PixInsight Forum (historical)
PixInsight => Gallery => Topic started by: Richard Christy - DarkSky|AP on 2017 July 16 14:58:47
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Finally figured out how to stack lunar in PixInsight! So far I am loving the results.
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Hi Rich - that is a really nce image!
Would you care to share some details with us? For example, what equipment did you use to capture it, and how many exposures di you take (and of what Exp. Time, and with which filters, if any)?
Then, we would love to know the steps you used to pre-process (calibrate, align and stack) to create your master image, followed by what you then did in post-processing to generate your masterpiece.
Fpr all of us patiently waiting for darker nights to return, I am sure that a lunar challenge should keep us entertained!
Well done :)
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+1 to everything above - please share!
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Thanks for the kind word! I may have oversaturated the color a bit. I do all of my processing on a 4kx2k monitor which is calibrated for photos. I should have viewed it on a normal monitor before posting it 😊
Yes, I will be happy to explain all the details. I started putting it together in a word doc. Once I finish the workflow I will post all the details!
Thanks,
Rich Christy
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Telescope:
Celestron EdgeHD 8’’ with focal reducer
Camera:
ZWO ASI1600MC-Cool for RGB
ZWO ASI1600MM-Cool for Narrowband
Filters:
Optolong Sii + Oiii for blending in with RGB (will explain the reasoning as we get to this part)
Starting off tried to achieve the best focus possible given the conditions and instead of taking single exposures, I shot it as a video clip. Roughly 10min of video.
Exported the video clip into single frames and sorted them by quality. I am sure there is other software that can do this, but I used AutoStakkert_2.5.1.7 to handle the sort and export into individual frames. Once I had them, everthing else was done with PixInsight magic!
Part One: Alignment and Image Integration
StarAlignment
Reference Image
1) Picked my reference image
2) Checked distortion correction with default values 0.005 and 20 for distortion iteration
3) Generate drizzle data
Target Images
1) Add my target images (out of 1000+ images, I picked 250)
Star Detection
1) Detection scales set to 8
2) Max Distortion set to 0.100
Interpolation
1) Pixel Interpolation: Lanczos-4
2) Clamping: 0.30
Use this for RGB, Sii, Oii data
Image Integration
Input Images
1) Add aligned images and drizzled files if you picked drizzle
Image Integration
1) Average
2) Additive
3) Noise Evaluation
4) Iterative k-sigma / biweight midvariance
5) Generate integrated image
6) Generate drizzle data
Pixel Rejection (1)
1) Rejection Algorithm: Windsorized Sigma Clipping
2) Normalization: Scale + zero offset
3) Clip low pixels, clip high pixels
4) Clip low range, Clip high range (I never check these for DSO projects. However for lunar I found this to work better than not checking)
5) Report range rejection
Pixel Rejection (2)
1) Sigma Low: 6.000
2) Sigma High: 4.200
(depending on quality/noise you may need to tweak these settings. I found the above settings to work well with my data)
3) Range low: 0.00
4) Range high: 0.98
Same settings for the three data sets – RGB, Sii, Oii
PixelMath
R/K: Sii
G (0.5*Sii)+(0.5*Oiii)
B Oiii
a) Create new image
b) Image Id: Give it a name
c) Color Space: RGB
You should now have two images in hand. One that is RGB and the other in RGB with the narrowband data.
Will put together and post part two which walks through all the processing steps to achieve the final results. More to come....
Rich Christy
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How does it align without stars? I would like to compare the results using PI and Registax or Autostakkerd 2.
Rodd