Re: [ATM] ATM: Please answer simple question, each and every one of you, please-

["David Harbour" <stainless_steel@suddenlink.net>]

 Nils wrote:

>BTW when you look at your image by an ordinary flat mirror, how come
> it appears reversed left-right but not top-bottom?

The answer is, that only your eye makes the real image, and the real image 
is the one made only in your eye, when you look at yourself in a flat 
mirror. And remember, the scientists are not even sure why images made by 
the eye and are inverted on the retina, are rectified on the way to the 
brain. However, that is not the appropriate answer. The appropriate answer 
is this one:

Your reflection in a flat cosmetic mirror is not a real image; it is a 
virtual image, appearing below the mirror's surface. Stand in front of of a 
telescope mirror mounted in a tube, and back up far enough that you can see 
the inverted real image it makes of you, Nils. The image will not appear 
below the surface of the mirror, but in front of it; it is really there. It 
is an "aerial image" of Nils Olaf Carlin, and he will be, I guarantee to 
you, to the tune of maybe a million dreks, upside down: odd number of 
reflections, inverted, reversed. Try it. I demonstrated this many times to 
visitors to my optical shop. I would hold a card up for the telescope mirror 
to focus the scene outside the partly closed (so the garage was darkened) 
garage door, and one could clearly find the real image, way out in front of 
the telescope, and focus it on the card, simply by holding the little card 
in the right place in front of the mirror. Teh image was always inverted; 
since we were looking at it from the back side, on the card, and not from 
the front side, as if we used a ground glass, it did not look reversed, but 
it was- it depends on which side you see the real image fromThe rule is 
about image forming optics, not a cosmetic flat mirror. There has to be at 
least one image (real image) forming element in the train of flats; flats 
are not excluded from the rule, but the image forming objective must be 
involved. And- there is one when you look into the flat shaving mirror; 
only, the human eye disobeys (or should I say the human brain) disobeys the 
rule that things should be inverted. In any case, if the "software" in the 
brain were disabled, that rectified the inverted image in the eye, 
everything would look upside down.

In any case, I did not formulate the rule; I saw it in an atm-ing book, or 
in an article in Sky and Scope. I think if you will carefully, very 
carefully analyze this very complex train of reflections in your test set 
up, you will discover an error, and change your conclusions. I think the 
rule is akin to a formula in mathematics; I believe that it is as I said, 
"metaphorically"- set in stone (dental stone? Or Portland cement, the 
brilliant invention of the ancient Romans?)

R-101

----- Original Message ----- 
From: "Nils Olof Carlin" <nilsolof.carlin@telia.com>
To: <stainless_steel@suddenlink.net>; "ATM list" <atm@atmlist.net>
Sent: Monday, May 19, 2008 7:44 AM
Subject: Sv: [ATM] ATM: Please answer simple question, each and every one of 
you, please-


>
>>>>>
> Now, here is a rule, that I have seen, for which it is claimed that it
> is,
> shall we say, "metaphorically" "set in concrete". And the rule is
> this:
>
> (1): Odd number of reflections, image is reversed and inverted.
>
> (2); Even number of reflections, image is correct but inverted.
>
> This is for REAL  images, and not virtual images; it is for images
> that have
> been formed by a focusing objective mirror or lens, and then either
> had
> another single reflection, or not, or multiple reflections.
>
> A simple yes or no will suffice.
>>>>>>
>
> The last sentence is debatable ;-)
>
> For instance, when studying the reflections seen in a Newtonian when
> using an autocollimator, I found that after a grand total of 7
> reflections (counting reflections in the secondary), the real image of
> the primary's center spot, formed at the level of the primary, appears
> as if rotated by half a revolution (pi or 180 deg). This image is
> reflected back in the primary, and after another 7 reflections (making
> 15) it is reflected to another real image, accurately on top of, and
> oriented as, its origin.
>
> "Appears as", that is - but whether this orientation means it has
> rotated by 180 deg (clockwise or anti-) or has been flipped (or instead
> reflected) first top-down, then left-right (or in opposite order) is a
> matter of philosophic speculation. I guess "image is reversed and
> inverted" could apply to precisely this situation. But the process
> applied once more will restore the image orientation to the original
> one.
>
> http://web.telia.com/~u41105032/Acoll/Acoll.htm
>
> BTW when you look at your image by an ordinary flat mirror, how come
> it appears reversed left-right but not top-bottom?
>
> Wrong question. The image of you has its head up and feet down just
> like you have, its right arm to the right, its left arm to the left. It
> also faces the mirror just as you do - so, in fact, it isn't reversed
> at all.
>
> Nils Olof
>
>
>
>
>
> 


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