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Entire Moon, April 13, 2019, good details, C9.25 Edge HD

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#1 Tom Glenn

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Posted 20 April 2019 - 01:07 AM

Last weekend had a lot of potential for lunar imaging for us folks in the Northern Hemisphere, with the near First Quarter Moon being at very favorable declinations (over 70 degrees altitude for me).  On top of that, I had a clear forecast for the weekend, and the waxing gibbous Moon crosses the meridian at a very convenient time in the evening, which doesn't require any heroic efforts to get up early or stay up late.  Unfortunately, the final piece of the puzzle, and the most important, the SEEING, was not appearing to cooperate.  The various seeing forecasts ranged from bad to horrible (2" on Meteoblue, and "poor" to "average" on CDS.....not a good sign!!), but I couldn't understand why given the weather patterns in my area, so I decided to tempt fate and image anyway.  Luckily, the seeing was better than forecasted on the evening of April 13 (April 14 UTC), although still not the type of seeing we hope for.  I would rate it as a solid "4" on the Pickering scale, as observed during collimation on star with my 9.25 inch telescope, with moments of a "5".  As has been discussed in other threads, those values, despite being categorized as "poor" to "fair" (depending on the aperture), will actually allow fairly decent imaging.  I also imaged on the night of April 12 and April 14, but the 13th appeared to be the best seeing, so I started processing that evening's data first.  

 

Here is the result of a four panel mosaic using my C9.25 Edge HD and ASI183mm camera with a green bandpass filter.  You will need to download the full size image from Flickr to see the full resolution, but I will also post some cropped panels of a few select areas below for viewing in the forum.  Highlights of this lunar phase include Copernicus located directly on the terminator at sunrise, as well as a number of other popular features near the terminator.  Click for full sized images.  

 

Moon_041319_TG.jpg


Edited by Tom Glenn, 20 April 2019 - 01:08 AM.

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#2 Tom Glenn

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Posted 20 April 2019 - 01:08 AM

Plato_041319_TG.jpg


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#3 Tom Glenn

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Posted 20 April 2019 - 01:09 AM

Hadley_041319_TG.jpg


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#4 Tom Glenn

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Posted 20 April 2019 - 01:09 AM

Copernicus_041319_TG.jpg


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#5 Tom Glenn

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Posted 20 April 2019 - 01:10 AM

Hyginus_041319_TG.jpg


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#6 Tom Glenn

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Posted 20 April 2019 - 01:10 AM

Ptolemaeus_041319_TG.jpg


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#7 Tom Glenn

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Posted 20 April 2019 - 01:11 AM

RupesRecta_041319_TG.jpg


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#8 Tom Glenn

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Posted 20 April 2019 - 01:11 AM

Tycho_041319_TG.jpg


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#9 Tom Glenn

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Posted 20 April 2019 - 01:12 AM

Moretus_041319_TG.jpg


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#10 Tom Glenn

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Posted 20 April 2019 - 01:16 AM

That's it for now.  When I get around to processing the data from the other nights last weekend I may post if they pass muster, although it took me awhile to get this data together, so that probably won't happen anytime soon, and the seeing didn't look as good those nights anyways.  


Edited by Tom Glenn, 20 April 2019 - 01:16 AM.


#11 scadvice

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Posted 20 April 2019 - 01:22 AM

Very nice detail!



#12 gfstallin

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Posted 20 April 2019 - 03:19 AM

Meh, these are just okay. lol.gif

 

Obvious joking aside, I love Plato with Vallis Alpes - excellent detail in both in a wide-field image. bow.gif  Hyginus is great as well. I've focused on Hyginus before, but seeing it in your wider context makes it much more obvious it is different from other lunar craters. I've been meaning to get around to completing a mosaic as well. Work and weather here in the Mid-Atlantic tend to get in the way. I might have to take a day off the next time lunar phase and seeing are both advantageous. This weather pattern cannot last forever. 

 

George



#13 Asbytec

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Posted 20 April 2019 - 03:23 AM

I N C R E D I B L E !



#14 Wouter D'hoye

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Posted 20 April 2019 - 03:47 AM

Great set of images, Tom. 

 

Thanks for sharing.



#15 kevinbreen

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Posted 20 April 2019 - 04:28 AM

AWESOME images Tom!
I love them all especially Rima Hadley.

#16 aeroman4907

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Posted 20 April 2019 - 10:32 AM

Those are excellent results Tom!  Even with the seeing at a Pickering of 4 to 5, do you feel that the various level winds were pretty unidirectional?  Was your relative quality scale fairly uniform and were you able to stack a good percentage of images?  I am sure the 70 degree declination helped!

