"The picture was taken just after 8.00am close to the summit of Snowdon, the highest mountain in Wales and England (1085 m).
On the path from Hafod Eryri down towards the South ridge I was suddenly confronted by a marvelous Brocken Spectre and Glory.
Unfortunately, by the time I got my camera out it had disappeared. So, I waited around in the freezing wind for about a quarter of an hour for gaps in the cloud covering the sun. This picture and a couple of others are the results from when it did momentarily shine through."
Glories, like many sky optics, are evanescent and needs be captured the instant they appear.
Images do not capture how glories shimmer and sparkle but Graham's picture has caught the delicacy of the first ring colours magnificently. Compare them with the Mie computation by IRIS at left. The calculation is exact but my translation of all the individual wavelength components into three monitor RGB values has left much to be desired!
Sunlight diffracted by mist droplets has created the glory.
The shadow or Brocken Spectre is a 3D tunnel of shadow cast through the mist. The rocks at left and right are casting similar shadow tubes that also appear to converge towards the antisolar point.