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Making progress: Cocoon Nebula 2018 vs. 2021 version

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#1 the Elf

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Posted 15 September 2021 - 03:02 AM

Dears,

 

the last time I imaged the Cocoon nebula was back in 2018. At the time I got my new EQ6-R. So I happened to mix Ha data taken on the AVX and OSC data taken on the EQ6-R. Collecting 11h was one of my longest integration times. The result was far better than my first attempt a year before. Now, 3 years later the old unmodded T3i was replaced by a T7i. Most important after a summer without hardly any clear night all of a sudden 4 successive clear nights near new moon came up. I was able to collect 20h+. Last but not least I dared adding more color to the image.

 

2018:

C19_2018_low.jpg

 

2021:

C19_2021_low.jpg

 

Details and high res images here:

https://www.elf-of-l...Cocoon2021.html

 

C&C welcome. Thanks for looking!

 

CS

the Elf


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#2 sharkmelley

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Posted 15 September 2021 - 04:09 AM

That's a great result and the difference is very clear.  The dust comes out more clearly in the new version and the star colours look excellent!

 

Mark



#3 the Elf

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Posted 15 September 2021 - 04:28 AM

Thank you very much!

Star color is so rich thanks to arcsinh. Thank you for developing and sharing this great tool.


Edited by the Elf, 15 September 2021 - 04:29 AM.

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#4 nicknacknock

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Posted 15 September 2021 - 04:41 AM

Elf,

 

While the primary object is of course much better, I am drawn to many other things in the image:

 

1) star field in second image provides depth to the image

2) shows how there are stars of different phase / size / luminance in their lifecycles

3) shows a significant number of stars not present in the first image

4) actually manages to pull fainter nebulosity around the Cocoon, which shows as a "dark nebula" surrounding the Cocoon in the first image

 

All of the above make the second image look "alive" vs the first one which is - for the lack of better term - static / lifeless.

 

------------

 

Yes, I DID enjoy it that much to invest the time to type out my true impressions. Thank you for sharing! 


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#5 mdavister

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Posted 15 September 2021 - 06:40 AM

The 2018 version is good, the new 2021 is very nice. Love the color balance on the second, really accentuates the varied color temperatures of the various stars. Pulling the details out of the Cocoon, very well done.



#6 asanmax

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Posted 15 September 2021 - 04:29 PM

Terrific image! I always like it when the stars are not oversaturated in the images. It's hard to keep the colors at bay.



#7 the Elf

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Posted 16 September 2021 - 12:44 AM

Elf,

 

While the primary object is of course much better, I am drawn to many other things in the image:

 

1) star field in second image provides depth to the image

2) shows how there are stars of different phase / size / luminance in their lifecycles

3) shows a significant number of stars not present in the first image

4) actually manages to pull fainter nebulosity around the Cocoon, which shows as a "dark nebula" surrounding the Cocoon in the first image

 

All of the above make the second image look "alive" vs the first one which is - for the lack of better term - static / lifeless.

 

------------

 

Yes, I DID enjoy it that much to invest the time to type out my true impressions. Thank you for sharing! 

Thank you very much for your detailed feedback. I often see image I like and other I don't like that much but I cannot tell what exactly is the missing part. You absolutely nailed it with your analysis. The points you list explain why an image (not only this one but in general) looks alive or boring. I already understood that an illusion of depth is important. So far I was thinking the blue in false color NB data is the only way to create this illusion but indeed the star field does a similar job. Pulling out the dark nebula really needs plenty of data. The dark nebula in the Cygnus wall as well as the Horse Head are easy but in all other cases I utterly failed to bring out a dark nebula. This one is on the border to just showing up. Alas the clear nights are gone so for the time being I cannot add more data. Now I understand that more data is not only a difference in noise but also is the difference between a dark nebula showing up or not.

Thanks again!
 


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#8 vidrazor

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Posted 18 September 2021 - 02:06 AM

Nice. Did you mean to say T7i on your 2021 page? Skies are a bit cyan I think, but otherwise great render.



#9 the Elf

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Posted 19 September 2021 - 01:58 PM

T7i is sold as 800D in Europe. The mono mod is an US import thus it is a T3i and not a 600D. The different names are just confusing. No clue what Canon is trying to achieve.



#10 F.Meiresonne

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Posted 19 September 2021 - 02:04 PM

20+ hr is very long...seems a faint object then. Nice picture !

 

Actually on IC 1805 i went over 7 hours now...a record breaker...



#11 the Elf

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Posted 19 September 2021 - 03:26 PM

The challenge is to have enough background for the dark nebula to show up. I'm barley at the border of seeing it in the image. Also I like using the OSC cameras color data only (not mixing in any Ha to the red and blue channel) and it needs quite a bunch of OSC data to do this. Until now the noisy T3i and bad weather never allowed for this technique. Using Ha as a luminance booster only gives the image a far better color imho.



#12 the Elf

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Posted 20 September 2021 - 11:09 AM

While doing some backup I found an even older version back from 2017. So I checked for more and found the Cocoon is not the only triple. So I started this new thread:

 

https://www.cloudyni...ersions-please/


Edited by the Elf, 20 September 2021 - 11:12 AM.



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