ASTROPHOTOGRAPHY PROCESSING: Fix contrast extremes in your Moon shots

Use tone mapping to tame brightness and reclaim lost detail

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In Dave's shot of the Moon's southern highlands (left), crater Clavius was too dark, but he didn't want to lighten everything and blow out the brighter regions. Using Tone Mapping Persona in Affinity Photo (right), he drew out detail while keeping the bright areas in check

Capturing night-sky objects comes with its fair share of challenges. How you handle them can make the difference between a good image and a great one. Sometimes, when everything conspires against you getting a clean shot, post-processing is your only solution!

For example, with some deep-sky, narrowband solar, or lunar images, parts of the frame will be very bright, while others will be darker and less defined. In lunar shots especially, details near the terminator can be particularly faint due to small shadows created by a low-angle Sun. These reduce the overall brightness in that part of the image. Because it only affects one area, it’s not easy to achieve an exposure that will reveal faint details without blowing out the brighter regions farther from the terminator.

This image of the southern highlands around Clavius (above) is a good example.

While the brighter areas are almost overexposed, the capture settings were designed to prevent them from being completely blown out. However, the walled plain of Clavius on the left side of the image, where the Sun was rising, is still too dark.