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Tonight I mostly just looked at the thing.

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#1 Borodog

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Posted 19 January 2021 - 11:02 PM

At about 5 tonight I drug the C8 out to set up for the evening without any real imaging plan. I roughed in the polar alignment and set about aligning my electronic finder with the main scope. After that I mostly just looked at the Moon via, gasp, actual eyepieces. First, I started with a big 2" 40mm that easily fits the full disk. Later I switched to the new 1.25" 24-8mm zoom eyepiece.

 

The Moon. It. Is. Amazing. I realized several things tonight.

 

1) No photograph I have ever seen of it does it justice. Sorry guys. It just seems impossible for the camera to capture what our eyes can see. Namely that it is bright white yet not blown out anywhere. It is brilliantly bright all the way to the terminator in a way that my photographs do not show. Somehow the camera captures what it is, a dirty dingy thing the color of ashphault, but not what we see, which is a brilliant white beautiful thing.

 

2) I can *see* the colors. Since I've been doing color treatments of the Moon by pushing the saturation I've realized that the different shades of browns and grays are there in the unsaturated image all along, plain as day if you know what you are looking at. Well it's just as true if not more so when actually looking at the thing. The subtleties of the colors and textures are downright sublime and plain as the nose on your face.

 

3) I believe tonight's phase must be my absolute favorite. The craters and mountains and rilles and maria near the terminator tonight were amazing. There was one particular large crater on the [southern] terminator completely in darkness except for the illuminated central peak. Just incredible.

 

4) As bright as the illuminated side is, you can see the dark side of the Moon by Earthshine right in the eyepiece; you can see the whole disk, at least for now. That gave me the idea to do something I've never done before: I observed the dark side of the Moon (it's all dark, really) by telescope. I moved the illuminated side out of the field of view and just let my eye get more and more dark adapted. As the minutes went by I could clearly make out features on the dark side of the Moon, both bright and dark. First was dark Grimaldi, which is easily recognizable as a very dark circle near the limb. Then was the extremely bright Aristarchus. Eventually I could see the large regions of light and dark; I found it helped to traverse up and down in my fine altitude adjustment, as the motion makes clear what is actually there and not sure a trick of the very dim light. 

 

5) The zoom eyepiece is a joy to use on the Moon, although I suspect it will be even better in my 10", which has a 1200mm focal length instead of 2000mm, which is the focal length of the C8. The full disk would not fit at 24mm in the C8, but it certainly will in the Dob. In any event, it was a pleasure to scan around the Moon and then zoom in by a factor of 3 for a close look. And it gives your eye a break from the brightness (I was not using a Moon filter tonight). If you don't have one yet, I highly recommend getting one just for observing the Moon.

 

6) At least for a while, I am going to be trying to recreate what I saw in the telescope tonight in my images. I don't exactly know how to do that yet. Stop pushing the saturation, for one. It doesn't need it. Two, compression. Our eye's can compress the dynamic range of an image in a way that the camera can't. So I have to figure out a way to do that, to achieve that brilliant white Moon with its sharp terminator that is somehow still not blown out. I don't even know if it's possible. But I'm going to try.

 

Tomorrow I'm setting up the Dob and the only thing I'm going to be doing is looking at the Moon.


Edited by Borodog, 20 January 2021 - 12:20 AM.

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#2 Stellar1

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Posted 19 January 2021 - 11:09 PM

Nice report, I find the same when it comes to lunar, no images ever come close to what I see with my eyes.


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#3 wrvond

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Posted 19 January 2021 - 11:10 PM

Astrospheric said it was going to be clear tonight so I had planned to take my C-8 out for lunar observing, too. Sadly, the clouds rolled in about 1730 and stayed. Maybe tomorrow night...


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#4 Borodog

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Posted 20 January 2021 - 12:23 AM

I took exactly one sequence tonight and I tried to process it to look like what I saw. So I turned the contrast down and the brightness up and hit the curves hard to try to keep the terminator sharp. This is as close as I could get. It's an abject failure. Doesn't even look like it came from the same object as what I saw.

 

 

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#5 Tom Glenn

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Posted 20 January 2021 - 01:13 AM

It is brilliantly bright all the way to the terminator in a way that my photographs do not show. 

Quite true.  Yes, the Moon is visually very bright, all the way to the terminator.  In most images, the terminator region is depicted as very dark gray, and depending on your monitor settings it may be hard to discern the details present in regions where it would be easy to see these visually.  Some of this is by processing mistakes (errors and lack of understanding of tonal distribution), but some of it is by design, because if you attempt to raise the levels of the terminator to more appropriate visual representations, two things happen: 1) artifacts tend to become more obvious, and 2) you run out of available dynamic range on the top end, creating an incredibly washed out look that isn't ideal either.  The camera has no problem capturing the details, but the human eye perceives it better than can be displayed on a monitor.  Although there are certainly details that can be extracted from the images that cannot be observed by eye, so each has its strengths.  



