Advice on processing

[StuartT]

10 hours ago, ollypenrice said:

My feeling is that the proper Hubble pallette is perfectly valid as a colour map of gas distribution. That's why it was invented. SII is mapped to red, Ha to green and OIII to blue, so it's a full tricolour system. A geology map might map different rock types to different colours. There is no resemblance intended between the natural colour of the gas or rock and its colour in the image.

'Fake' Hubble Palettes don't have this validity but people like making images that way because they like the way they look, which is fine by me, though I don't do it myself. If they are bicolour they are not, in truth, Hubble palette at all, they just end up with similar colours. In truth I think you can tell bicolour from tricolour anyway because there is a more restricted gamut in bicolour.

The other way to exploit NB data is to use it to enhance the colour channel in which it really belongs, so Ha to red and OIII on the green-blue border.

Olly

thanks so much for this. I'd never heard of the hubble palette before, but google is my friend and I have now found a bunch of videos showing how to do that with an OSC. It seems that to really do the Hubble palette you need 3 channels of mono data with HSO filters, but it looks like there is a kind of 'fudge' for those of us with OSCs by using the 'selective colour' feature in Photoshop.

Edited October 5, 2021 by StuartT