This image is the result of aligning the stars in 32 separate calibrated light frames (registration) and then combining the 32 registered frames into a single image (stacking). While this process can be accomplished in Photoshop, it is extremely time consuming. I use Iris software for the calibration, registration and stacking processes. Iris is a very powerful, full-featured application designed specifically for astrophotography image processing. It supports raw image formats from most digital cameras and the author, Christian Buil, updates Iris frequently, adding new features and support for new camera image formats. And best of all, perhaps, is the price - Christian makes Iris software available at no charge.

Iris offers several different registration routines and many stacking algorithms. For this image I chose adaptive weighting as the stacking algorithm. Adaptive weighting uses a very complex mathematical approach to analyze the values of each pixel in each frame and produce a composite image that rejects aberrant pixels very effectively.

I also performed a preliminary white balance adjustment, and you can begin to see the nebula in this image. Most of the noise is gone, thanks to the adaptive stacking process. We're almost done now.