PixInsight Forum (historical)

PixInsight => General => Off-topic => Topic started by: Nigel Ball on 2010 September 11 08:17:33

Title: Combining Ha and OIII
Post by: Nigel Ball on 2010 September 11 08:17:33

Hello all

I've been happily processing my Ha and OIII subs in PI and I've even saved my first Process Icon  :D The Morphological Transformation tool wokred overtime on this wide field shot .....

Once I've got the images ot a decent state I'll want to combine them into RGB and generate a synthetic Green channel or create one using the Ha and OIII

I've had a good look through the forum but cant seem to find anyhting on this

Any thoughts / directions ?

Thanks

Nigel

Title: Re: Combining Ha and OIII
Post by: Silvercup on 2010 September 11 10:58:57

Hi Nigel:

I used to do this pixelmath expresion:

R: H-Alpha
G: sqrt(H-Alpha*OIII)
B: OIII

Or you can play with percent in the green channel, for example:

R: H-Aplha
G: H-Alpha*0.15+OIII*0.85
B: OIII

Best. Silvercup

Title: Re: Combining Ha and OIII
Post by: Nigel Ball on 2010 September 11 15:22:18

Thanks Silvercup

My first attempt produced a rather dirty yellow for the Ha using 0.8 Ha + 0.2 OIII  :-[

I'll need to tweak the ratios to get a decent colour

Would I use PixelMath again to add the Ha on top of a RGB image for Luminance?

So many questions .....

Nigel