SH2-155 framed close to the center in this image is a dense star-forming region of molecular cloud in Cepheus.  Judging from the number of items, especially young stellar objects (YSO) listed on Simbad and seen clustered around the "Cave" on Aladin, it is clear that scientists have put a lot of effort into studying this region.  It is likely that the very bright stars (the Cep OB3 association), along the N/S axis spine of the emission seen here in red, and also stars to the right of this axis (which is the edge of the Cepheus B cloud) are driving the molecular cloud away to the left with the intense radiation emitted.  Such light pressure also drives a compression of these clouds thereby increasing their density, which increases the rate of star formation.  The movement of this cloud front eventually exposes the new stars.  So position relative to this cloud front correlates with star age.  From our position on earth, imaging this object means we are looking pretty much right into the central spine of the Milky Way galaxy.  Though we are not looking toward the central dense part of our galaxy, still, there are likely no views here that can see through these foreground structures to space beyond, hence there are few if any background galaxies to be had.  I posted a Revision B of an image of our view of the dust in our galactic plane and the location of SH2-155 relative to this.

To me, this area is visually very interesting as well.  It is littered with interesting shapes, emission nebulae of widely varying intensity, reflection nebulae and combinations of both.  But perhaps more rare (and like what can be found around the Orion Nebula) there is a great deal of broadly scattered dust, of varying density that is not excited to emission to any degree, or even at all.  Some are strikingly silhoutted black in front of the emission components.  Or they becomes illuminated by closely associated stars to form a good deal of reflection nebulae scattered about.  A lot of the dust appears to reflect enough light to become visible as a smoky haze that dominates the whole left 2/3rds of the image.  The "Cave" itself appears to reveal both reflection and emission components.  But a significant portion of the molecular cloud appears as a layer of smoke of subtle colors in this OSC image that creates a great sense of depth of field.  Clearly where the clouds are more prevalent, there are less stars visible.  I believe the dust and field stars provide the viewer a better sense of depth of structure, even if our perception is wrong after all!  In fact, I find the starless version seen with the mouse-over has far less depth of field, so the stars are the more critical to our visual interpretation.

I include the full, uncropped image as a revision for those interested.

While the roots of this image go all the way back to July 2020, the amount of integration time in this image is more than doubled.  And I feel that the increased data increased image depth and also improvement in fine detail when new methods were applied warrant a separate post.  I have no idea why I left so much of the data I collected out of the original processing.  I should probably be taking notes when I image and processing these projects.  In fact I found a considerable amount of other data as well that is horrible and did not use it.  Why I saved that garbage, I also have no idea.  This was in my early days of astrophotography, and at this point I was still manually focusing.  In addition to the more than doubling the time in this image, the new xXTerminator tools made this job a great alternative distractin to my galaxys reprocessing effort.  I have to say, if I now imaged this object with my newer camera, I would not have done the things I did back then.  I likely would have used shorter subs than 300s and the newer camera might have squeezed a bit more out of the detail because of its pixel scale.  But I cannot deny that the old gear did a very nice job here.

I did run into some issues when using Noise XTerminator and Blur XTerminator.  For the darkest clouds seen in the image, using both of these tools caused most of these clouds to completely lose dynamic range.  Most of these clouds jumped to a value of essentially zero, creating a flat appearance.  Yet I knew these regions in the original stack had more to offer.  I wonder if anyone has seen this artifact when using these tools before?  My solution was to mask off these regions when applying NXT and BXT early in the processing.  I then inverted the mask and went back to Multiscale Medium Transform to deal with the noise within these clouds!  I never thought!....  Oddly, after stretching and doing most of the rest of the processing, I found that I could then use NXT late and reduce noise within these very same clouds without losing the nice gradients of darkness I wanted to preserve.  I would like to hear from others who might have had this issue and what they did to solve the problem.