Strategies for Capturing Photographs During a Full Moon Phase

In the realm of digital astrophotography, the Full Moon presents a unique opportunity for capturing celestial objects that were previously unreachable during film-based methods requiring dark, New Moon skies. This article will delve into the strategies and tools used for successful Full Moon imaging and image processing.

During Full Moon, targets such as open and globular clusters, galaxies, star clouds, and emission nebulae using Hα filters become suitable for imaging. However, the blue color of the moonlit sky constrains the types of objects that can be successfully recorded. Blue reflection and planetary nebulae, comet gas tails, dark nebulae (or those with a low surface brightness), and targets with predominantly Oxygen-III (OIII) or Hydrogen-beta (Hβ) emission are less suitable. On the other hand, Hα and Sulfur-II filters are less affected by the blue moonlit sky.

One of the key aspects of Full Moon image processing is histogram analysis to correct for color imbalances and luminance bias introduced by moonlight. Tools like Capture One software are well-suited for removing the blue tint of moonlight in astrophotos and restricting luminance bias by using its advanced color editor and precise color balance tools to adjust hue, saturation, and brightness selectively.

Another software, Graxpert, is a freeware program that automates the alignment of histogram peaks, removes all gradients, and offers an AI denoise function, among other features. It can be downloaded from graxpert.com. After opening a raw stacked image in Graxpert, unselecting the "Channels linked" checkbox makes the program align the three color peaks in the image. Cropping out the black border is necessary to not confuse the AI flattening algorithm. Graxpert saves images as 32-bit TIFF files by default, but they can be changed to 16-bit if desired.

The AI flattening in Graxpert works great for most images, but complex nebulosity may produce dark areas or remove dim nebulosity. In such cases, the manual RBI (Relative Brightness Integration) method can be used. Hα data can be combined with RGB data to enhance images, preserving star color and adding nebulosity detail.

When it comes to image processing software, Adobe Photoshop and PixInsight are popular choices. In Photoshop, the goal is to align the tops of the peaks of all three color channels to remove the blue cast. PixInsight can make image processing easier by applying a linked screen stretch to the image before changing the individual histogram peaks.

In conclusion, Full Moon imaging in digital astrophotography presents a new dimension for capturing celestial objects. With the right tools and strategies, it is possible to overcome the challenges posed by the brighter and bluer sky during Full Moon, and produce stunning images that showcase the beauty of the cosmos.

Strategies for Capturing Photographs During a Full Moon Phase