NGC 2467 (Butterfly Nebula) HOORGB w/ RGB Stars and H Luminance

OTA:……………….TAO 150 (f/7.3)

Camera:………….FLI - ML16200 (1.13 arcsec/pixel)

Observatory:….Deep Sky West, Chile

EXPOSURES:



EXPOSURES:

…R……15 x 800 sec.

…B…...13 x800

…G……17 x 800

…O.……6 x 1800

…H.….10 x 1800

Total exposure 17.5 hours

Image Width: 1.3 deg

Processed by Alex Woronow (2020) using PixInsight, Topaz, 3DLut, SWT

Processing: The unique attribute of the processioning of this image is the handling of the narrowband images. A PixInsight Script (TrueColor-Plus SHORGB) I developed, and am testing before release, removes the background-radiation component, and leaves an estimate of the “pure” emission-line component. Every narrowband filer extends beyond the width of the emission line it targets, admitting unwanted signal (let’s call it background or noise). In addition, the wavelength span of the line is not solely caused by the target emission line. Other atoms, ions, molecules, and free-free transitions contributed to that same wavelength, further polluting the background's emission line.

My script makes isolates the emission line from the background, keeping the former and discarding the latter. This image was formed from the emission-line components only. Furthermore, the Ha line was used as the luminance component in the image because it has the most structural detail. The resulting image is in version B. RGB stars were sparingly added into the image, and a portion of the RGB image gave this version of the image.

NGC 2468: This poor nebula also goes by the name “Skull and Crossbones Nebula” and “Mandrill Nebula.” It looks more like a butterfly to me and even more like a star-forming hydrogen cloud. Within it lie several distinct young-star groups. One of the most prominent, not surprisingly, lies in the brightest region of the nebula (the whitish part) and features a massive young star HD 64315. Two clusters of note are H18 and H19. H19 lies in the circular-cloud feature just below the center. And H18 lies just above that. H19 is Strömgren Sphere, a region of ionized hydrogen (HII) around a young and very hot star. The Rosette Nebula is one of these beasts. The sphere consists almost entirely of free protons and electrons and a small number of hydrogen atoms. (Wikipedia…thanks.)