The final step I perform in Iris software is called hyperbolic arc-sin stretching. This step enhances the colors and contrast in the faintest image areas while retaining the details in the brightest areas and keeping the noise under control. Hyperbolic arc-sin stretching is one of the most powerful features of Iris. While it is theoretically possible to achieve the same result in Photoshop, in practice it would be very difficult and extremely tedious. Iris performs this function in a matter of seconds.

For any Iris users reading this, the Iris command I used to stretch this image works for about 90 percent of the deep space astrophotography images I have processed:

>asinh 0.005,30

For the other 10 percent, adjustment of the two command parameters solves the problem. Check out the Iris website for detailed usage information.