M101 - Pinwheel Galaxy - LRGBHa - 30/4/13

[ollypenrice]

Lots to admire, Gina.

I'm very surprized to read that you are adding Ha to luminance. To my mind, on most galaxies, the Ha really only traces a serious of rather formless and blob-like HII regions of star formation and doesn't have much to say about the rest of the structure in the galaxy. I would keep it well away from the luminance for this reason. I'd add it to red in BM lighten, as you did in the reprocess and, as Rob says, it can work as a surragate H beta in blue. I've done that on nebulae but not galaxies and will also be giving it a whizz!

I don't feel your RGB is properly in play yet. I think it's being overwhelmed by the lum. There's a simple way to get more out of it. Add the L to the RGB in blend mode luminosity but stop at about 20%. Boost the saturation, flatten and reduce the noise. (Try a variety of filters, Gauss, NR, Noel, whatever...) Then re-apply the L to this at a higher percentage and repeat. This often works better than trying to dump on the Lum in one iteration.

I sharpen as Rob does, pretty well. I'll do a global sharpen, paste it underneath and erase the top unsharpened layer where the signal will stand it. I also do the same for noise reduction, applying it relluctantly and selecting only the bits that need it using layers and eraser. We all know the best way to reduce noise!!!

I must admit to not using a layer mask for letting the sharp or noise reduced layer through. I just soft-erase the top layer directly. This is probably bone idle and I need to look into it! Personally I would far rather select the zones for shapening and noise reducing this way, in layers, by looking at it myself than using the PI method of trying to persuade the software to mask what I want it to mask.

I'd try a luminance unadulterated by Ha. I may be entirely wrong but I think it will be sharper, especially in the core.

Astrodon Ha filter, no less? Hark at you!!!

Olly

[Gina]

Thank you very much for your advice Olly I'll have another go at it I quite like processing now that I have a reasonably fast desktop with quad core processor running Win 7 Pro 64bit.

Here's the stacked and processed Ha if you're interested.

[RobH]

I agree with Olly re. the colour Gina.

The other thing to do now is to get rid of the sharpening halos around the stars.

Again, this is an easy one.

After you've sharpened, but before you do anything else at all, go to....EDIT/FADE SHARPEN

This will bring up a window. Change the mode to LIGHTEN.

This decreaases the sharpening effect somewhat, so you need to add a bit more initially than you normally would, but it'll remove all of the halos etc.

Cheers

Rob

[ollypenrice]

Thank you very much for your advice Olly I'll have another go at it I quite like processing now that I have a reasonably fast desktop with quad core processor running Win 7 Pro 64bit.

Here's the stacked and processed Ha if you're interested.

That surely can't be doing your luminance any good. You want the L for the delicate spiral structure in the core, yet the Ha is just black there so it will certainly dilute the real L if you blend them. Or so I'd say.

Olly

[Gina]

I agree with Olly re. the colour Gina.

The other thing to do now is to get rid of the sharpening halos around the stars.

Again, this is an easy one.

After you've sharpened, but before you do anything else at all, go to....EDIT/FADE SHARPEN

This will bring up a window. Change the mode to LIGHTEN.

This decreaases the sharpening effect somewhat, so you need to add a bit more initially than you normally would, but it'll remove all of the halos etc.

Cheers

Rob

Thank you Rob - I'll try that

[Gina]

That surely can't be doing your luminance any good. You want the L for the delicate spiral structure in the core, yet the Ha is just black there so it will certainly dilute the real L if you blend them. Or so I'd say.

Olly

I expect you're right I shall be having another go at the processing. I'm not sure whether to collect some more data on this object or move on to untried targets. My initial feeling is to try something else.

[Gina]

OK I've removed the Ha from the Lum and applied the other techniques I've recently learnt Don't think it's quite right though.

[Ewan]

That is one nice M101 Gina, even more detail coming through near the core, pleasing colours as well.

[Gina]

Thank you Ewan

Another reprocess with more tittivating.

Note... Just noticed that I didn't crop the final image to remove the mis-framing border. This was due to a change in framing when I did a meridian flip half way through the capture. It does act as a reference for pure black though Ooops - forgot to flip it too - for some reason the FITS file causes a horizontal flip.

[nytecam]

Gina - facinating progress on your processing of this image - on the basis that the human eye, however close to M101, would never see this detail - the final result is stunning

[Gina]

Gina - facinating progress on your processing of this image - on the basis that the human eye, however close to M101, would never see this detail - the final result is stunning

Thank you

[RobH]

A great improvement in the image over the course of the thread Gina, but I reckon you could still improve on it

The stars still have sharpening halos, which detract from the overall image a bit, and it's a tad magenta overall.

Final colour balance can be done by going to IMAGE/ADJUSTMENTS/SELECTIVE COLOUR

This will give fine control over all areas of colour, and can also be used to stretch certain sections of the image.

Cheers

Rob

[Gina]

Thank you Rob And I agree that it could still be improved. Thanks for your advice

[badgerchap]

Really starting to look great there Gina. I have no technical advice to offer (as I far less experienced) so praise will have to do! A touch magenta-ey but the detail is fantastic, especially as you don't see many attempts at 101 that come out looking so fine.

Posted via Tapatalk on an ageing iPhone so please excuse any erroneous spellings or accidental profanities!