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And you thought stacking 200 images was a big deal...

astrophotography
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#1 OldManSky

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Posted 20 February 2019 - 06:44 PM

...take a look at what putting together 50,000 images can do:

 

https://www.mnn.com/...-andrew-mcarthy


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#2 Boom

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Posted 20 February 2019 - 09:10 PM

This photo has been making the rounds...

 

But correct me if I'm wrong, as I'm not an astrophotographer, that 50,000 photo headline is sensational clickbait. bangbang.gif bangbang.gif   Don't guys here routinely stack multiple tiles of thousands of frames for a total of 20,000 to 30,000 frames for a "typical" lunar mosaic?  I even recall someone here saying that more frames isn't always better.  

 

I don't want to downplay the efforts of the photographer, as I find the image exceptionally artistic.  But for "50,000 images", the detail is incredibly LOW.   


Edited by Boom, 20 February 2019 - 09:11 PM.

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#3 t_image

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Posted 20 February 2019 - 09:52 PM

This photo has been making the rounds...

 

But correct me if I'm wrong, as I'm not an astrophotographer, that 50,000 photo headline is sensational clickbait. bangbang.gif bangbang.gif   Don't guys here routinely stack multiple tiles of thousands of frames for a total of 20,000 to 30,000 frames for a "typical" lunar mosaic?  I even recall someone here saying that more frames isn't always better.  

 

I don't want to downplay the efforts of the photographer, as I find the image exceptionally artistic.  But for "50,000 images", the detail is incredibly LOW.   

So yes, in Solar/Lunar/planetary imaging ("lucky") method involves taking short clips of video and stacking video frames (after selecting best frames that capture a 'more still' moment of the object seen through the bubbling atmosphere-overcoming "seeing issues"),

However the DSO AP method is to stack longer exposures in order to show fainter objects (like the background stars)...

The image is a composite of the two methods with different exposures as the article somewhat explains.

So equivocating on the word "images" between video frame numbers of lucky imaging with DSO AP subs needs to be avoided.

 

The "virtualization" situation that arises here is the many images were acquired over one hour. The Moon in one hour would have drifted through the frame of the background stars so that only 1/2 of the disk would still be in the frame.

So the image is a composite of the processed Moon over the processed star background where it would be at one moment over the hour long period.....

 

To compare to a more intuitively noticeable time distortion composite it would be like a composite photo of a someone's watch indicating a certain time while in the background is a motion streak of an individual (maybe headlamp at night) running over a long course that would have taken a long time to elapse.

However the image (Moon+stars) itself doesn't betray a time distortion since it possibly could be a singular image taken from a very advanced future tech camera with a sensor with amazingly high dynamic range capacity and microshutters to allow the faint stars captured near the disk of the bright lunar surface.....

 

The HDR composite isn't bad considering the small dynamic range ceiling all typical displays limit the visible scene to,

however I wish the image conveyed that the sky background was darker that the Mare on the Earthshine part of the Lunar surface.

But such would probably require a HDR file with a pro HDR display to appreciate such.....

 

As to detail,

it does more authentically represent what one sees in that the Lunar terminator is the best part of the Moon to observer surface detail as the bright parts and the Earthshine parts when visually observing don't betray the finest details compared with the terminator (washing out effect-the reason).

In comparison, processed images of the Moon (especially fully lit) usually show the Lunar surface with more detail than one visibly sees across the entire surface because of the lighting--i.e. to some "over-processed."

Note the compositor's intention was to simulate what he saw, not to capture every detail...


Edited by t_image, 20 February 2019 - 09:54 PM.

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#4 Boom

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Posted 20 February 2019 - 10:13 PM

Thank you so much for elaborating on the process.  I first came across the image on reddit where the OP posted.  The process was briefly explained and I understood it was a composite of two techniques.  IIRC, an ASI chip and telescope for the moon, and a Sony mirrorless and photography lense for the earthshine and starfield.  

 

I think the image is fantastic and I applaud the OPs creativity and talent.  I just think so much of the general public has been mislead to think that the image is just 50,000 photos stitched together to form a big 80MP image like a Gigapan, while the skillful application of different unique astrophotography techniques are not understood and unfortunately overlooked.  In otherwords, people are impressed for the wrong reasons.


Edited by Boom, 20 February 2019 - 10:31 PM.

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#5 Alen K

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Posted 20 February 2019 - 10:19 PM

A nice image but IMO the moon has been oversharpened.


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