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Old 02-10-2023, 07:44 PM
carlstronomy (Carl)
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Filter Questions M42

So, starting with confused

I have recently taken ownership of my ASI294MC, I have been very happy with the results once the images have been stacked.

Until I used my L-eNhance filter during the full moon. I wanted to see how well it did with my light polluted skies. I found out it does very good indeed but I have no idea how to stack the fits.

Deep Sky Stacker - I tried many different methods but everything came out red like the image attached.

I used the ASI Deeps Sky Stacker - This did much better I had colours in the image attached but still not as controllable in photo shop as I would like.

Now I know that this filter allows and blocks different light wave lengths than an IR cut filter which will change my image. The issue I have is the fits I have show good colour. I have attached one of my fits.

Why is DSS killing my image when the correct data is there prior to stacking. In all my experiences with stacking, the stacking software works with the data you have in the subs. Why is the data being changed so much during stacking. Please note the RGB's are aligned it is just pure red almost.

I can understand it if my fits were already red but not when they are correct.

Any advice would be great as I seem to missing something.

Clear skies

Carl
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Click for full-size image (M42 ASI Upload.jpg)
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  #2  
Old 02-10-2023, 07:57 PM
raymo
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When you say that the RGB are aligned, are you referring to the sliders, or
the RGB cones in the DSS histogram?
raymo
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  #3  
Old 02-10-2023, 08:33 PM
carlstronomy (Carl)
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RGB in the histogram are all aligned and the sky is even also, nice and black and reading as such. Just a lot of red in the nebulosity. Seems strange that it is only doing this in DSS and ASI stacker was not doing the same thing.

There is one positive to take out of my first outing with this filter is my flats and dark flats worked a treat, the images are great for a full moon sky.
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  #4  
Old 03-10-2023, 01:05 PM
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AstroViking (Steve)
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Give your data a try with Siril, and maybe Sequator, too.

I've found that different stacking software gives different results, and that Siril gives me the best looking image.

V.
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  #5  
Old 03-10-2023, 04:58 PM
ronson
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The FITS viewer shows you what it thinks is the correct color via a quick linear stretch. Depending on how it does the stretch, the preview will differ from one FITS viewer to another. I wouldn't judge color representation from a FITS preview. More mature processing tools have photometric color calibration capabilities to help as part of the processing workflow.

But given your image is in dual narrowband, your filter captures Ha and Oiii, and your target is Ha rich, red color is not far fetched result.

In post-processing you can adjust the color as you see fit. Some split the Ha and Oiii channels and process separately to taste. Everyone to their own
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Old 03-10-2023, 05:11 PM
carlstronomy (Carl)
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Thanks guys, yes tried Siril last night. First time using it and it gave much better results than DSS when using the L-Enhance but using the normal IR cut DSS did better than Siril. Go figure

I did not realise the FITS preview was stretched thanks for that info, I assumed it was like my CR2 files from my Canon.

Looks like I need to learn to split some channels, here comes Dr Google

Thanks Heaps, still glad I moved up from DSLR but much to learn.

Clear Skies
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