Descending to the river’s edge from beneath a sycamore tree near the Aswan Museum is the Nilometer of the Satet Temple (plaque number 10). Built in late Ptolemaic or early Roman times and restored in the 19th century, its staircase is roofed over and niches in the walls would have had oil lamps to provide light.
If you look carefully as you descend to the river, you can see the names of Roman prefects carved into the left-hand wall.