first narrowband sho thoughts and comments

[iwols]

Hi just had my first go at sho and to be nonest its harder than rgb in some ways and very much personal taste,any way approx 40 mins of each filter,just wondered what your thoughts were and how it can be improved thanks

[iwols]

and my 3 masters if anyone fancies showing me what i might be able to achieve thanks

 

masterLight_BIN-1_1391x1039_EXPOSURE-300.00s_FILTER-HA_mono_autocrop.xisfmasterLight_BIN-1_1391x1039_EXPOSURE-300.00s_FILTER-OIII_mono_autocrop.xisfmasterLight_BIN-1_1391x1039_EXPOSURE-300.00s_FILTER-Sii_mono_autocrop.xisf

[Elp]

Some good detail for short time. Have you assigned them correctly to Hubble pallette (is that what you were going for?), S2 is red, HA is green and O3 is blue?

To get a "true" Hubble pallet scheme where it's a yellow/orange mid blue colour scheme, once your RGB is a combined colour image you usually have to do a green noise removal operation and magically the Hubble pallette usually appears. Then a few hue saturation passes will get you the colour saturation you're looking for.

It's all subjective anyway, not really a right and wrong way as long as you're happy with it.

[iwols]

thanks Elp i did assign them like that, didnt do the green extraction though,probably needs that,how do i do that in pi please

[Elp]

No idea as I don't use it. It's one/two button presses in Siril.

[Adreneline]

16 minutes ago, iwols said:

how do i do that in pi please

SCNR will remove the green from the image; some like to remove it all (1.0), some like to leave a trace (0.9). If you invert the image and apply SCNR at 1.0 it will remove the magenta which often occurs as star halos - again a matter of personal choice/preference. Once green is removed some like to boost the blue and the yellow/gold regions using ColourSaturation and/or CurvesTransformation.

[iwols]

just a quick reprocess with green removal any thoughts(thanks Adreneline and Elp

[symmetal]

I found this tutorial very useful on PI SHO processing and is what I used for my Pelican Nebula. 🙂

Alan

[iwols]

thanks symmetal and lovely pelican i can only dream😃

[Adreneline]

1 hour ago, iwols said:

anyone fancies showing me what i might be able to achieve

I do think it is better without the green BUT that is entirely personal taste.

I had a very quick go in PI with green and magenta removed but only minimal boost to blue and yellow/gold:

As with all these images colours are all down to personal preference.

If you wish I can let you know my steps in PI to achieve the above - I am sure with more time it could be better.

Thanks for sharing your masters - it's always fun to have a play with other peoples data.

Adrian

[iwols]

thanks Adrian thats nice, if you could share your steps that would be great,being a pi newbie 

[carastro]

I don't use Pixinsight so couldn't open the files.

rest of posted deleted as made a mistake. 

 

 

 

 

Edited June 23, 2023 by carastro

[Adreneline]

25 minutes ago, carastro said:

If you remove the green you have nothing to convert to yellow

Hi Carole

SCNR is Subtractive Chromatic Noise Reduction (SCNR) - it is designed to perform noise reduction and in particular to remove colour casts.

There's still plenty of green left in the image as per the histogram:

Without SCNR (and inverted SCNR) the histogram for the image is ...

... so it is pretty clear what SCNR has done - the main body of the histogram is largely unchanged.

I should have been more careful with my choice of words and said use SCNR "to remove the green (and magenta) colour cast".

Adrian

Edited June 23, 2023 by Adreneline

[Adreneline]

29 minutes ago, iwols said:

if you could share your steps that would be great

I'll PM you later rather than add to this thread  

[carastro]

Apologies, I got SNCR mixed up with HLVG.  

Carole 

[iwols]

1 hour ago, Adreneline said:

I'll PM you later rather than add to this thread  

thats great Adreneline look forward to it😀