Re: [Phys-l] optical center : real-life physics

[Bernard Cleyet <bernardcleyet@redshift.com>]

WallMart obviously doesn't have this:

http://findarticles.com/p/articles/mi_m0PIL/is_2005_Jan_25/ai_n8708132

When I worked for a IOL company we had a device that used four 
collimated pencils that gave the power of a lens including cylinder and 
prism.  It also found the "centre".  I've since seen it at 
ophthalmologists' offices. 

Before the LASER a common method was the place the lens in a rotating 
jig and look at a target off centre.  When it the image of the target 
doesn't move it's centred.  After the edge is then ground it may be 
mechanically centred by using two collinear tubes. The lens centres when 
squeezed between. 

I'm rather certain the principal axis intersects the centres of the 
lenses in a system, therefore, one may think of the centre of the system 
as the same as the intersection of the PA w/ any lens or just the PA.

bc, knows less, but has a library.

BTW, What the h .. was s/he doing in Wal*Mart?

John Denker wrote:

> On 06/11/2007 05:24 PM, alex brown wrote:
>  
>
> > What principles did you use to find the optical centre of the lens
> >    
>
>  
cut

>