How to blend images taken with different camera setups

Combine data captured at varied focal lengths to create rich, deep images

- 

Astrophotographers often return to the same targets to rephotograph them using different equipment. As a result, we often end up with multiple sets of frames captured with a range of focal lengths or camera sensors. Combining this data can produce stunning images that can be cropped in tightly to reveal intricate features.

One program that does this well is Astro Pixel Processor (APP), a powerful tool that easily blends multi-focal-length data in a few simple steps. Here I'll explain how to use APP to produce a high-resolution image, using my Whirlpool Galaxy image (above), made using data from two different imaging setups, including a triplet refractor and a Newtonian reflector.

Before opening APP, I went through each dataset of images and removed any frames containing plane trails, clouds or other unwanted elements. I also took dark and flat calibration images for each and saved the datasets into two folders.

When you first open APP, a window pops up asking you to select a working directory, the location where you have saved your data. If for any reason this does not pop up, click the 'Directory' button (highlighted, Screenshot 1) and navigate to your image folders.