Ron, you were asking me in D.C. why I let Jim stay on the list.... Now you know. He's the list's refraction expert. B~) Lance Lafargue, RPT Mandeville, LA New Orleans Chapter lafargue@iamerica.net -----Original Message----- From: owner-pianotech@ptg.org [mailto:owner-pianotech@ptg.org]On Behalf Of JIMRPT@AOL.COM Sent: Thursday, July 13, 2000 12:06 AM To: pianotech@ptg.org Subject: Re: Optics: Technical, not piano - perhaps clutter In a message dated 7/13/2000 12:06:34 AM, Ron wrote: <<It's apparently a refraction thing, since the viewing angle was so narrow and definite. This really intrigues me, since it isn't obvious to me how it works, and is, indeed, downright wrong by what I think I know but is, at the same time, obviously real.>> Yep you are correct oh Sage, it is refraction. The same thing happens when you look down at the planes shadow on the ground and see a rainbow effect around the front edges of the shadow...this is also refraction effect from the compressed/bent air/water molecules on the leading edges.......on a big prop type plane, such as a C-130, the effect is most pronounced around the propellers themselves. This is most apparent when the sun is in the opposite position, relative to the plane that you describe..............your refraction though is coming from the moisture in the air (evaporating water) above those bodies of water and the operative angles are the suns position, the height above the body of water of the aircraft, and the position of the body of water elative to the aircraft. It is a prismatic effect and can be quite beautiful for as long as it lasts. <<" since the viewing angle was so narrow and definite. This really intrigues me, since it isn't obvious to me how it works">> Ron diagram this thingee out and you will find that the angles create a defacto prism but since you are in effect part of the prism in the aircraft, in effect being the Y tangent, the only thing you will see is a distinct brightening of the light. Jim Bryant (FL)
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