Gravitational Lensing 1.00
(c) Copyright 2001 - 2002 Kwakkelflap
Written by Maarten Vandenbroucke & Wouter Dhondt
Web: http://www.kwakkelflap.com
E-Mail: info@kwakkelflap.com

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Einstein's General Theory of Relativity demonstrates that a large mass
can deform spacetime and bend the path of light. So, a very massive
object, such as a cluster of galaxies can act as a gravitational lens. 
When light passes through the cluster from an object lying behind it, 
the light is bent and focused to produce an image or images of the source. 
The image may be magnified, distorted, or multiplied by the lens, 
depending upon the position of the source with respect to the lensing mass. 
The characteristics of the gravitationally lensed image depend upon the 
alignment of the observer, the lens and the background object. If the 
alignment is perfect, the resulting image is an Einstein Ring. With 
this program, one can draw images to see the effect of gravitational 
lensing. You can easily test the effects of several parameters by 
changing them and redrawing the image.

Send questions (and bug reports) 2 support@kwakkelflap.com

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Legal mumbo jumbo :

This program and the accompanying documentation are Copyright (C) 2001 - 2002
by Kwakkelflap.  You are allowed to redistribute it, provided that all 
the files in the original archive are distributed together and no changes
are made to any file in the distribution.  You can't charge for the 
program, only for distributing it.  You have to clearly identify us 
(Maarten Vandenbroucke & Wouter Dhondt) as the authors.

This program comes without any warranty either implied or expressed. In no
case shall the author be liable for any damage or unwanted behaviour of any
computer hardware and/or software.

The same things in English:

   - We own it.  It's ours.  Muahahaha!  (But we let you use it too.)

   - We can't guarantee that it works, or that it works correctly.

   - If it breaks, it's your fault.  But you do get to keep the pieces.

   - If it breaks something else, it's your fault too.

   - If you copy it, don't claim that you've made it yourself, or
     change it in any way; and copy both program and documentation.

   - You are free to offer the program on your web page.  All we ask for
     is that you give a link back to ours, and that you state that the
     program was made by Maarten Vandenbroucke & Wouter Dhondt

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Known bugs: none

Possible future enhancements:
- Scale on the view in arcsec

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Revision History:

Version 1.00 (24/05/2002)
- First release