Thanks guys! The 3d stereo pair is much cooler to view than the animation if you can do it.
Here is a high level description of the process :
1) remove all stars form your main image into a new starless version.
2) do an apply image -> subtraction from the main image with the starless one so you end up with a file that just the stars
3) Make a copy of the starless nebula image and make it greyscale and save as PSD
4) apply the filter "displace" 10-20 pixels horizontal only to the starless nebula doc using the greyscale "heat map" .. this basically converts B&W luminosity to depth .. white is far away, black is close.
5) Add your stars back in, in layers (e.g. faint stars on one layer, medium stars on another, big stars on another) and push them left or right if you want them closer or further. e.g. move a bright star 30 pixels to the right and it will seem very close to you.
6) The original image is the Left and the starless one you "displaced" and added the stars back in as layers becomes the Right image. Merge as a stereo document or Animated GIF
It's not very scientific but it sure is pretty
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