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john2y

IC410 Tadpoles SHO

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About a month ago I started gathering data for this gorgeous nebula. I prioritised this one over the Flaming star since I really like the blue oxygen pool in this one. Honestly I didn't think it would turn out this good. I'm shooting from the balcony in the center of big city from the red zone and even in narrowband the difference in seeing comparing to countryside is huge since the city has much more dust particles in the air and pollution. 

So far I've gathered 139x3min of Ha, 154x3min of Oiii and only 40x3min of Sii, I'm planning on adding around 100 exposures of sulphur and 40 to Ha and Oiii to be done with this nebula. The reason I'm posting it already is that the two week streak of clear nights has ended for me and according to the forecast I won't be shooting at least a week or so, so I've decided to process it just to see how it looks with the data I have now. 

Equipment used: Explore Scientific AP 102/714 ED APO Triplet with 0.8x flattener and ASI1600MM Pro with ZWO NB Filters, Processed in Pixinsight

Clear skies

Jan

 

 

tadpoles_fullres.jpg

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Very string image and very well processed. I particularly like the central core contrast in colours.

I see you processed in PixInsight - can you tell me which combination method you used, and if it was PixelMath, what setting you used for each channel?

Thanks - and again, really well done.

One more thing, what is this "...2 week streak of clear nights" you speak of....I've never experienced such a thing LOL!

David

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Thank you, I used regular LRGB combination and assigned sulphur to red, hydrogen to green and oxygen to blue, that's why it's SHO combination. Then I stretched it and played a lot with the colour masks to get rid of the abundant green and magenta. As a final touches I did star reduction, lightness and chromatic denoise. I would also sharpen the image a bit but I'm still lacking the data to do so since the sharpening increases noise in the fainter parts of the nebula. 

Regarding the weather I live in south part of the Czech Republic and from what I read here I have much better weather than you guys in England 

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1 hour ago, john2y said:

Thank you, I used regular LRGB combination and assigned sulphur to red, hydrogen to green and oxygen to blue, that's why it's SHO combination. Then I stretched it and played a lot with the colour masks to get rid of the abundant green and magenta. As a final touches I did star reduction, lightness and chromatic denoise. I would also sharpen the image a bit but I'm still lacking the data to do so since the sharpening increases noise in the fainter parts of the nebula. 

Regarding the weather I live in south part of the Czech Republic and from what I read here I have much better weather than you guys in England 

Yes, the majority of our fellow amateur astronomers have better weather than we have in England, they're sane and pursue the hobby where the weather is agreeable, only a madperson and the English would attempt star gazing here LOL!

I get the SHO acronym, I use the same approach in PixelMath only with different weights to each channel/combinations of channels etc.

I've tried LRGBCombination and it worked well once but not, for me anyway, as well as PixelMath. But it (lrgbcombination) certainly and undeniably worked well on yours! 🙂

Have you tried SCNR to remove green - I'm sure you have but thought I'd mention it just in case - PixInsight has so many facilities I'm always learning about new ones on here 🙂

What do you plan to use for sharpening when you get enough data - I've not attempted much of that outside of LocalHistogramTransformation (contrast enhancement)

David

 

 

Edited by David_L
added the text "(contrast enhancement)"

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I used to do it in pixelmath too, especially when I used modded dslr with Ha and Oiii filter to make synthetic green channel to create fake SHO image but now it just gives me really ugly stars. I do the LRGB combo twice, first I simply combine r,g,b data without chrominance noise reduction, do an unlinked stretch and extract the luminance layer from the image and use is as L component in LRGB (only L is checked) and apply it to the previously combined image now with chrominance noise reduction checked. 

I use SCNR but it would still leave the image with a lot of magenta around stars and also I think it's easier to convert the green to yellow using colour mask. 

I sharpen images either with Unsharp Mask or more frequently with Multiscale Linear Transform using layers 2 and 3 and increasing their bias to 0.1 and 0.05 and applying it to the image with mask applied to protect the dimmer parts. 

Jan

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29 minutes ago, john2y said:

I use SCNR but it would still leave the image with a lot of magenta around stars

Tip for this: invert and apply SCNR then invert back

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16 hours ago, moise212 said:

Tip for this: invert and apply SCNR then invert back

Thank you, I'll definitely try it but maybe not on SHO images since I still use colour mask to tweak the colours. 

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1 minute ago, john2y said:

Thank you, I'll definitely try it but maybe not on SHO images since I still use colour mask to tweak the colours. 

But you get magenta stars only in SHO images. Inverted magenta is green so SCNR will remove it

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17 hours ago, peter shah said:

Very deep shot beautifully captured

Thank you! 🙂

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+1 for scnr on inverted image to remove magenta halos.

Marvellous image Jan with lots of dust detail.  Will be interested to see whether the extra SII adds anything.  

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2 hours ago, MartinB said:

+1 for scnr on inverted image to remove magenta halos.

Marvellous image Jan with lots of dust detail.  Will be interested to see whether the extra SII adds anything.  

Thank you! I'm thinking about adding around 4-6 hours of Ha too to smooth out the nebulosity that it around it. 

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A little followup, I've managed to add more Ha so far and the image looks a bit cleaner, I lost a little bit of oxygen though because of more strict frame selection during preprocessing. 

tadiky.jpg

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That’s class. I agree the new version is a step up, both are class though 

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1 hour ago, tooth_dr said:

That’s class. I agree the new version is a step up, both are class though 

Thank you very much! It's still work in progress but hopefully it'll be finished soon. 

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I like this and the second version just shines through :) 

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3 hours ago, swag72 said:

I like this and the second version just shines through :) 

Thank you, as I'm writing this I'm finally capturing another Sii data.

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