This was an unadvised field of view to tackle with my 61mm, f5.9 optic.  As far as some of the better galaxy clusters to be had, this one is well within a fairly dense field of stars.  So using a small aperature telescope, which is one way to get nice big fat stars, really detracts from the primary subjects of the field.  Not only that, but such a wide field is meant to highlight the larger features and details of whatever the target objects are.  A field such as this is not the strength of a 61mm telescope.  So this became an unexpected addition to my "Intergalactic Travelers' "  group, which I guess must be a series for me, since this is now the third such image!  The reasons this is in The Series is precisely the reasons above (and also see below).  Please look at the Earth View (rev B) of the same field to see how the stars impact a 61mm image of this field and please consider that image was very heavily star-reduced!  The mosaic, in Revision C is not star reduced.

The project turned into a learning experience for me in multiple ways.  After seeing the unprocessed stack, I noticed that NGC891 was one of the few prominent galaxies.  I also noticed that it was poorly resolved, though that aspect is not really noticed when viewed full-field.  But I just couldn't ignore the fact that I had a bunch of hours of data of a much narrower field of view taken from my 12 inch, f4 Newtonian, using my asi071 camera.  I never posted that image because the conditions were horrible and the stars were bloated and disfigured.  However, I have always been impressed with the fact that I could get a lot of nice (and real!) detail out of the galaxy's cloud stacks, even still.  So I decided that I would bring that field of view into this image and marry them.  No idea how to do that, but it needed to happen.  (In fact I am not sure I can even remember how I did it.)  Challenge: Bring data together from two hugely different image scales (61mm, f5.9 and 305mm, f4), two different pixel sizes, two different orientations, two completely different exposures.  Challenge: Do so with the result being noticably better.  That is even if the better resolution cannot really be seen when viewed at full field, at least I would not have made the image worst!  No real reason to do this for this image, but lessons learned could be put into use for future projects.  I won't go into any detail as to how I did this, unless someone shows interest and asks.  I can say that dithering both acquisitions and doing 2X drizzle helps.  This yeilded an arc-sec/pixel scale for my z61 image that helped accept at least some of the extra resolution of my larger aperture scope's image.  The PixInsight functions I used to do the merge really had to crank (over an hour of full-on processor activity) to yield the two registered images to make this work.  See in the third Revision to give you a better idea of how the melded images looked at the end of the process and the two different scales of the image fields.  I did not use any of the gradient tools in PI to merge the registered images.  They did a horrible job and were completely unnecessary.

Begin rant: Other reasons than those that I stated above for choosing to do an intergalactic (starless) view of this field came about because of my increasing critique of the defects that come about through the use of SXT and BXT.  Yes, this may be partly due to my being overly picky.  But the more I have been working with these, in particular with these galaxy images, the more I find SXT and BXT to not be lossless transactions.  Since I like those background tiny galaxies, I just can't simply let them die by using a heavy hand.  In this case, I found that SXT actually removed not just the smaller smudges, but also some whole NGC class galaxies from this image!  And to those who don't care, I warn you that when you apply SXT and BXT, these can also remove certain details from within emission nebulae.  When and why this is so is not always clear, making it harder to control for.  I believe that if you were to do a simple SXT operation of removing stars from an image, then simply adding the stars back to the image, the structures are faithfully reconstructed.  However, that is not normally why star removal is done.  Typically, stars are removed to then enact an operation on the starless image, only after which the stars are recombined.  This is where damage can occur.  Example, my favorite star reduction methods are Bill Blanshan's methods.  I find them to be far more faithful, gentle, and linear than to the BXT star reduction/halo reduction methods, which if done to a stronger effect seem to squeeze the stars and can create spikes and other artifacts.  But the Blanshan methods require a good star removal, and if galaxies, or parts of galaxies are extracted with the stars, then the Blanshan methods will reduce the galaxies, parts of galaxies and any other parts of nebulae along with the stars.  End of rant.  (FYI, I still love SXT and BXT.  Especially, BXT deconv.)

In any case, please do pixel peep NGC891 to see if I succeeded.  Understand that I could not achieve bringing all the detail that I had of NGC891 into this image since it would have required that I increase the size of the file at least 3X more than it is.  But I can assure you that it is better than what the 61mm scope could do.  In any case, the point of such a starless view is to imagine that if you were well away from the confines of the Milky Way galaxy, where no stars were within your field of view, then maybe this is what looking in this direction might look like.