The Moon showed yellow, red and many colours: Bartholomew de Cotton on the eclipse of 22 October 1287
Bartholomew de Cotton, monk of Norwich, as quoted in Guillet et al. 2023: 'Eodem anno luna in plenilunio visa est crocei, rubei ac varii colori', the same year, at full Moon, the Moon was seen yellow, red and of many colours. Two Italian sources agree. A bright, colourful eclipse means a clear stratosphere, which is the puzzle for the 1286 eruption.
How it connects
This clue from people argues against
Antarctic sulfate spike, about 1286 no northern veil by October 1287
This clue from people supports this hunch
The 1286 eruption really happened in 1285
This clue from people is a clue for
1286 eruption: a big sulfur signal that left the Moon bright
This clue from people we read it in
Guillet et al. 2023, Lunar eclipses illuminate timing and climate impact of medieval volcanism, Nature 616, 90 to 95 (open access)
This clue from people came from this step
Checked the 2023 eclipse study for our medieval eruptions, and corrected two mistakes