blog:photography:night:2021_10_25

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blog:photography:night:2021_10_25 [2021/10/30 21:53] – [Images] johnblog:photography:night:2021_10_25 [2021/11/06 10:11] (current) – [Images] john
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 <imgcaption 1|EOS 200D, Tokina f/2.8, 11mm, ISO3200, 6 x 120 seconds, processed from RAW>{{:blog:photography:night:2021_10_25:final_2.jpg?550|}}</imgcaption><imgcaption 1|EOS 200D, Tokina f/2.8, 11mm, ISO3200, 1 x 120 seconds, uncorrected JPEG>{{:blog:photography:night:img_3759.jpg?550|}}</imgcaption> <imgcaption 1|EOS 200D, Tokina f/2.8, 11mm, ISO3200, 6 x 120 seconds, processed from RAW>{{:blog:photography:night:2021_10_25:final_2.jpg?550|}}</imgcaption><imgcaption 1|EOS 200D, Tokina f/2.8, 11mm, ISO3200, 1 x 120 seconds, uncorrected JPEG>{{:blog:photography:night:img_3759.jpg?550|}}</imgcaption>
  
 +There was a fairly lurid coloured moon this night, so I also switched out to my only other lens available my 105mm Sigma macro:
  
 +<imgcaption 1|EOS 200D, Sigma f/2.8, 105mm, ISO200, 1 x 1/60 seconds at f11, processed from RAW>{{:blog:photography:night:2021_10_25:img_3788.jpg?550|}}</imgcaption><imgcaption 1|EOS 200D, Sigma f/2.8, 105mm, ISO200, 1 x 1/60 seconds at f11, centre crop>{{:blog:photography:night:2021_10_25:img_3788_centre_crop.jpg?550|}}</imgcaption>
 ==== Image Processing Notes ==== ==== Image Processing Notes ====
  
-Since this was my first time stacking and processing multiple images, it took a while until I found a solution that **(a)** worked properly on Linux, **(b)** I was comfortable with and **(c)**, happy with the output from.+Since this was my first time stacking and processing multiple images, it took a while until I found a solution that **(a)** worked properly on Linux, **(b)** I was comfortable with and **(c)**, was happy with the output from.
  
-First I tried [[https://siril.org/|Siril]], but I just couldn't get to grips with the interface - I found it entirely unintuitive. Then I tried [[http://deepskystacker.free.fr/english/index.html|DeepSkyStacker]] which, although Windows only, seemed to load and run via //Wine//, but ended up crashing repeatedly when processing images. Eventually I looked at [[https://www.hnsky.org/astap.htm|ASTAP]] which did everything I wanted and was clearly laid out.+First I tried [[https://siril.org/|Siril]], but I just couldn't get to grips with the interface - I found it entirely unintuitive **and** the tutorial to stack your images just would not run - throwing an error about a line in the pre-processing script which made no sense 
 + 
 +Then I tried [[http://deepskystacker.free.fr/english/index.html|DeepSkyStacker]] which, although Windows only, seemed to load and run via //Wine//, but ended up crashing repeatedly when processing images.  
 + 
 +Eventually I looked at [[https://www.hnsky.org/astap.htm|ASTAP]] which did everything I wanted and was clearly laid out.
  
 I tried loading images into the applications as the came from the camera, but all of my results were over-exposed, suffering varying levels of optical aberrations and just generally didn't look particularly great - even though stacking brought out far more detail than I had seen before. I tried loading images into the applications as the came from the camera, but all of my results were over-exposed, suffering varying levels of optical aberrations and just generally didn't look particularly great - even though stacking brought out far more detail than I had seen before.
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 Eventually I settled on the following routine (which works well for me, in my fairly light-polluted garden): Eventually I settled on the following routine (which works well for me, in my fairly light-polluted garden):
  
-   * Load RAW files into Rawtherapee and adjust as follows: +**1. Load RAW files into Rawtherapee and adjust as below*
-   * {{:blog:photography:night:2021_10_25:rawtherapee-initial-exposure-settings.png?200|}}{{:blog:photography:night:2021_10_25:rawtherapee-initial-chromatic.png?200|}}+ 
 +{{:blog:photography:night:2021_10_25:rawtherapee-initial-exposure-settings.png?300|}} {{:blog:photography:night:2021_10_25:rawtherapee-initial-chromatic.png?300|}} 
 + 
 +//The chromatic aberration settings are likely particular to my lens which is of course in this case is the ultra-wide 11mm Tokina. At 11mm and f/2.8 it has quite bad chroma in the corners of the image. It would likely not need such aggressive settings stopped down, or at the other end of it's focal length (16mm).// 
 + 
 +**2. Save as TIFF, 16bit. Load into GIMP and apply gradient as below in the direction of any light pollution** 
 + 
 +{{:blog:photography:night:gimp-gradient-settings.png?200|}} {{:blog:photography:night:gimp-applying-gradient.png?600|}} 
 +    
 +//Depending on the level of light pollution, increase/decrease the opacity of the gradient, as well as the length it is applied to.// 
 + 
 +**3. Load all of the processed TIFF files into ASTAP as your light files. There will be some warnings about missing metadata, but this doesn't appear to impact the final image.** 
 + 
 +**4. Let ASTAP do the stacking, along with any dark, flat and bias images.** 
 + 
 +{{:blog:photography:night:astap-stacking-settings.png?600|}} 
 + 
 +//For me, the best results were with the AstroSimple option and Sigma Clip stacking options as above.// 
 + 
 +**5. In the resulting stacked image, if the star colours look //off//, try another stacking/colour de-mosaic algorithm, or try the 'Autocorrect image colours' option from the tools menu.** 
 + 
 +**6. Export as TIFF from ASTAP and load back into your image editor of choice. I used Rawtherapee to do final image/colour enhancements; playing with the colour and black/white highlight balance.**
  
 +{{:blog:photography:night:rawtherapee-final.png?600|}}
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  • Last modified: 2021/10/30 21:53
  • by john