NavList:

   

Reply

contact George Huxtable, at  george@hux.me.uk
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
----- Original Message -----
From: "Herbert Prinz" <666@poorherbert.org>
To: 
Sent: Friday, June 11, 2010 2:43 PM
Subject: [NavList] Re: NG's "Midnight Fun"


Herbert Prinz wrote

| So, if I understand correctly what George is saying, it's a combination
| of effects and the horizontal spacing of the sun images gives us a
| measure of how much is due to distortion.

Reply from George-

Yes: but those spacings, being mostly mostly in the radial direction from
the picture's centre, provide a measure of the local radial magnification
in that part of the picture.

The local circumferential magnification, which controls the apparent
height, would be expected to be much less; about a third of the radial
magnification, in the pinhole case.

George.

contact George Huxtable, at  george@hux.me.uk
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.


| George Huxtable wrote:
| > It's
| > clear that the gaps between the Sun images, nominally 5 degrees, are
| > increasing as they depart from the centre region
| >
| It did not notice this before. These gaps increase roughly in proportion
| to the height of the sun over the horizon.
| > Even after all this, the enhancement of the dimensions of the outer
Suns on
| > that picture seems even greater than the simple pinhole model would
| > predict.
| Exactly. This was the point of my comment to Peter. If we measured the
| height of the sun in multiples of its apparent diameter at each moment,
| the actual sun would be lower towards the edges than in the middle.
|
| So, if I understand correctly what George is saying, it's a combination
| of effects and the horizontal spacing of the sun images gives us a
| measure of how much is due to distortion.
|
| Herbert Prinz
|
|
|
|

   

Reply