A forum for scientific discussion of optical phenomena in the atmosphere and the natural environment,
sponsored by the Optical Technology Center at Montana State University in Bozeman, Montana.

Contributed and invited oral presentations addressed original research on natural optical phenomena, emphasizing optics in the atmosphere. Topics include rainbows, halos, glories, coronas, iridescence, sky colors, mirages and refraction effects, contrast phenomena, optics of lightning phenomena, auroras, noctilucent clouds, visibility, light pillars, glitter patterns, and generally light scattering phenomena in the atmosphere and natural environment. We also had several presentations on educational web pages and novel observing and measurement techniques. Some interesting new topics this year were snow crystals and sky colors related to nocturnal insect vision. A one-day excursion to Yellowstone National Park on 27 June was a highlight of the week! 

"Pretty Picture" session: We continued the tradition of holding an evening session where all participants shared photographs and videos of natural optical phenomena. This session was chaired by Dr. David Lynch.

Lord Rayleigh Prize: This award was presented to Dr. Robert Greenler and Dr. David Lynch for their creative contributions and leadership to the field of light and color in the open air. Both recipients are authors of several leading books in this field and have been pioneering researchers in this field since the beginning of this meeting series in 1978. The prize was a small toy model of a milk truck, labeled with "fresh milk from Lord Rayleigh's farms," ... referring to the Rayleigh dairy that provided financial support so that John William Strutt, 3rd Baron Rayleigh, and his son, Robert John Strutt, 4th Baron Rayleigh, could focus on their scientific studies.