Reducing Noise in Milky Way Images
Explore Landscapes #37: Last week's paid post detailed my Milky Way Editing Workflow. Here's a little addition to that workflow on how to reduce noise in your images before you start editing.
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When using a high ISO for dark sky photography, you want to do all you can to reduce digital noise in your images. Assuming you’re not using a star tracker when photographing the Milky Way, you must push the ISO high to register sufficient light on the sensor and maintain spot stars (i.e., sharp stars that do not show the earth’s rotation).
To reduce digital noise, you can shoot batches of photographs of each of your Milky Way compositions and then combine these in software that uses multiple images to compute and reduce the digital noise.
I edit all my images on a Mac, so I use Starry Landscape Stacker. If you’re a PC user, then take a look at Sequator. This post shows the steps to reduce noise using Starry Landscape Stacker; the software interface looks a bit different on Sequator, but the steps should be broadly similar.
You take multiple images of the same composition (at least 10; more is better), each one of which is noisy, and then the software averages these images. The averaging process reduces the noise.