LBN 251: Narrowband Structural Map

OTA:      Star-Fire 175 (f/8)
Camera:     FLI - PL16070AE
Observatory:     Deep Sky West

EXPOSURES:
    Hydrogen alpha:    24 x 1800 sec.
    Sulfur II:                   21 x 1800
    Oxygen III:              16 x 1800
        Total exposure:   30.5 hours

Image Width:    ~1.4 deg (N to the left)
FWHM (unstretched Lum) 2.8 pxl
Processed by Alex Woronow (2019-2021) using PixInsight, StarNet++, ImageJ, Topaz, SWT

This array of nebulae, bright and dark, lies in the constellation Cygnus. Very little information about any of these objects exists on the internet. Sorry! Should you know about or encounter a good description of the attributes of any of these objects, I would appreciate learning about your resource.

A 16bit display shows about 65500 colors, but some analyses of our ability to discern color differences on a screen suggest that somewhere around 256 colors can be distinguished--a significant disparity! In the medical imaging field, 'edge enhancement' (akin to contrast enhancement) helps accent very subtle gray-level changes in critical images. That is, edge enhancement accents structural detail present, but perhaps not otherwise obvious, in medical images. (BTW, artifacts are not an acceptable part of the edge-enhancement technology. "Look! A tumor--slice it out". "Oops! Sorry, it was just an artifact!" Not acceptable!)  I have used Canny edge-detection to reveal the structural detail in this active nebula--and there's a lot of subtle edges that are revealed! Nonetheless, because I removed the stars before using edge detection, there are artifacts around some of the brighter stars that become obvious when the stars are reinstated.

Not surprising that nebulae are structurally complex. I was once told in grad class, "the earth's atmosphere is turbulent at all scales." An emission nebula like this one has stars igniting and stars dying; both violent activities, magnetic fields swirling,  radiation ionizing the atoms, and shock waves everywhere. Indeed, these nebulae must make the earth's turbulent atmosphere look tranquil and featureless by comparison! I hope my image reveals some of the inevitable chaos inherent in giant emission nebulae.