The contents of the window is a radial slice through each of the corrected extra-focal images, starting at the center of the image and ending at about 1.5 times the radius of the images. If the program has converged correctly, these two slices should for the most part lie on top of each other. High frequency aberrations which have not been removed from the images should cause the image intensity to rise in 1 extra-focal image, with a corresponding fall in the other image. You may use the slider to change the angle of the slice. Note that on optical systems with spiders you may see some high frequency noise in the region of the spiders. If your extra-focal image slices do not look well matched, this is a good indication that there was a problem with the data reduction.
It is also possible to review the intermediate calculation buffers. This is convenient if you suspect that you have a problem with your telescope specification. Select the Displays :: display buffer menu option. This will create a small sub-window which will allow you to review the contents of the program calculation buffers. Select the Corrected extra-focal image 1 radio button and then push the Display button. Next select the Right radio button of the Display destination line, then select the Pupil mask radio button and then push the Display button. After finishing these steps you should see a corrected image and binary pupil mask .
If everything is set up correctly, you should find that the corrected extra-focal image in the left hand display is approximately the same size as the pupil mask in the right hand display. The corrected image should also be round and fairly uniformly illuminated, some high frequency ripple is fine. If the extra-focal image is obviously smaller or larger than the pupil mask, then you probably have one or more incorrect values in your optical/program specifications. If there is an obvious size discrepancy, your derived wavefront is probably incorrect.