Screenshot of the fgui interface.


An IDL program that computes and displays the effect of adding phase aberrations for apertures of different shapes. The phase aberration can either be Kolmogorov turbulence or decomposed into zernike modes. The program will display the PSF, MTF, and phase map. It can also convolve the aberrated PSF with grayscale TIFF images. The wavefront measurements of the eyes measured at CfAO Summer School can also be loaded using this program.

NOTE: this program is provided for EDUCATIONAL use only. It has not been tested for research purposes. This program comes without any support.


2010-08-17 : Version 1.2 from AO Summer School 2010 Download.

2009-08-18 : Version 1.1 with bug fixes and including new features in the display GUI. Download.

2008-08-15 : Version 1.0 - Download


For those with licenses for IDL 6.0 or greater:

  • Go to the directory that was uncompressed into.
  • Start IDL in that directory.
  • Type: fgui

For those without an IDL license:

  • Download the correct IDL Virtual Machine for your operating system, which is freely available as part of the trial version of IDL (free registration with the site may be required for download).
  • Install the downloaded file.
  • Start IDL VM (NOTE: do not start IDL or IDLDE).
  • A file dialog box should now pop up. Navigate to the directory where you uncompressed
  • Choose the file:fgui.sav and fgui should start

PSF of a hexagonal aperture
with no phase aberrations.

Usage Notes

  • Select aperature shape and pupil size, then either introduce phase aberrations using the phase screen or through zernike modes. Click on the 'Calculate' button to calculate the PSF, MTF, and to show the phase map.
  • The 'Calculate' button must be clicked to update the display after changes to either the Zernikes slider or the phase error slider.
  • If the pixel values in the display windows exceed the values allowed by the slider bars, just close the window and click 'calculate' again to remake the window with a higher maximum value.
  • The wavefront measurements taken at the CfAO summer school can be loaded through the 'File' menu.
  • Convolution of a PSF with a grayscale TIFF image can also be done by loading the image in the 'File' menu.


  • - Tuan Do (UCLA), Mike Fitzgerald (LLNL), Luke Johnson (UCSC)
  • and associated procedures - Don Gavel
  • - Liam Gumley
  • Also contains procedures from the IDL Astro-library.


Questions or comments: Tuan Do (tdo [at]


This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.