"Donut" code for aberration measurement from defocused images 

A.Tokovinin, April 29, 2005

--------------------------------------------------------------

Readme		This file

don11.pro	Main code
donut.common	Common block used in the main code
xd2.pro		GUI interface
ztools.pro	Zernike toolbox
readfits.pro	Auxiliary program from "astro" package
make.pro	"make-file"

donut.par	Example parameter file
focus.fits      Example image

----------------------------------------------------------------

Usage:

1. Edit the parameter file under suitable name, e.g. mypar.par

2. Compile the code under IDL: IDL>@make

3. Launch the GUI: IDL> xd, pfile='mypar.par'

In the GUI:

i) Load the image file <File>
ii) Select suitable star <Extract>
iii) Toggle the extra/intrafocal button depending on which side of the
focus the image was taken
iv) Fit the model <Fit> 
v) Save the Zernike coefficients <Save results>

Additional functionalities:

- Edit parameters: parameter editor. 

- Fit again: continue fitting, possibly with different number of terms

- Save static (ASCII file with Zernike high-order aberrations to
initialize the model)

- Save image: creates fit.ps with the picture of the image and model.

--------------------------------------------------------------------

WARNING: the code is not foolproof! Quite frequently, you will get an
error message of the kind:

% XMANAGER: Caught unexpected error from client application. Message follows...

Try to figure out what went wrong, close the GUI and start again!

----------------- end ---------------------------------------------