 

I don't image with filters, so I casually read about their use, but if I remember correctly your use of a green filter must also indicate some fairly decent seeing.

 

Weather here has been terrible for imaging, so no joy for this lunar cycle...



#17 james7ca

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Posted 20 April 2019 - 12:42 PM

Tom, looks good. You covered just about all of the really interesting areas with your crops. This lunar phase and the following day probably have more more opportunities for good images than any other time on the moon. The last quarter moon and the waning gibbous really don't have anything to compare (in number).

 

I was out on the same night but with my Celestron 102GT (4" refractor) trying out a Baader Solar Continuum filter. That filter has only a 10nm bandpass which I decided later was just too strong on such a small scope (and the 1.25" filter itself cost more than the scope, although I really purchased the filter for solar work and optical testing). It worked okay for a full-disk montage with the ASI178MM but I had to reduce the reproduction scale to get a sharp looking image.

 

[UPDATE]

I've posted the image that I took using the 102GT, almost exactly the same time and phase as was done in Tom's shot (for comparison).

 

  https://www.cloudyni...27#entry9309807

[/UPDATE]


Edited by james7ca, 21 April 2019 - 04:00 AM.


#18 DesertRat

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Posted 20 April 2019 - 01:35 PM

Tom,

Once in a long while an image shows up here that truly astounds, and this is one of them.  Celestron could not issue a better advertisement for an EdgeHD 9.25.  Sharp from corner to corner, what more is there to like? waytogo.gif waytogo.gif waytogo.gif waytogo.gif waytogo.gif

 

Not to take anything away from the imager, you did a great job in the processing, at just the right point to preserve both tonality and details.  One can scan your image in full and discover stuff they didn't know was there!

 

If you get better seeing, you'll scare us! shocked.gif

 

Glenn


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#19 Kokatha man

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Posted 20 April 2019 - 06:52 PM

Yep - I agree entirely with Glenn's assessment above Tom...& his rating of waytogo.gif waytogo.gifwaytogo.gif waytogo.gif waytogo.gif ..! 

 

Might even tempt me to look a bit more at that bright thingy in the sky perhaps... :lol:



#20 Tom Glenn

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Posted 20 April 2019 - 11:26 PM

Many thanks to scadvice, George, Norme, Wouter, Kevin, Steve, James, Glenn, and Darryl for all the nice comments.  They are certainly much appreciated.  I realized that until last weekend, I hadn't even set up my C9.25 scope since before Christmas!  A mix of poor weather (at least by San Diego standards!), clouds, fog, rain, and bad seeing even when clear have been responsible for this.  It was good to get it back out.  I haven't been in any rush to attempt planets yet, since last year I really didn't get anything worthwhile on Jupiter until May, with optimal results occurring in June and July for both Jupiter and Saturn.  The problem with early morning imaging is that I often get overcast skies that roll in around 4am, so I'm just playing the waiting game with Jupiter and Saturn for a bit.  The waxing gibbous Moon near First Quarter is optimally placed right now for me, although I missed it last month due to clouds and horrendous seeing.  This month was a bit better.

 

I will respond to a few specific comments and questions below:

 

 

Hyginus is great as well. I've focused on Hyginus before, but seeing it in your wider context makes it much more obvious it is different from other lunar craters. 

Indeed, George.  Hyginus is different in that it was not caused by an impact event, but is rather thought to be volcanic in origin.  

 

 

Those are excellent results Tom!  Even with the seeing at a Pickering of 4 to 5, do you feel that the various level winds were pretty unidirectional?  Was your relative quality scale fairly uniform and were you able to stack a good percentage of images?  I am sure the 70 degree declination helped!

 

I don't image with filters, so I casually read about their use, but if I remember correctly your use of a green filter must also indicate some fairly decent seeing.

 

Steve, I can't say much about the winds, other than there was a fairly significant jet stream but it was moving within 90 degrees of the same direction as surface winds.  Mostly this outcome was just a luck of the draw thing.  I imaged on Friday, Saturday, and Sunday nights last week, and Saturday had the best seeing of the three.  The moments of "5" on the Pickering scale (for whatever that's worth) improved the outcome, whereas the other nights looked more like a steady "4".  Still not bad, but the scale is fairly arbitrary, not linear, and the aperture used to gauge the scale definitely affects the quality of the outcome.  Very decent imaging can be done at a "4" with larger scopes (despite being listed as "poor"), and very excellent images can be obtained at level "5", despite this being listed as "fair".  I've only occasionally encountered something that I would call a level "6" or "7" with my 9.25 inch scope.  But once you get to levels "3" and below, that starts to turn into the garbage zone for the Moon, especially with wide field imaging on the ASI183 where you can't run fast frame rates.

