LBN 251 (LBN 239, 236, LDN 880, B343) -- Narrowband

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) using PixInsight, StarNet++, ImageJ, etc.

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 just 65536 colors, but some analyses of the ability to tell color differences on a screen suggest that somewhere around 256 colors can be distinguished--an astounding discrepancy! 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 obvious, in medical images. (BTW, artifacts are not an acceptable part of the technology. “Look! A tumor. Oops! Sorry it’s 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 it! Nonetheless, because I removed the stars before using edge detection, there are artifacts around some of the brighter stars.

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, stars dying violently, magnetic fields swirling, radiation ionizing atoms, and shock-waves everywhere. Surely, 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.