Ismail Fakirullah Tomb and its Light Refraction Mechanism
Ismail Fakirullah Tomb and the other two structures associated with the Light Refraction Mechanism are located within the district of Aydınlar (Tillo), Siirt. The Tomb was built after the death of Ismail Fakirullah by a student of his, Ibrahim Hakkı, in the 18th cent. The tomb stones date from the 19th cent. It has partially lost its authenticity due to misguided restoration works carried out in 1963. Ismail Fakirullah Tomb consists of two rooms and a hallway covered by one large and two small domes and a tower. The Tomb has a square plan covered by a dome. The transition to the dome is through squinches. There are two-level windows on all façades of the structure. The windows at the lower level have straight lintel with curved arched window pediment, while the windows at the upper level have a pointed arch span. There are also pointed arched pediment windows on the drums of the dome.
The main portal of the tomb opens to the entrance section which has a square plan covered by a dome, and from this entrance section it leads to the main section which also has a square plan. The interior sections of the tomb are plain in terms of ornamentation and include several other tombs other than Ismail Fakirullah.The tower, approx. 10 m. in height, next to the tomb has an octagonal plan.
Kalet‟ül üstad (a wall built of rubble, undressed stones of different size without any binding material), located on a hill overlooking the Botan Valley 3-4 km east of Tillo, is also important when considered in association with the tomb, tower and its light refraction mechanism. From its window opening of 0.40x0.50 cm wide, every year in 21st March (Novruz – or Nevruz, Nevroz, Nowrouz – inscribed in 2009 on the Representative List of the Intangible Cultural Heritage of Humanity) and 23rd September, the first light of the rising sun is reflected to the reflector precisely embedded in the tower of the tomb, and from a mechanism in the tower highlights the „sanduka‟ (eng.- „cenotaph‟) of Ismail Fakirullah.
The lightning starting from the lower left part of the Tac-ı Şerif continues for approx. 6 mins. In the first 3 mins., the Tac-ı Şerif is completely highlighted from the light reflected through the tower and in the remaining 3 mins. the light fades away in the opposite direction from the upper part of the Tac-ı Şerif.