GC 8/7/2020


An interactive simulation
of the Zeiss Diffraction Kit

  In the early 20th century many microscopists had difficulty understanding the diffraction theory of image formation in the microscope which Ernst Abbe had developed in the later years of the 19th century. To get the message across, Abbe's company, the great optics firm of Carl Zeiss, manufactured a teaching kit containing a special objective, a test slide and various 'tools'. The objective was mounted on a 'funnel' with a slit for inserting apertures or slits to modify which part of the diffraction pattern was able to contribute to the image. The Zeiss Diffraction Kit is both instructional and great fun to play with, but sadly it has now been out of production for many years.

Diffkit screenshot

  While on sabbatical at the University of Sydney, Professor James Pawley came up with the concept of making a computer simulation of the Diffraction Kit. The Australian Key Centre for Microscopy and Microanalysis provided sufficient funding to develop a prototype with a limited subset of the range of tools available on the original Kit.

  Our objective has been to keep things as close as possible to using an actual microscope. When you focus the image, the focus knob turns; when you insert the Bertrand lens, you see the slider go in. Other controls which were not suitably located for display in this way are shown as animated icons which reflect their actual shape and operation. The image plane and back focal plane are visible all the time and show what is happening. The images are real, captured from a microscope which was fitted with an original Zeiss Diffraction Kit.

Click here to run it in your Web browser. (Requires Flash player to be installed, and may not work after end 2020 since Adobe has announced an 'end of life' for Flash player.)


  The current version is available for free download.

Click here to download the PC version - a standalone executable requiring no installation or additional files. (3.81 MB)

Click here for the instructions and a non-technical introduction to diffraction and imaging. (26 KB)

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This page last updated on July 8, 2020

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