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M63 with 16" Dobson , A7s and 19000 images using Siril

astrophotography CMOS dslr imaging Orion dob
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#1 diegoesep

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Posted 07 July 2020 - 05:34 PM

Hello,

 

Please find my M63 image processed with latest Siril version: stack of 18000 RAW full frame with A7s on Orion Dobson XX16g at 1800mm focal length:

 

M63 with XX16g, A7s and Siril

 

Full res: https://www.astrobin.com/full/ziu4um/

 

Optics and sensor:

  • Telescope: Dobson Orionx XX16g 16" with 1800mm focal length and coma corrector
  • Mount: Dobson OrionXX16g mount in altazimutal mode, no guiding
  • Capture: 19000 full frame RAW of 1 second duration with Sony A7s at 6400 ISO

Siril processing:

  • FITS compression: Used 32Bits float Rice FITS compression with a quantification factor of 32: the 18800 full frame RAW used 600Gb on the SSD disk instead of 2700Gb...
  • Preprocessing: 1000* darks 1s 6400 ISO with dark optimisation, offset and flats
  • Alignment: Global star alignment to handle field rotation of Dobson mount
  • Stacking: Linear fit using 18000 images from a total of 18800 (using 10000 increased the resolution but the SNR was not good enough )
  • Crop of the stacked image (field rotation)

Image was finalized with PixInsight. Please find below a rescaled example of one of the 1 second frame used for the stack to see the improvment of the stacking with a low read noise sensor and high number of frames:

M63 with XX16g, A7s and Siril

Clear skies,

Fabrice Faure

France


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#2 elmiko

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Posted 07 July 2020 - 05:42 PM

Incredible! You must have a huge amount of computer space!!!


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#3 sharkmelley

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Posted 08 July 2020 - 02:27 AM

What a tour de force!

 

The result certainly demonstrates what is possible to achieve with short exposures.

 

Mark


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#4 diegoesep

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Posted 08 July 2020 - 05:03 AM

Incredible! You must have a huge amount of computer space!!!

What a tour de force!

 

The result certainly demonstrates what is possible to achieve with short exposures.

 

Mark

Thanks Mike and Mark for your messages smile.gif

The A7s full frame 32bits FITS without compression are using 135Mb on disk so for 18800 images it would have taken 2700Gb without compression!
With the FITS compression feature that I have implemented in Siril, the 32 bits floating FITS image is using 30Mb with Rice compression using a quantisation factor of 32, taking 600Gb for all the images before stacking.

Siril fits compression is available in latest dev release (see https://gitlab.com/f...rge_requests/55 for more details).

 

Fabrice



#5 pbealo

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Posted 08 July 2020 - 05:28 AM

What was spec of computer used in this effort, and how long did full processing take? Great results!

Peter


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#6 lock042

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Posted 08 July 2020 - 06:47 AM

Very nice use of Siril :).

Congrats !!


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#7 sunnyday

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Posted 08 July 2020 - 08:26 AM

very successful, beautiful details, and colors.
well done and thank you.


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#8 AnakChan

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Posted 08 July 2020 - 08:29 AM

Really impressive! Dare I ask how in the world your computer processed 19000 subs + thousands of calib subs!?


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#9 erictheastrojunkie

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Posted 08 July 2020 - 10:01 AM

bow.gif

 

Mother of god, the whole scope of the project is kind of mind melting, a Dobson.....1" exposures.....TENS OF THOUSANDS of exposures. A truly spectacular image as a result, really well done!


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#10 calypsob

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Posted 08 July 2020 - 10:13 AM

Wow fantastic project. The stars in the dob are perfect.
Might be easier in the future to go to a cooled cmos that allows ROI sampling of the sensor!
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#11 asanmax

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Posted 08 July 2020 - 11:40 AM

Amazing! I had to re-read the acquisition details, 19K of 1 second exposures, unheard off.


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#12 Starman27

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Posted 08 July 2020 - 01:10 PM

Absolutely stunning!


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#13 diegoesep

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Posted 08 July 2020 - 01:15 PM

Very nice use of Siril smile.gif.

Congrats !!

very successful, beautiful details, and colors.
well done and thank you.

bow.gif

 

Mother of god, the whole scope of the project is kind of mind melting, a Dobson.....1" exposures.....TENS OF THOUSANDS of exposures. A truly spectacular image as a result, really well done!

 

Wow fantastic project. The stars in the dob are perfect.
Might be easier in the future to go to a cooled cmos that allows ROI sampling of the sensor!

 

Amazing! I had to re-read the acquisition details, 19K of 1 second exposures, unheard off.

 

Absolutely stunning!

Thanks ! All your messages motivate me to finalize my next image with the same process ! smile.gif


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#14 diegoesep

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Posted 08 July 2020 - 01:28 PM

What was spec of computer used in this effort, and how long did full processing take? Great results!

Peter

 

Really impressive! Dare I ask how in the world your computer processed 19000 subs + thousands of calib subs!?

Thanks!

In fact the most important part of this project that allow to process these 19000 subs is not the hardware but the software that I am using: Siril

I didn't manage to process in a reasonable amount of time this number of DSLR full frame with other astronomy software.

The latest version includes a lot of optimisations for DSLR RAW frame conversion to FIT, preprocessing , alignment and stacking using all the available CPU cores in parallel, include the FITS format compression.

Excepted the fact that I am using a 1Tb SSD and a CPU with 4 cores/8HT (Xeon E3 1270V3 equivalent to Core I7 4770) the desktop PC that I am using for the processing is not very high end by nowadays standards.

Preprocessing/alignment of the 18000 images took around 6 to 8 hours but it was done only one time and can launched the night before thanks to Siril scripting.

The final stacking of the image using normalisation with Linear fit clipping has taken 14 hours, but most of the stacks done before the final one with non rejection on 18000 images took around 1 hour.


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