#6 Stellar1

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Posted 20 January 2021 - 01:51 AM

I took exactly one sequence tonight and I tried to process it to look like what I saw. So I turned the contrast down and the brightness up and hit the curves hard to try to keep the terminator sharp. This is as close as I could get. It's an abject failure. Doesn't even look like it came from the same object as what I saw.

You got the color temperature bang on.



#7 spkerer

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Posted 20 January 2021 - 09:02 AM

I completely understand what you're saying.  There are times I just get mesmerized observing the moon...  I often have plans of what I intend to observe, but sometimes they get cast aside as I lose myself watching the moon.  Watching sunrises and sunsets on there...  :)


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#8 Borodog

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Posted 20 January 2021 - 09:05 AM

I am wondering if film would exhibit the same natural compression as the eye? Analogous to tape saturation in audio recording. It sounds soooo gooood.

#9 aeroman4907

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Posted 20 January 2021 - 11:07 AM

Glad you enjoyed looking at the Moon visually.  I had a more limited experience, but yet still inspiring, recently when I viewed the crescent Moon with Earthshine and binoculars recently.

 

I am wondering if film would exhibit the same natural compression as the eye? Analogous to tape saturation in audio recording. It sounds soooo gooood.

Film likely would be even farther from the visual experience.  The DR of film is generally less than modern digital, so contrast differences will increase, not compress.  That doesn't even account for the benefits of stacking thousands of frames.

 

In truth, the limitations with imaging the Moon are also common in landscape photography.  The creation of the eye and brain to interpret what is seen is truly phenomenal.  The eye can relatively quickly adjust for brightness and focus.  The brain can quickly formulate an image and impressions (memories) of these images as we evaluate a scene we are observing, such as a beautiful sunset over a mountain range with wildflowers close by.  Our visual sense is compositing all over these visual impressions into one big mental 'image' in our brain.  Let's not even talk about how the sense of hearing, smell, and touch (sensation of atmosphere and temperature) affect what we "see".  For these reasons, local and global adjustments for brightness/contrast/image saturation are typically required with landscape photography.  Additional tricks such as focus stacking and HDR may also be required.  You are trying to convey in a single image that doesn't have the eye's benefit of changing "exposure" or "focus" to get an overall mental impression.  Even if you can get a digital file to look very similar to what could be seen by the eye, you then have limitations with the computer display or a print.  The computer display will be limited on field of view, dynamic range from light to dark, color display accuracy, etc.  A printed image will have even greater issues as proper lighting is required and reflections can be problematic.  So in that sense, seeing a beautiful landscape will always be more beautiful than any print or computer image can replicate.  The best you can do it try to replicate the 'feeling' of a scene with an excellent photograph.  The best compliments I ever receive on my landscape photography are when people say "Wow,, I really want to go there!", not when they say "That is a great photograph".  In the former compliment, it means the photograph has really begun to convey the beauty of the imagery when I first captured it.


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#10 Tom Glenn

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Posted 20 January 2021 - 03:48 PM

I am wondering if film would exhibit the same natural compression as the eye? Analogous to tape saturation in audio recording. It sounds soooo gooood.

From a technical standpoint, film is worse in every way to modern digital sensors.  The only reason to use film is that it does retain a "fun factor", but there are no advantages.  For Earthbound photography, the greatest advantage of digital imaging is that you can stack 1000+ frames.  This not only allows small details to be revealed, but adds tremendous dynamic range to the final image, which is important for the Moon.  Even at the level of individual frames, film offers no advantage over modern sensors, although there was a period of time in the early 2000s in which film continued to surpass digital.  But those days are long over.  

 

I have played around with some raw film scans from the Apollo era, some of which I have posted about.  The quality of the raw scans is variable, but the data is, in general, amazing.  

 

https://www.cloudyni...from-apollo-13/

 

One interesting property of film is that is behaves nonlinearly, whereas a digital sensor is linear.  It is difficult to completely blow out a film, but easy for a digital sensor.  This isn't an advantage anymore, however, because modern digital sensors have tremendous detail recovery at the bottom of the exposure, whereas film does not.  So with digital, you end up underexposing an image and then recovering shadows.  With film, you overexpose the image and then recover the highlights.  The end result is the same, and there is generally only about 10 stops of useful information contained in any individual image, whether digital or film.  But then when you stack 1000 of these digital images, you get much more.  

 

The main problem with lunar images is not anything technical with the camera or sensor (or film), but rather what Steve talks about above.  When you observe a scene visually, such as a landscape here on Earth, you are not observing a snapshot, but rather surveying the scene, constantly changing your focal point and direction of gaze.  The human eye can only appreciate about 10 stops of exposure with fixed gaze and pupil size, but because you are constantly changing your gaze, your histogram resets each time, so you can see much more than this.  Your brain then computes an impression of the image, but this is composed of observations and memories over the past several seconds to minutes.  So it's like real time HDR, and also in 3D (at least for images using both eyes).  There is simply no way to recreate that in a static image.  


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