Okay, I have a time for us to play with:
The Rumeli Fortress is Rumeli Hisari on
this mapIt is on the western bank of the Bosporus and is near the northern bridge (there are two suspension bridges over the Bosporus). From the map, at the location of the fortress, the bank of the Bosporus runs almost perfectly north/south.
We see Uchenna rappelling down one side of a ten sided tower. From this picture of the
Tower we can see the exact same spot on the Tower where Uchenna is climbing (look at the arrangement of little windows in the stonework).
The eastern pylon of the northern suspension bridge is in the background. From
this picture we can see that Uchenna was on a side of the tower that is parallel to the banks of the Bosporus.
Using the video cap of Uchenna I see that the sun is shinning from the right and has created a shadow running up the side of the cylindrical part of the tower almost exactly at Uchenna’s location at the corner of two sides of the decahedron. Since Uchenna’s side is going north/south I figured the sun was coming from 18 degrees to the west of due south (one half of 36 degrees--360 divided by 10). That means a solar azimuth of 162 degrees. Using
Sun, Earth, Moon Applet I found that it had to be 10:46 am for the sun to have that azimuth on December 12th, 2004.
That’s my guess for when Uchenna does the rappel.