A whitish ring, centred on the sun or moon, with a slightly bluish tinge on the inside and
reddish brown on the outside
Bishop's ring is due to the diffraction of light passing through a cloud of exceeding fine dust of
volcanic origin, which is occasionally present in the high atmosphere. The radius of the ring is
about 22 degrees.
The colours of a Bishop's ring are not very distinct; they are particularly faint in rings observed
around the moon, which usually shows only a pale red fringe.