Re: [ATM] mirror or lens?

[aplanatic@aol.com]

 Hi Mike, 
 
The generally accepted astrophysics definition of the periodic table: H, He, metals.  (Willy Fowler, please forgive me.)
 
I find the physical difference between reflection and refraction quite significant, having to do with the availability of conduction electrons, among other things.  From a solid state physics point of view the two phenomenon are quite different, and would not even be covered in the same chapter...  In other words, it's a matter of view point.
 
-- Dave
 
-----Original Message-----
From: Michael Peck <mpeck1@ix.netcom.com>
To: atm@atmlist.net
Sent: Mon, 01 Aug 2005 13:32:37 -0500
Subject: Re: [ATM] mirror or lens?


At 12:40 8/1/05, Mike Lockwood wrote: 
>>And one of the family members said, "A mirror is still a >>lens." And he's an astrophysicist, and who really wants to argue >>with an astrophysicist? So I didn't knwo what to say. 
> 
>I think I would have said that lenses work according on the law of >refraction, while mirrors work according the law of reflection. Let >him rebut that. He can't tell you they're versions of the same >phenomena, because they're not. 
> 
 
The "law of refraction" and the "law of reflection" are both derived from Fermat's principle (http://scienceworld.wolfram.com/physics/FermatsPrinciple.html). Modern optical design doesn't really distinguish between reflective and refractive surfaces in any fundamental way, which is why you can use Zemax, OSLO et al. for both. 
 
Astrophysicists may not know much about optics in general, but in this case the astrophysicist was correct. 
 
Mike Peck 
 
_________________ 
 
Michael Peck 
email mpeck1@ix.netcom.com 
Wildlife photoblog! http://wildlife-pix.com 
Amateur telescope making http://home.earthlink.net/~mlpeck54/astro/astro.html  
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