Animate Movement in Space nebula

The trick would be to separate the image into multiple layers in Photoshop using selection methods like Color Range. You could even combine multiple images. The images need to be about 2 to 3 times larger than your comp. Then you import as a composition retaining layer size, open the imported composition, Set the Comp Frame Size (HD, for example) and duration, then start animating rotation and scale. You'll need to adjust the anchor points using the Pan Behind tool (y) to bet the center of rotation around the center of the nebula. You might want to make the layers 3D to give some more interesting movement and parallax changes to the stars. 

The hardest part is going to be separating elements in Photoshop.  You can also do the work in After Effects, but I prefer the selection tools in Photoshop. 

Here's a pretty good tutorial on the workflow using AE: