ABSTRACT
Ionized gases immediately suggest using narrowband filters and a quick perusal of other M27 images on the Internet confirmed it is largely formed from Ha and OIII and with subtle SII content. This assignment then became a good subject to show how to process a bi-color narrowband image. This chapter examines the luminance and narrowband files for these attributes and decide whether luminance acquisition through a clear filter is a good use of imaging time. The acquisition occurred during an unusually clear spell, and aimed to capture many hours of L, Ha and OIII, as well as a few hours of RGB for star color correction. It was a lesson in gainful luminance-data capture. Fine Tuning image required further improvement to star color, background levels, sharpening, color saturation, noise reduction, and star size. The RGB channels were combined and tuned for star color before being linear-fitted to the nebula RGB image.
