The 22 May 1453 eclipse was a partial one, rising at sunset over Constantinople
NASA catalog: partial lunar eclipse, umbral magnitude 0.745, greatest 17:16 UT, partial phase 178 minutes. In Constantinople sunset was about 19:25 local time, so the Moon rose already three quarters in shadow and looked like a crescent; the eclipse ended about 20:40, roughly 75 minutes after sunset. This explains Barbaro's 'three-day Moon' without any volcano. It was not a total eclipse, so its darkness cannot be used to test for a veil.
How it connects
This clue from nature is a clue for
The mystery eruption of 1452/53 and the omens at the fall of Constantinople
This clue from nature explains
Barbaro: the full Moon rose like a three-day Moon, and the air was clear as crystal, 22 May 1453 the crescent at moonrise is the partial eclipse
This clue from nature we read it in
NASA five-millennium catalog of lunar eclipses, 1401 to 1500 (Espenak and Meeus)
This clue from nature came from this step
Checked the Constantinople omens of May 1453 against the sky and the weather