On this day, a meridian altitude of the sun was taken, which shows 76[degrees]30'N as their most likely position.
If we take it that it was the upper rim of the sun that appeared in the SSE and disappeared in the SSW, the sun's meridian altitude would normally have been about 45', and the window of the duct would have had to extend over 1[degrees] above the horizon to make the upper limb fit inside it.