Chuck, The original PDI (Perceived Depth Image- see: http://www.math.toronto.edu/~drorbn/papers/PDI/) images did use the eye-crossing method...where you focus at a point in front of the image. Most people found it difficult to train their eyes to do so...it took me several weeks before it 'popped'. Using the 'relax your gaze' method (focusing at a point beyond the image) on an image meant for 'eye crossing' will reverse the image. Foreground objects will appear behind others and vice-versa. When the Magic Eye books started coming out they reversed everything to make it easier for the masses...the focus point is beyond the image. To keep everyone on the same page they have also set up most stereo images to be viewed in the 'relax your gaze' mode. You'll find this to be true (unless your brain is doing something different than mine with the image) with the Wild 2/Stardust pair. Let me know what you really see trying it both ways. I definitely don't see the receding craters with the 'eye-crossing' method. Anyone else try this? Dave Bennett The On Monday, March 22, 2004, at 10:59 AM, Chuck Hards wrote:

http://skyandtelescope.com/news/article_1213_1.asp

The instructions posted for viewing without a stereo viewer are incorrect. Do not "relax your gaze as if staring through the screen into the distance". This is the procedure for viewing random-dot stereograms, not true photographic stereo pairs with recognizable details.

This is a true stereo image, not one of those red/blue "press release" jokes.

For true stereo pairs, you must consciously cross your eyes. The images then instantly overlap and you get the true 3-D effect. If you can't consciously cross your eyes then I guess you're out of luck in the absence of a viewer.

C.