The following is a PostScript document. As such, you will need a program that can view this file type.
The purpose of this document (courtesy of Joseph Mack) is to see how well your telescope can resolve closely spaced lines and circles. Using some math described in the document, one can determine how many arcseconds the lines and circles are equal to.
Click on the image below to download the 14KB file
Starlight Express HX516 CCD image of test pattern from 40 feet away