Középkori légköroptika - 4. lecke

Ez a kép elég késői. Lancashire-ből 1648 március 4-én Jeremiah Shakerley a következőképpen írta le egy 22° halo, 2 melléknap és a zenit körüli ív megjelenését:

This is a relatively late picture. Jeremiah Shakerley wrote the following letter on 4th March 1648 from Lancashire, describing a 22° halo, 2 parhelia and a circumzenithal arc:

"On Monday the 28th of February last, there arose with the Sun two Parelii, on either side one; their distance from him was by estimation, about ten degrees; they continued still of the same distance from the Zenith, or height above the Horizon, that the Sun did; and from the parts averse to the Sun, there seemed to issue out certain bright rays, not unlike those which the Sun sendeth from behind a cloud, but brighter. The parts of these Parelii which were toward the Sun, were of a mixt colour, wherein green and red were most predominant: A little above them was a thin Rainbow, scarcely discernible, of a bright colour, with the concave towards the Sun, and the ends thereof seeming to touch the Parelii: Above that, in a clear diaphanous ayre [air], appeared another conspicuous Rainbow, beautified with divers colours; it was as neer as I could discern to the Zenith; it seemed of something a lesser radius that the other, they being back to back, yet a pretty way between: At or neer the apparent time of the full Moon, they vanished, leaving abundance of terror and amazement in those that saw them."