Sites change, they are born and they die. This is not a complete or necessarily up to date list.
Descriptions - explanations
of colour -
Bows & Haloes - Richard Fleet
Green Flashes - Andrew
Young definitive account
of a water drop Philip Laven
Auroral ovals & activity
image - Pekka Parviainen's definitive images
of the Atmosphere - Tomáš Tržický
Kaiser - NLC section
Atmospheric phenomena and sky - Jari Luomanen
Cloud Observer's Homepage Tom McEwan
pphv - Peter Paul Hattinga Verschure
Photography Harald Edens
Cloud Appreciation Society
Wikipedia articles on atmospheric optics are of variable reliability and best avoided.
Marvels of atmospheric optics feed through our eyes. Many hover close to the bright sun and
exceptional care must be taken to protect our most valuable sense. Always hide the sun
behind a tree or building. Never, ever, look directly at the sun and certainly not through binoculars
no matter how dim it appears in visible light. It can still be emitting copious retina burning infra-red.
Key tips to protect your vision - Gregory Miller