Gravitational Lensing on the Web

• http://cfa-www.harvard.edu/castles
  
  A database of real astronomical gravitational lenses. The page has a table of known lenses, with a thumbnail image of each one. Click on any lens to see more detailed pictures. All of the pictures are from the Hubble Space Telescope.
  
  
• http://oposite.stsci.edu/pubinfo/PR/2001/32/index.htm
  http://oposite.stsci.edu/pubinfo/PR/1999/18/index.html
  http://oposite.stsci.edu/pubinfo/PR/96/10/A.html
  
  Press releases from the Space Telescope Science Institute.
  
  
• http://www.ams.org/new-in-math/cover/grav_lens.html
  
  A nice introduction to gravitational lensing, with some good illustrations.
  
  
• http://www.iam.ubc.ca/~newbury/lenses/lenses.html
  
  Background information and simple examples. Click on "Critical Lines and Caustics" for a nice simulation, and click on "Lens Modeling" for a lens you can play with.
  
  
• http://theory2.phys.cwru.edu/~pete/GravitationalLens/GravitationalLens.html
  
  See Mike Turner lensed! Click on the tab marked "default" and choose "Turner". Click somewhere in the right-hand picture to place the gravitational lens. Then click the "2*mass" button 6 or 7 times to increase the mass of the lens. You can then click around in the right- hand picture to move the lens.