Mirror Under Knife

Foucault Test Image Analyzer

0. Introduction
1. Download
2. Installation
3. Documentation
4. Acknowledgements

0. Introduction

Welcome to the homepage of Foucault Test Image Analyzer. If you are an amateur telescope maker, this software can take the tedium out of measuring the shape of your mirror.

Traditionally, amateur mirror makers use a Couder screen, nimble fingers and keen eyesight to quantify the results of the Foucault test by finding the exact knife locations where a zone is equally illuminated on the opposite sides of a mirror.

In this day and age, however, sophisticated illumination detectors (i.e. digital cameras) are inexpensive and readily available, thus eliminating the dependence on a highly subjective illumination comparison with the naked eye. This program, furthermore, eliminates the need for accurate knife position measurement. Simply take a sequence of photos at pre-set knife offsets, which need not be known with great accuracy, and let the software reduce the measurements and fit the theoretical illumination curves to best match the data.

These screenshots will give you an idea what measurement results look like.

1. Download

The latest release of the software is version 1.2. Here is the description of all the files in this release:

foucault-1.2-win-jre.exe Self-extracting Windows executable containing the program and everything needed to run it. Get this package unless you understand Java.
foucault-1.2.jar Just the program and supporting classes. You'll need Java to extract and run it. Get this package if you're using anything other than Windows.
foucault-example.zip A set of sample images of a not-so-good measurement, and some test images. Illustrates the points discussed in the documentation.

If you're interested in developing the software further, you can also visit the project page at sourceforge.net: http://sourceforge.net/projects/foucault/. There you can browse or download the sources, file bugs, etc.

2. Installation

3. Documentation

Instructions for using the program are available here.

4. Acknowledgments

This software uses optimization routines translated from Fortran by Steve Verrill <steve (at) ws13.fpl.fs.fed.us>, see this project. Thanks Steve.

All the graphics is done using the Scientific Graphics Toolkit from NOAA. Thanks Donald.

Project hosting generously provided by SourceForge.net Logo

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Maintained by Dejan Vucinic <dvucinic (at) users.sourceforge.net>
Last updated on May 14th, 2007.