The Photographer's Ephemeris (TPE) is a software giving, besides the direction of sunrise and sunset (yellow and orange), also the directions of moonrise and moonset (pale blue and dark blue). We use the reference point, shown by a pin in the images, at one end of the Decumanus. The dark blue line, which shows the direction of the moonset, is coincident to the Decumanus.
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About an interesting etymology of the name "Marsala"