 

I took a screen grab from AS!3 after processing a few of my files.  Here's an example below.  As you can see, the seeing was very consistent.  This graph doesn't mean "good", but simply consistent.  Although it turns out that really terrible seeing is usually also chaotic, and so you don't get a graph like this unless things are at least decent.  The other takeaway here is that if you add up all the times, you see that this file took 4 hours to process in AS!3.

 

AS3_screengrab.jpg

 

For the two panels spanning the terminator, I collected 4000 frames and stacked 1000.  For the two panels covering the limb, I only collected 1000 frames (due to file size space limitations) and used a 500 frame stack in the final result.  I've found that when imaging the Moon, you can get very nice results stacking as few as 100-250 frames on the sunlit portion of the Moon, but the advantage of stacking more frames comes in the form of SNR improvements in the shadowed regions along the terminator.  Extra frames stacked don't necessarily help improve resolution or detail, but do allow you to increase the exposure in post without introducing as much noise along the terminator, which serves to increase the amount of perceptible detail.  For the more evenly illuminated portions of the Moon, you can get away with fewer frames collected and stacked.  If a stack of 250 frames (assuming exposure settings were good) doesn't yield good detail on an evenly illuminated portion of the Moon, then the seeing wasn't good enough to make it worthwhile.  

 

With regards to the filter, green is usually associated with good seeing, but my Baader green filter has become my standard filter.  I tend to use this by default now.  I feel like the restricted bandpass helps resolution, even if seeing is only "fair", whereas a long pass filter allows many more wavelengths to pass though, potentially reducing resolution.  In general, if conditions don't look like they are worth using the green filter, then I won't even image with the C9.25 and I'll just use my 6 inch Newtonian.  Although even here, with the smaller aperture, I still would be inclined to use the green filter. The difference in results in likely marginal though.  For an interesting comparison, take a look back at this post I made over a year ago in March 2018 using the 610nm pass filter.

 

https://www.cloudyni...-edge-asi183mm/

 

That lunar phase is almost identical to the one in this post, varying by less than 2 degrees of longitude of the terminator, which amounts to less than the width of Copernicus, as you can see by comparing the images.  The detail in these images is nearly identical, and in fact any differences are probably within the normal variation of processing.  However, I feel like there may be slightly more fine detail in my more recent image (resolution, not contrast....my image from last year has slightly more contrast in some regions, due to processing variations), although you really have to pixel peep, and even then, it's arguable.  I seem to recall the seeing from last year's image with the 610nm was better than the seeing I had last weekend, but that's also hard to say definitively.  Basically, both filters produce very nice images. 

 

 

This lunar phase and the following day probably have more more opportunities for good images than any other time on the moon. The last quarter moon and the waning gibbous really don't have anything to compare (in number).

 

James, I agree this is a great phase to image, with many of the most popular features visible.  I also like the waning gibbous Moon at about 1-2 days before Last Quarter, but in that case the window is closing on many of the popular targets, whereas in this case the window is just opening.  Also, waning gibbous Moons require more dedication, as often the best time to image is 4am.  The other thing I like about the waxing gibbous Moon just after First Quarter is that you get several days worth of good imaging near the poles, since the terminator moves less in absolute distance the farther you get from the lunar equator.  Whereas you may only have one day of optimal lighting on Ptolemaeus, you usually get several good days on Clavius to the south, and Plato to the north.  

 

 

Tom,

Once in a long while an image shows up here that truly astounds, and this is one of them.  Celestron could not issue a better advertisement for an EdgeHD 9.25.  

Thanks for the kind words, Glenn.  If Celestron wants to help me fund an upgrade to a C14 Edge, I would be happy to provide them with some promotional material!  In all seriousness though, I have been very happy with the C9.25 Edge.  On a dozen or so occasions per year, I am able to push the limits of this scope, and it really does perform quite excellently.  In better seeing, I often play around with 1.5x drizzle versions of lunar images with my ASI183mm, and I also have a Siebert 1.3x barlow to fully maximize the potential of the 2.4um pixels, but to be honest, all of those variations are just tiny (almost imperceptible) improvements over the images at f/10, such as the one posted here.  To really achieve a meaningful improvement in resolution, I would need to increase my aperture.  I have often said in other posts that most people vastly underestimate the resolution potential of their scopes, due to a combination of seeing limitations, coupled with user-controlled aspects such as collimation, thermal equilibrium, focus, capture and processing parameters.  But on the Moon in particular, the C9.25 Edge is a tremendous performer.  An image such as this one only requires four panels to cover the entire Moon, and the less panels you have to capture, the better.  

