Revised 3/2023:
First, as I explain in the second paragraph, I processed this with the intent of fixing and improving some minor issues, but it quickly devolved into my trying to extract as much information as I could, though maybe not end up with as aesthetic a result as the previous versions!  To that end, the mouseover highlights two features that I could not find any references too through the sources I checked.  First on the lower left corner is highlighted a red feature, on a background of red that appears to be circular, except a bite out of it at 12 o'clock.  Being red, I figured that it was just an extension of nebula features that happen to be sticking up at this location.  Checking the dust structure in Aladin long wave IR images does not seem to support that.  Most of the dark features nearby seem to suggest that this is something else.  Maybe a planetary nebula.  In any case, there is not reference to this, though the stars in the center do have references.  Second, the feature on the right side of the image looks and awful lot like a planetary nebula.  Again, no reference to this through any of the databases.  One may guess an irregular blue galaxy.  But this area is not very transparent to extragalactic objects.  I found one galaxy by eye and it is not very easy to see.  In addition, this object appears to be in line of sight with obvious molecular cloud.  I suspect that it is a planetary nebula.  My image is devoid of a stellar object in the center of the feature.  Checking my original unstretched stack and mosaic confirms this feature and likely was removed in my star reductions.  The PanSTARRS DSS2 image is as follows: 
I find two references to the central stellar object regarding radio emissions.  The only image I see radio spot there is from the VLA.  Its not particularly outstanding and in a field of many such scattered signals.  Perhaps it is an active galactic nucleus.  If so, this is a very lucky shot through a hole in the dense cloud here.  Third, is the reflection components generated by the close proximity of mu CEP to dust shown in the center of the mouseover.  In retrospect, I can see this in my earlier versions.  But this RN becomes very much more obvious in my current offering.  Also, it is clear that mu CEP actually imparts at least partial illumination to a pretty extensive area, based on color differences with the excited hydrogen that is the result of the UV dominant stars in the central cluster.  Finally, I am happy with a good number of other revealed dark and light structures that stand out in this star-reduced version.  I am also happy that I can actually see the listed planetary nebulae.  Often I see them marked, but with nothing to back it up!

I struggled with whether to post this or not.  I worry that it may be too over the top.  Not really my style!  And I am not happy that some of the darkest areas are flat black.  Oh, well!  I went into this revision to try to improve the stars and maybe detail using the newer tools available.  Knowing full-well that such is folly when working with a 6 panel mosaic and a wide field telescope.  Small improvements along those lines would likely only be noticable when deeply pixel peeping.  In the end, I produced what I feel like is a bit of an outrageous stretch for a final product.  Yes, the noise is much improved.  But because of circumstances, I reduced the stars a lot more than my original, so other than cleaning up some halos, no real star work, other than than for aesthetics.  Though I have to say that the newer star reduction methods made the job very much easier.  The reason for the more extreme star reduction was that I wanted to highlight more of the fainter image regions of the main nebula body and the surroundings, the surroundings being the reason I did a 6 panel mosaic in the first place.  In doing so, I wanted to highlight the faint colors of those molecular clouds.  Show the light browns and some darker browns.  In the end, what drove me to this presentation is: 1. I kept seeing more stuff more clearly that the original image only alluded too.  2.  I kept seeing more discrimination in coloration that pointed to interesting illumination, with the an example of mu CEP and its surrounding reflection components.  This is not something I really noticed in AstroBin images, with the bulk being narrow band images.  There are very few if any OSC, or LRGB images of the field I present here with any sort of resolution that allows closer inspection.  Here I have resampled this to keep the size under 50 MB.  Narrow band images of the field are very nice, but they can't capture the reflection components which turn out are prevalent throughout.  In addition to specific reflection components, the whole field, outside the confines of the Elephant Trunk Bubble seem to have a haze.  I believe this is real.  It is intervening dust to our line of sight that affects our view of this area.  On the other hand, the clearing effect of the UV pressure from the central bright cluster stars has opened up a less obstructed view of the most beautiful parts of this nebula.  Hence its popularity!

In addition to leaving the original versions on this page, I replaced the Starless version with an update to this latest revision.


