The weather produces Fraunhofer rings, too

[Weltevreden SA]

This Optics Picture of the Day (http://www.atoptics.co.uk/fz756.htm) image has a good discussion of the Babinet Principle, which states that diffraction patterns formed by an opaque shape are essentially the same as those formed by a circular aperture such as a telescope lens. The article is accompanied by some marvelous images of Airy discs and Fraunhofer rings formed in the sky.

[brian nordstrom]

:) Thanks Dana , those are nice photos .
Just a little out of focus on the rings , and a little CA aparent , :rofl: .
Nice .
Brian.