 

 

Yep - I agree entirely with Glenn's assessment above Tom...& his rating of waytogo.gif waytogo.gifwaytogo.gif waytogo.gif waytogo.gif ..! 

 

Might even tempt me to look a bit more at that bright thingy in the sky perhaps... lol.gif

Thanks Darryl.  The five thumbs up rating is certainly appreciated, and I would definitely enjoy seeing a lunar image or two from you!  I know you posted one a few weeks back in another thread.  If you ever had an entire post dedicated to lunar images, I think some people around here would be stunned!  


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#21 Arctic eye

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Posted 21 April 2019 - 04:47 AM

Excellent capturing and processing! Too often lunar images tend to look more like drawings instead of photos, but these are truly beautiful in all aspects. 



#22 Ed D

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Posted 21 April 2019 - 08:44 AM

My finger got tired from clicking so many likes!  Seriously, your lunar images are all great.  waytogo.gif bow.gif

 

Ed D



#23 DesertRat

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Posted 21 April 2019 - 02:50 PM

Tom,

 

I calculate that for your scope and camera a field at the sensor of approx 19x13 arc-minutes at f/10.  If that is not correct please advise.

 

My question is this: do you crop out anything other than the inevitable corner stacking anomalies?  That is - do you see anything suggesting poorer correction at the limits of your frame?  I suspect not much if any, but am curious as to your experience.

 

As far as seeing estimates go I have essentially ruled out the possibility of perfect seeing as it does not exist except for the briefest of moments for larger apertures such as yours.  Estimates with more than 4 or 5 levels are difficult, and human perceptions of something so dynamic, complex and rapid preclude more quantization.  A simpler system has more value in my view with possibly 3 or 4  levels.  And then there is a fourth or fifth, Darryl's "diabolical" rating, where one may take data for testing purposes, or simply wait it out with hope, or just start gathering up things for the night.

 

By the way your descriptions above are valuable contributions to anyone wanting to perform this kind of imaging.  Good work!

 

Glenn



#24 airscottdenning

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Posted 21 April 2019 - 06:49 PM

Just stunning -- thanks!



#25 Tom Glenn

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Posted 22 April 2019 - 01:05 AM

Tom,

 

I calculate that for your scope and camera a field at the sensor of approx 19x13 arc-minutes at f/10.  If that is not correct please advise.

 

My question is this: do you crop out anything other than the inevitable corner stacking anomalies?  That is - do you see anything suggesting poorer correction at the limits of your frame?  I suspect not much if any, but am curious as to your experience.

 

Hi Glenn, 

 

Your calculations are correct regarding the angular dimensions of the frame.  The sharpness to the edge is extremely good.  There is of course the small band of stacking errors, and I notice some blurring of the image just a bit inside this band, which I think is still related to stacking difficulties near the edge.  But otherwise, I see nothing to indicate any deterioration of the image towards the edge of the frame.  With frames as large as this, there are some regions that appear sharper than others even within a single stack, but the variation is random, and not associated with closeness to the frame boundary.  One difficulty with composing high resolution images with such large frames is that the frame rate is very low (no faster than 19 fps for the full frame), and so there is much less room to maneuver to "beat the seeing".  File size limitations also preclude capturing enormous files, so there's no way to simply capture 10,000 frames and stack the best 1000, which is what I used to do with my ASI224, and many others do with smaller frame cameras on the Moon.  The file sizes here accumulate at a rate of 20GB per 1000 frames in 8-bit (and 40GB per 1000 frames in 16-bit!).

 

