Optics: Technical, not piano - perhaps clutter

[Lance Lafargue]

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)