Using Narrowband normalisation and more

The narrowband data were captured by AstroDMx Capture with a QHY Minicam8, and a William Optics 81mm APO refractor with a 0.8 reducer/flattener.

Using Narrowband normalisation on a starless SHO image and blending it back with the SHO image. Also using Seti Astro's NB to RGB Star Combination. to produce realistic RGB star images from narrowband star images.

Pixinsight was used to stack and register the S2, Ha and O3 data. Register the stars in the three monochrome images, remove the stars from the monochrome images and produce star images; delinearise the monochrome starless images; combine the S2, Ha and O3 images into an SHO false colour image; apply the PixInsight Process of Narrowband normalisation; generate ‘RGB’ star images with Seti Astro’s NB to RGB Star Combination script with default green adjustment; denoise and sharpen the starless images.

Gimp3 was used to adjust the levels of the SHO and the Narrowband normalised starless images to the same extent and to blend the SHO and Narrowband normalised starless images. SetiAstroSuitePro was used for Texture and Clarity processing of the starless images. Gimp3 was used to screen back the stars and SetiAstroSuitePro was used to apply Cosmic Clarity stellar and non stellar sharpening and denoising.

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Animation showing the SHO image, the Narrowband normalised for SHO image and the blend of the two images

SHO image

Narrowband normalised for SHO image

Blend of SHO and Narrowband normalised for SHO images

Using a blend of the SHO and narrowband normalised images helps produce a Hubble palette with more subtle colours than the narrowband normalised image alone. The image above is a 50%-50% blend but other proportions of each image could have been used to produce the desired colouration.

Steve Wainwright and Nicola Mackin