Roman Scafe Sundial, Topkapi, Istanbul, Turkey
Posted by: 
arby101ca
N 41° 00.790 E 028° 59.082
35T E 666887 N 4542115
In the Third Courtyard of Topkapi Palace in Istanbul is another interesting historical sundial, a Roman Scafe sundial dating back to the 4th century.
Waymark Code: WM83BD
Location: Türkiye
Date Posted: 01/19/2010
Views: 19
Just across a walkway, to the south west of the horizontal Ottoman sundial is the Topkapi Roman Scafe sundial. The large stone is flat on top with a large sphere carved in the front. The south facing front is cut on an angle or scafe. The time lines are engraved on the circumference of the inner sphere. These lines are sloped from top left to lower right as it sits. They are quite different from the Roman sundial at Ephesus, a simple hemisphere with unequal hours and a horizontal gnomon. On the Topkapi dial the necessary point gnomon in the middle of the horizontal is missing.
As it sits this sundial is incomprehensible for most visitors including me. Perhaps if you flipped it over, tilted it up until the scafe surface was flat and oriented with the base of the scafe north it would work. In the equatorial plane with gnomon tip in the center of the sphere a shadow of the tip would trace the time each day, parallel to the tilted surface but moving up or down with the seasons and solar declination. Even hours based on noon would be straightforward, parallel to the noon line, with more hours in the summer than winter. But the engraved lines show 12 hours and noon shifts. Lay out 12 hours to sunset and you have the Italian hour lines for this sundial. The hours must be equal to give the slope and noon shift. It may average 12 hours but would show fewer in the winter and more in the summer. One odd line in the afternoon may be a crack in the rock or perhaps an Asr line added in Ottoman times. Further analysis is required and beyond the scope of this waymark.
Joel Robic's "Sundial of the Month" website linked below has further details and photos. On one you can see the Ottoman sundial in the lower left background.
Visit Instructions:
Only one log per location per person. You should log your own waymarked sundials as well.
GPS in photo optional.