Original Description:
This is my first attempt at doing anything more than a 2 panel mosaic.  I was happy with my last Elephant Trunk project regarding color, contrast and framing even though there was some ugly stuff at the finer details.  It actually printed up nicely at 8.5 x 10.5 on metal.  But I thought that I might like an image of the full nebula including a bit of the surroundings for context.  This required 6 panels.  It also allowed me to adopt the use of more sophisticated acquisition and processing skills and was a test of my computer's capabilities.  Being a rather new user of NINA, this forced me to fully implement the multi-panel framing process, setting up the more complex sequence, and fully employing the use of plate solving to automatically move to each position without my needing to be awake, including meridian flips.  This mostly worked.  So 6 panels, 15% overlap, minimum of 3 hours for each panel, took 8 days to get it done with these short nights.  I knew ahead of time that there were some bright stars to deal with and the nebula itself is not blazing, but pretty bright in spots, so I went with Mode 3, gain 0, offset 8, 240 sec exposures. Very very deep well and I never saturated a pixel the whole time, even with my RASA!   Conditions were generally good (west winds keeping the smoke heading east).  Of note, and quite unable to explain, is that I got round stars from corner to corner.  First time ever with the telescope and camera.  Not sure what I did to earn that, but I did not fool with it for 8 days!  (There are the limited regions of oblong stars in this image, but that is due to the "high precision warping" that the stitching algorithms uses.

For processing, I did what I learned online via typical sources, including PixInsight team.  I have heard that PI is not the easiest for doing mosaics, but I was not about to download still a different software package and relearn something new just yet.  In any case, a cursory mention of PIs Mosaic by Coordinates by one online source was enough for me to take that route and to give it a try and it worked beautifully!  I won't go into the details here, but it was a fast way to generate the 6 panel template.  Other than the cropping of the usual crap from the margins of the stacked panels, no need to crop to uniform size.  dnalinearfit was used to get consistent intensity for all panels.

The mosaic was huge.  I processed at full resolution (yes I did dither!).  Things were a bit slower than usual with the computer.  Most of the big computing tasks were done on an extracted luminance panel, so that speeded things up considerably.  Mostly, the job consumed a huge amount of disk space.  I'll have a lot of cleaning up to do.  But I can't get rid of much, because while I am presenting this today, there is much that leaves me unsatisfied and I will be working on this over time.  But I can't say I am unhappy either!  I loaded a "final" image, which is a resized (1/2 resolution) that is 25MB.  It looks pixelated to me for some of the details I like to see, so the revision is the full jpg.  Be warned if you look at it at full size.

While processing, I had lots of time to explore this region with Aladin.  In particular, looking at all the YSO and such in the elephant's head.  Many become visible right around 1 um.  So this is an area that I will be exploring with the NIR setup I coddled together and with the new telescope I want, just as soon as manufacturers start making telescopes again!  Not much more to say about this region.  It is not atypical for such emission nebulae of this sort, with many dark molecular clouds, large and diffuse, dense and opaque, and tight small knots scattered about in front of the emitting nebulosity.  While not super dramatic, one can see some detail in the scattered molecular clouds surrounding the main nebula.  Some of these are dark, but some have some weak emission.  I have an Ha filter on order, and when manufacturers start selling them again, I will try to put that to use.  There are a couple of pretty, and pretty small planetary nebulae visible.  And plate solving in PI shows another one or two that do not show up at all.

While I do astrometric color calibration and try not to mess with the color balance, I plead guilty to enhancing color saturation to my own taste.  This may not be the most dramatic presentation of this nebula, but my intent was to preserve as much of the finer detail as I could using a OSC camera.  In fact, when I do make a metal print of this, I will likely boost the saturation.  The detail that I have here will not show on a print that is measured in inches.  I do not use a star removal/replacement process but I do like to reduce star intensity and size to make it easier to see the nebula details.  However, I will also soon add a starless revision and also intend to include a revision that will have just a little star removal/reduction and minimal color saturation enhancement.  I think it is interesting to see what the true starfield looks like relative to the nebulosity.