I finally got together all the narrow band data on this object over the last week or so. Total integration is 19 hours.
I have been trying to find a way to use narrow band data to produce RGB stars (as several other images do exactly that) and I think I have managed to get a reasonable facsimile. It involves a bit of trial and error but essentially I combine the Ha SII OIII to RGB. Then colour match the whole image to what it ought to look like in RGB. Then copy and paste this image onto the NB image and use lighten mode for blending mode. Finally use replace colour tool and highlight the red/orange stars and then adjust that colour to a more yellow colour. You can do this by selecting the stars only too and then just adjust the opacity.
Things that I find are missing using only NB data though is the luminance in the cloud data you get from using the actual luminance data. There is also the natural charcoal look to the sky which is missing and the colours of the RGB nebula which gives a pleasing look to all the gas and dust.
That is really nice Paul, blows the socks off my first run detail wise! Guess that's the difference between a 5.1" and a 12"
I hadn't actually thought of trying to create synthetic RGB stars with the narrowband data, I'll have to give that I shot when I get home. Get more data too!
really nice work paul. thanks also for sharing the NB mapping to rgb stars method. I might give it a try sometime, could really be useful with Melbourne's weather!!!
Very Nice Paul - I really like the colours and details on this version and that star technique you've described is a stroke of genius!
Well done & thanks for sharing
Paul, I cannot even begin to say how seriously good that image is. The thing that is most striking is the incredible contrast in the bright nebulosity. Very well done.
I've thought a lot about how to use NB data to "guess" what the natural colour of the star might have been. Just thinking of the physics, the only meaningful information we have is an estimate of red to blue: (Ha + SII) / OIII. So one physically meaningful approach would be to map high ratios to red, low ratios to blue, and middling ratios to orange, yellow, and white.
I would imagine that the way to proceed would be to:
(a) Go starless, or at least approximately so.
(b) Separately, on the linearly and equally stretched original image, come up with a set of star colours as described above.
(c) Drop the star colours onto the starless image, using "lighten" mode.
Working on it!
Once again, that is a completely stunning image, most especially in terms of the skilful use of high contrast in the nebulosity.
A very nice image Paul and good to see the star colour correction worked out well. I like how you got the "Twister" to be blue as it is fairly prominent in O111.
Paul, I cannot even begin to say how seriously good that image is. The thing that is most striking is the incredible contrast in the bright nebulosity. Very well done.
I've thought a lot about how to use NB data to "guess" what the natural colour of the star might have been. Just thinking of the physics, the only meaningful information we have is an estimate of red to blue: (Ha + SII) / OIII. So one physically meaningful approach would be to map high ratios to red, low ratios to blue, and middling ratios to orange, yellow, and white.
I would imagine that the way to proceed would be to:
(a) Go starless, or at least approximately so.
(b) Separately, on the linearly and equally stretched original image, come up with a set of star colours as described above.
(c) Drop the star colours onto the starless image, using "lighten" mode.
Working on it!
Once again, that is a completely stunning image, most especially in terms of the skilful use of high contrast in the nebulosity.
Best,
Mike
Thanks Mike for the comments. There are certainly a number of ways to approach the problem of star colour in NB. Martin Pugh told me a detailed method he uses at a Malin awards quite a few years ago but I have forgotten his method. It did not involve any process I have read but it I think it does use the colour match tool. His star colours are very consistent. It means not having to collect RGB.
Also thank you (and Mike) for sharing your approach to colouring stars; I will certainly try it since RGB data collected with my doublet is substandard.
Very keool scene & naturally presented Paul, heaps of detail and the brighter central areas are powerful with the 3D effect, just astonishing really when peer in there a while
Grouse stuff again
Also thank you (and Mike) for sharing your approach to colouring stars; I will certainly try it since RGB data collected with my doublet is substandard.
Thanks Suavi, a synthetic approach will no doubt help you if you have trouble with RGB. I'll have to do more experimenting to get a consistent result.
Quote:
Originally Posted by astronobob
Very keool scene & naturally presented Paul, heaps of detail and the brighter central areas are powerful with the 3D effect, just astonishing really when peer in there a while
Grouse stuff again
Thanks Bob, that is sort of what I was aiming for with this image. I was surprised by the clouds to the left which took on a 3D look after some contrasting processing. There is always some little surprise to be had with imaging, even of the most commonly imaged objects.
