legs are a = 65 cm and b = 49.5 cm. The scale consists of hour-lines, date lines (projections of celestial tropics and the celestial equator) and lines for noon and afternoon Islamic prayer. The lines for both prayers are marked with the appropriate signs. Hour-lines are precisely incised for every 15 minutes, with stylized endings. Ciferblat for the alaturca hours consists of East Arabic numerals from 5 to 12. The solstice hyperbolas and the line for asr prayer are also precisely engraved. The line for asr prayer refers to the first one, i.e. to the asr prayer whose start is determined as the moment when the shadow of the gnomon reaches a length equal to the sum of the lengths of the noon shadow and the height of the gnomon. Today, this asr prayer is practiced in mosques in Bosnia and Herzegovina. The metal orthognomon (d = 12,5 cm) is preserved in its place so that the sundial is in function throughout its existence. The orthognomon shadow’s end accurately shows the alaturca hours, as well as the beginnings of the noon and afternoon prayers. In regard of content and design, this sundial belongs to type of "triangular" sundials. It is equal to the best Istanbul sundials, both from its precision and artistic point of view. It was made by an experienced, top class gnomonist: one thing is certain, he was an experienced gnomonist, a master of his craft.