The number of frames to stack on the Moon is actually quite an interesting discussion, and depends on a variety of factors.  Here I captured 4000 frames for the panels covering the terminator, and stacked 1000 of these in the final image.  The capture was with 8 bit data.  This in itself is an entire discussion, and I have lots of thoughts on the matter, but I'll try to keep it brief.  Basically, 16 bit data is almost always better for the lunar terminator when using a large sensor that spans a huge dynamic range.  This is because you have to stretch the histogram pretty heavily to bring out details along the terminator in an image that was exposed so as not to clip the highlights.  However, 16 bit files have slower frame rates and double the file size, and so I can't capture as many frames.  This means that if seeing is less than ideal, I like my results better capturing more frames in 8 bits and then being more selective.  For example, in this case I collected 4000 frames and stacked 1000, but if I had captured in 16 bits I would have only collected 2000 frames to achieve the same file size.  So there are logistical considerations.  If seeing is truly excellent, you can easily get away with 2000 frames, and with good data you can stack as few as 250 or so frames and get an excellent result (even 100 frames can be OK, but along the terminator, I really like to stack at least 500-1000 to be honest).  When I stack 1000 frames of 8 bit data, the result is almost as good along the terminator as if I had captured in 16 bits (and indeed, stacking frames does increase bit depth, so the 8-bit capture actually has far more than 8 bits of data in the final stack).  And note that I'm only talking about quantization error/noise along the terminator......the bit depth has no effect on the details or resolution elsewhere in the image.  So the bottom line is that in a perfect world I would always capture in 16 bits on these lunar images, because I have noticed a benefit with regard to noise in the shadows, but due to practical considerations in less than perfect seeing, I actually like the results I get with 8 bits better because I can collect more frames, which helps with the seeing.  Also worth noting is that the panels that spanned the illuminated limb of the Moon represent a stack of 500 out of 1000 frames.  I collected less frames here due to file size issues and hard drive space, and I have noted on numerous occasions that I simply don't need as many frames for these regions of the Moon.  The primary advantage of more frames is noise reduction and less quantization error when stretching the histogram, which only really applies to the terminator and not the limb.  

 

I also thought some people might be interested to see a quick summary of what I do to get the final image in Photoshop.  This is super abbreviated, but may be of interest.  I have commented before about how woefully inadequate panorama software is for making lunar mosaics.  Most fail to align with enough accuracy for me, and even if they do align well (like Microsoft ICE), they don't give enough flexibility with the blending, and ICE in particular clips to black, which can absolutely destroy terminator detail.  So I manually align the panels in Photoshop, which is really only feasible with a small number of panels.  The raw panels look like this:

 

raw_mosaic.jpg

 

Notice the different exposures.  Each panel was exposed to about an 80% histogram (to leave room for deconvolution without clipping), although the versions presented here have already undergone deconvolution.  The darker panels have histograms that are dominated by a few very bright spots.  To avoid clipping those to white, the overall exposure looks low, but this is a good thing, and is why we need to stack a lot of frames because there will be significant adjustments to this image.  The camera simply does not have the ability to reproduce what the human eye perceives without some significant editing.  The first thing I do is perform an overall gamma stretch just to make things easier to see for blending.  This results in the following:

 

raw_mosaic_gamma.jpg

 

Now I blend the panels together.  I make individual Levels layers in Photoshop for the darker panels, and perform a slight gamma adjustment isolated to each layer to match the exposures.  I then manually draw layer masks along the boundaries of the frames with a feathered brush to blend the result.  This intermediate image is presented below, along with its histogram.  Note the spike on the right does not correspond to any points in the image, but to the white borders.  

 

raw_mosaic_blended.jpg

 

histogram_intermediate.jpg

 

This actually starts to look reasonable, and forms the base image for all of the final edits.  At this point, there are a number of directions someone could take, and much of it is personal preference.  I have stated many times before in other posts, that if the goal is a realistic representation of the Moon, then the lunar surface leading up to the terminator cannot be left overly dark.  If you look at the Moon by eye, or using the NASA simulator, you will see that the Moon displays fairly high levels of illumination until you approach very near to the terminator.  The Moon does have a fairly low albedo,  but it is not as "dim" as many think.  Much of the highland regions are similar to weathered asphalt or concrete in reflectivity, whereas the maria are closer to fresher asphalt, but they are illuminated in direct sunlight, and so should not appear overly dim, until you get to the region in which the Sun is partially below the lunar horizon.  In many images, the maria along the terminator in particular are overly shadowed and devoid of detail, whereas by eye you can easily perceive the detail.  The main problem with reproducing this in images is that when you raise the exposure in post, you encounter noise issues.  This is where the capture parameters and processing experience come into play, but sometimes you are simply limited in what you can do.  I make my final edits attempting to blend my personal preferences for details with a somewhat natural look, although opinions will of course vary in these matters.  For example, I'm fully aware that the most realistic interpretation of the Moon would be more bland than my final version presented here, as the Moon tends to look pretty washed out by eye (probably closer to my penultimate image above).  So this is simply my interpretation this time around, and I often change my preferences as I go along!  The final image and histogram are below.  One will also note that the black point has been shifted off the left edge.  This is a personal preference, as I feel there is more perceptible detail along the edge of the terminator if black clipping does not occur, and if true black is slightly gray.  One final note is that the histograms shown here are based on the 16-bit Photoshop file, but once things get saved as jpegs the black levels and the entire histogram change to small degrees.  

 

mosaic_final.jpg

 

histogram_final.jpg


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