Pelican nebula - colour B&W comparison images

[fwm891]

Shot these images back in April and have been playing with them in DSS and PS CS3 on and off since then trying to 'see' which treatment gave the best detail...

Still not sure as to me the colour emphasises some detail and grey shading others - what do others think?

[Shibby]

Hmm, to me, the greyscale image looks much more detailed. Having said that, the very faint stuff (top right) seems more visible in the red image; I'd have though it would be the other way around!

[roundycat]

Unless you are able to give each frame set an identical process in PS which is bordering on impossible due to background brightness and exposure differences you will never be able to compare the two on an equal basis.

I think there is some reflection nebulosity to be picked up with a blue filter and it will only show as a very faint grey. No difference between to faint shades of grey but equally faint red and blue are very different.

To get the best from this object you need to use narrowband filters, they really do accentuate the differences in the various gases.

Dennis

[fwm891]

Lewis / Dennis - Thanks all comments valuable. Agree about narrow cut filters, until you know who with the purse string thinks I have enough brownie points I'm having to make do... H-alpha first on the list. My Baader UHC-S filter gives 3 well defined colour channels in PS so I can separate those, its the Ha needed for clean luminance content, or atleast thats my thinking at the moment - you may change my mind?

[roundycat]

If you can get a good colour signal (you can tell if it is really good, it needs hardly any stretching) the luminance is an inherent part of that. Luminance only really comes into its own when you are struggling with the colour. Then the L can give the picture good structure.

Dennis

[fwm891]

Dennis - Thanks. Getting good colour (sodium's OK) around Reading is nigh on impossible. I hope you have better skies around Harwich (unless your near the docks I seem to remember things being quite rural!)...