LDN 1622 - A Dark Nebula in the Foreground?
FSQ 106 / QSI683-wsg8
From free data on Deep Sky West Website
Processing: PixInsight, ACDSee, Topaz
Alex Woronow, 2021
Removing stars to enable extracting otherwise impossible to extract details seems like such a good idea, in theory. In practice, it’s a nightmare! Maybe the best way to remove stars so-far developed is StarNet. But it distorts the nebula around big stars that it partially leaves behind and often leaves a cross-hatched pattern where stars were removed. Putting the stars back after processing the nebula leads to unrecognizable PSFs and artifacts in and around the stars. Sometimes, these defects appear negligible, but that’s the exception for me. Does anyone have a better way that succeeds more than it fails and allows one to extract all the details in the nebulae we treat?
I have seen the PS scratch-removal method, but it demolishes fine detail, even when the “tone mapping” procedures are followed, thus defeating the purpose of star-removal for detail enhancement.
LDN 1622 is the dark nebula at the image center of this almost 2deg wide image. The wealth of nebulae in Orion, particularly the Orion-B complex, may include this object. However, some evidence suggests it lies closer to us than the Orion-B complex (400-500kpc) and be at a distance of only 160-200kpc and is not part of that complex (Knude and Fabricicus, 2020).
You can see the relationship of Orion-=B and other features in Orion in this illustration:
(Wikipedia)
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