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Re: [Phys-l] lens combinations



C & J is evidently an Algebra based 1st year college text, and includes ray tracing. I suspect your more advanced students can learn quickly and use matrix optics. Then one may ask for the optical constants of various given lens combinations. Learning matrix Algebra is generally useful. e.g. eigen vectors of coupled oscillators. It took some time for physics texts to embrace this method common in engineering texts. Hecht now includes matrix analysis, as does Guenther. For analysis of "practical" systems, check out Nussbaum and Phillips. They analyze in detail the energy and optics of projection systems and telescopes in addition to telescope, Barlow and zoom lenses problems.

http://en.wikipedia.org/wiki/Ray_transfer_matrix_analysis


Note the matrix method is not limited to the paraxial approximation, as claimed by the wiki page above.




Probably all one need know:

http://www.bama.ua.edu/~ddesmet/id/index.shtml


bc, back in the early 80's matrix optics programmed a Sinclair computer (Z80).


On 2010, May 25, , at 07:23, John Denker wrote:

On 05/25/2010 04:58 AM, Anthony Lapinski wrote:
For my optics unit I am planning to do some lens combination problems in
my honors classes. Our textbook (Cutnell & Johnson) has typical, standard
problems. I am looking for more practical ones (involving actual devices)
for my students to try. For example, a telephoto lens basically consists
of a positive and negative lens combination.

That basically describes a Barlow lens
http://en.wikipedia.org/wiki/Barlow_lens

These things are commonly used in the amateur telescope community.
Ask around locally. It should be easy to lay hands on examples.

It is straightforward to find the design equations:
http://www.google.com/search?q=%22barlow+lens%22+equations
Example:
http://www.astunit.com/tutorials/barlow.htm

=========================

If you want something very real and very important, but involving
deeper physics than the above, consider compound lenses, such as
achromatic lenses
http://en.wikipedia.org/wiki/Lens_%28optics%29#Compound_lenses
http://en.wikipedia.org/wiki/Apochromat

To find the design equations:
http://www.google.com/search?q=achromat+"v-number";
http://www.google.com/search?q=achromat+"v-number"+site:.edu

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