NGC 1491 / Sh2-206 in Perseus in Ha / OIII / OIII bicolour

[x6gas]

I've been playing around with this image quite a bit since capturing some OIII to go along side the Ha.  I can't seem to hit the sweetspot with the sky colour on this; it seems either too green, too purple or, as in this case a tad too red?  Matching up the blackpoints on the histogram results in way too much blue.  Any suggestions?

Data is 24 x 1200s Ha and 12 x 1200s OIII, combined as HOO.

Scope: Takahashi FSQ85EDX

Mount: CGEM DX

Camera: Atik 490ex

Guiding: IMG0H; Atik OAG; PHD

Clear skies, Ian

[sologuitarist61]

I don't know if this is any better, but I have made the dark of the sky as black as possible but finding an area clear of star and using the 'black' button in 'Levels', so at least we know the black is black if you see what I mean, but still a lot of red in the image.

The tried the same thing with the white pointer on the bright star just to the left of centre and got this which is radically different!

[iksose7]

Hi Richard, i think the first version is by far the best, not too keen on that last version at all if i'm honest! I would say lift the black a bit to make the background a bit brighter. Also, do the black points have to match? I used to think so but nowadays i find that sometimes matching them all creates a mess, especially with the blue like you said. When adjusting them i focus on what the image looks like rather than where i am moving the channel slider, seems to work better for me

[sologuitarist61]

I agree the second image is not good but I showed it just for the effect it achieves.

To lighten a dark background a bit in later versions of Photoshop under Image>Adjustments their is a Shadows and Highlights setting and you can drag the Shadow setting to lighten the black and this will show the less well defined stars brighter. Below is my first image with the shadows slider set to 35

[sologuitarist61]

Ooops forgot image