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Author Message   Glenn Tinkerer Username: Glenn Post Number: 608 Registered: 07-2006 Rating: N/A Votes: 0 Posted on Saturday, June 13, 2009 - 07:27 am:    The phenomenon of Newton's rings, is an interference pattern caused by the reflection of light between a spherical surface and an adjacent flat surface. When viewed with monochromatic light it appears as a series of concentric, alternating light and dark rings centered at the point of contact between the two surfaces. When viewed with white light, it forms a concentric ring pattern of rainbow colours because the different wavelengths of light interfere at different thicknesses of the air layer between the surfaces. The light rings are caused by constructive interference between the light rays reflected from both surfaces, while the dark rings are caused by destructive interference. The presence of the rings suggests that the rear, two element group, is air spaced. Beyond this I have no other thoughts, only to add that fungus does not produce this effect - well not in the many cases I have seen over the years.